JPH11348060A - Manufacture of transparent resin plate for cathode-ray tube display and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove mixing of bubbles and internal strain in a transparent resin plate used for lightening the front panel part of a cathode-ray tube display. SOLUTION: In a first process, a flat transparent resin plate, in which little bubbles are included, is manufactured. The resultant plate is formed in the following process. In forming, the transparent resin plate 1 is placed on a lower mold 2 (or 2a-2c) so as to be carried, after being pre-heated up to a temperature necessary for forming, to a forming position and then fixed with positioning mechanisms 4. Then, an upper mold 3 is lowered to a predetermined position by means of a pressurizing device 5 so as to form a required shape. Thus, by reducing the flow of a resin due to the difference of thickness, which is peculiar to the shape of a cathode-ray tube display, a high quality transparent resin plate is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a transparent resin plate for a cathode ray tube display for realizing a flat projection surface in a cathode ray tube display (hereinafter sometimes referred to as a CRT display). is there.

[0002]

2. Description of the Related Art In a CRT display used in a television receiver or the like, the outer surface of a glass front panel 12 of a CRT display 11 is made flat as shown in FIG. When a flat projection surface 14 is formed and the inner tube surface 13 of the front panel 12 is curved, the CRT display 1
1 increase in weight. For this reason, there is a problem that the total weight of the television receiver increases.

As a solution to this problem, Japanese Patent Application Laid-Open No. 6-44
No. 926 discloses that, as shown in FIG. 4B, a general front panel 15 having a uniform thickness along a curved tube surface 13 has an inner surface in contact with an outer surface of the front panel 15 and an outer surface which is flat. There is disclosed a structure in which a molded transparent resin plate 10 constituting a suitable projection surface 14 is provided, and the projection surface 14 is protected by a safety panel 16 to reduce the weight.

[0004] In addition, the safety panel 16
It is conceivable that the weight of the molded transparent resin plate 10 is further reduced by applying a coating capable of preventing moisture absorption and reflection of the molded transparent resin plate 10.

[0005] However, no special manufacturing method is described for the method of manufacturing the molded transparent resin plate 10.

For molding the transparent resin plate 10, molding by general injection molding is considered, and FIG. 5 shows a specific example. Referring to FIG. 5, an upper mold 23 forming a curved surface in contact with the front panel 15 and a lower mold 22 forming the projection surface 14 are attached so as to secure a predetermined distance D, and are vertically moved by an injection force. The molded transparent resin plate 10 can be molded by applying pressure to the molds 22 and 23 so as not to open and injecting the transparent resin 21 heated to a temperature at which it easily flows into the gap.

[0007]

By the way, the molded transparent resin plate 10 can be obtained by the above-mentioned injection molding method, but it has the following problems. Recent large size and front panel 1
5 is made closer to a flat surface, the radius of curvature R of the tube surface 13 is increased, and accordingly, the molded transparent resin plate 1 is increased.
0 indicates that the thickness D is smaller than the length E of the projection surface 14. Specifically, in a 36-inch CRT display, if the radius of curvature R of the tube surface is 2000 mm, the difference in thickness between the center and the end is about 20 mm. As described above, as the thickness D of the molded transparent resin plate 10 decreases, the surface in contact with the front panel 15 and the projection surface 1 due to distortion in the resin.
4 has a problem that the shape quality is deteriorated. Further, there is a problem that air bubbles are mixed into the transparent resin 21 by flowing the long distance of the transparent resin 21 across the projection surface 14 during injection molding.

In view of the above-mentioned conventional problems, the present invention provides a method for manufacturing a transparent resin plate for a cathode ray tube display, which can appropriately form a large-sized transparent resin plate free of air bubbles and distortion in the resin in a short time. It is intended to provide a device.

[0009]

According to the present invention, there is provided a method of manufacturing a transparent resin plate for a cathode ray tube display, comprising the steps of: setting a previously manufactured transparent resin flat plate free of air bubbles into a molding die; A step of pressure-molding a transparent resin flat plate with a mold, which is divided into a process of manufacturing a transparent resin flat plate free of air bubbles and a process of forming the transparent resin flat plate for a display. Accordingly, it is possible to avoid mixing of bubbles and occurrence of internal distortion caused by the flow of the transparent resin over a long distance, and it is possible to improve both the product yield and the processing accuracy.

[0010] In addition, by providing a step of preheating the transparent resin flat plate to a temperature suitable for molding, molding is facilitated. In addition, by providing an annealing step of gradually cooling after molding to remove distortion, even in the case of a large size, The occurrence of internal distortion can be more completely eliminated.

The apparatus for manufacturing a transparent resin plate for a cathode ray tube display according to the present invention comprises a first mold for holding a transparent resin plate and forming a projection surface of an image, and a portion in contact with a tube surface of the cathode ray tube display. A second mold, a positioning mechanism for aligning the first and second molds, and a pressure mechanism for pressing the first and second molds to form a transparent resin flat plate into a predetermined shape. With the above-described manufacturing method, a large-sized transparent resin plate free of air bubbles can be formed properly in a short time.

Further, if a preheating furnace for preheating the transparent resin plate is provided in advance, molding becomes easy, and if an annealing furnace for gradually cooling and removing distortion after molding is provided, even in the case of a large size, internal distortion is reduced. Occurrence can be more completely eliminated, and providing them is advantageous for consistently forming a molded transparent flat plate from a transparent resin flat plate of a material.

A plurality of first dies for holding a transparent resin flat plate and forming a projection surface of an image, a plurality of second dies for forming a portion in contact with a front panel of a cathode ray tube display, and a plurality of dies. An indexing mechanism capable of mounting the first and second dies, respectively, and positioning the first and second dies at a predetermined molding position, and mounting and removing at least the first die with respect to the indexing mechanism. And a pressurizing mechanism for pressing the first and second molds at the molding position to mold the transparent resin flat plate into a predetermined shape, to stabilize the shape after molding. The molding can be performed continuously by mounting and removing another mold at the time required for the molding.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a first embodiment of an apparatus for producing a transparent resin plate for a cathode ray tube display according to the present invention will be described.
The embodiment will be described with reference to FIGS.

As shown in FIG. 1, the basic structure of this embodiment is to place a transparent resin flat plate 1 containing no air bubbles on a lower mold 2 in advance, and then form the lower mold 2 by a transport mechanism (not shown). The upper mold 3 is pressed down to a predetermined position by the pressurizing mechanism 5 and the transparent resin flat plate 1 is formed into a required shape, and the molded transparent resin plate 10 is moved. Is configured to obtain. Acrylic or polycarbonate is suitable as a material for the transparent resin flat plate 1.

A step (not shown) of manufacturing the transparent resin flat plate 1 in this manner, the transparent resin flat plate 1 is moved to the lower mold 2 and the upper mold 3
The transparent resin seen in conventional injection molding traverses the projection surface from the end of the molded transparent resin plate by dividing into two steps of molding into a molded transparent resin plate 10 suitable for a cathode ray tube display using Incorporation of bubbles and occurrence of internal distortion caused by flowing over a long distance can be avoided, and the amount of change in shape of the transparent resin in the molding process can be reduced.

As a result, a suitable transparent resin plate for a cathode ray tube display having a predetermined shape without bubbles and internal distortion can be easily obtained, and the processing accuracy in the molding step and the product yield can be improved.

Next, a specific configuration will be described with reference to FIG. In FIG. 2, a preheating furnace 6 is provided at a position before the molding position on the conveying path of the lower mold 2, and the transparent resin flat plate 1 is heated to a temperature at which it can be easily molded. The preheating temperature at which the transparent resin plate 10 is brought into a state in which it can be easily molded is preferably in the range of 150 to 300 ° C. After preheating the transparent resin flat plate 1 in this way, the lower die 2 is transported to the molding position, positioned by the positioning mechanism 4, and the upper die 3 is lowered by the pressing mechanism 5, so that the transparent resin flat plate 1 has a required shape. It is held at a predetermined position and is cooled by being sandwiched between the lower mold 2 and the upper mold 3 to form a molded transparent resin plate 10 for a cathode ray tube display. Next, the lower mold 2 is carried into the annealing furnace 7 disposed behind the molding position on the transport path, and is gradually cooled to remove distortion inside the resin after molding.

The transparent resin flat plate 1 can be preheated outside the molding apparatus. However, when the preheating furnace 6 is attached to the molding apparatus and the molding is performed immediately before molding as in the present embodiment, the heating can be performed based on the temperature condition and the cooling condition at the time of actual molding, and the transparency up to the position of the lower mold 2 can be achieved. This is preferable because the temperature of the resin plate 1 can be prevented from lowering, and the resin material does not deteriorate due to excessive heating.

Although the molded transparent resin plate 10 can be cooled in the atmosphere, the annealing furnace 7 can be cooled as in this embodiment due to the difference in the thickness of the resin layer characteristic of the transparent resin plate for a cathode ray tube display. It is preferable that the resin is attached to a molding device to prevent distortion inside the resin after molding. As for these furnaces, only one of the preheating furnace 6 and the annealing furnace 7 can be attached as necessary, or both can be attached.

In the present embodiment, a plurality of lower dies 2 are used for a single upper
It is preferable that the molded transparent resin plate 10 is manufactured by sequentially transporting 2b and 2c).

(Second Embodiment) Next, a second embodiment of the apparatus for manufacturing a transparent resin plate for a cathode ray tube display according to the present invention will be described with reference to FIG. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the manufacturing apparatus of this embodiment, the upper die rotary index 8 and the lower die rotary index 9 that can rotate and index are provided, and the upper die 3a to 3d are attached to the upper die rotary index 8. ,
A lower mold rotary index 9 is provided with lower molds 2a to 2e on which the transparent resin 1 is mounted, and is mounted and removed (not shown).
, And can be taken out at a predetermined take-out position. In the lower die rotary index 9, the lower dies 2 a to 2 e are positioned at predetermined positions by a positioning mechanism (not shown), and a plurality of cylinders disposed at the mounting positions of the lower dies 2 a to 2 e. The upper molds 3a to 3a are driven by the pressure mechanism 5 (only one is shown in FIG.
It is configured so that the transparent resin flat plate 1 can be formed into a predetermined shape by being pressed toward 3d.

In the above configuration, each lower mold 2 (2
a-2e), the lower mold 2 on which the transparent resin plate 1 is placed is sequentially mounted on the lower mold rotary index 9, and the lower mechanism 2 is pressed by the pressing mechanism 5 at a predetermined molding position. The transparent resin flat plate 1 is formed by sequentially pushing up the mold 2 toward the corresponding upper mold 3 to a predetermined position to form the transparent resin flat plate 1 and holding the same until a predetermined shape is obtained, thereby forming a molded transparent resin plate 10. The lower mold 2 is released from the upper mold 3 before the removal position, and is removed from the lower mold rotary index 9 at the removal position.

According to the present embodiment, during the molding time until the upper and lower molds are separated after pressing, the other lower mold 2b is attached, the other lower mold 2d is taken out, and the upper mold rotary is removed. Indexing of the index 8 and the rotary index 9 for the lower mold can be performed. In this way, by using a plurality of pressing mechanisms 5 for a plurality of molds as a molding means, even when an approach time until pressurization or a slow cooling time after pressurization is required, a pair of molds can be used. The manufacturing time of the entire manufacturing apparatus can be shortened while securing the required optimum molding time.

In this embodiment, the upper and lower dies are arranged on the same rotating surface. However, a rotary index made up of two parallel disks is provided, and the upper and lower dies are mounted opposite to both disks and positioned. A structure provided with a mechanism or a pressurizing mechanism can be similarly realized. In addition, although an example in which molding is performed using an indexing mechanism and a pressing mechanism has been described, the same applies to a case in which, in addition to the indexing and pressing mechanism, a cam or the like that follows the pressing operation of the upper and lower molds is continuously moved. The effect of is obtained.

[0027]

According to the method for producing a transparent resin plate for a cathode ray tube display of the present invention, the process is divided into a process for producing a transparent resin plate free of air bubbles and a process for forming a transparent resin plate for a display. By doing so, it is possible to avoid the mixing of bubbles and the occurrence of internal distortion caused by the flow of the transparent resin over a long distance, and it is possible to improve both the product yield and the processing accuracy.

In addition, if a step of preheating the transparent resin flat plate to a temperature suitable for molding is provided, molding is facilitated, and if an annealing step of gradually cooling after molding to remove the distortion is provided, even in the case of a large size, the internal distortion is reduced. Can be completely eliminated.

Further, according to the apparatus for manufacturing a transparent resin plate for a cathode ray tube display of the present invention, the first mold for holding the transparent resin plate and forming a projection surface of an image, and the portion in contact with the tube surface of the cathode ray tube display And a positioning mechanism for aligning the positions of the first and second dies, and a pressure for pressing the first and second dies to form a transparent resin flat plate into a predetermined shape. Since a mechanism is provided, a large-sized transparent resin plate free from air bubbles can be formed in a short time by performing the above-described manufacturing method.

Further, if a preheating furnace is provided, molding is facilitated, and if an annealing furnace for slow cooling is provided, even when the apparatus is large, the generation of internal distortion can be completely eliminated. This is advantageous in that it is advantageous to consistently form a molded transparent flat plate from a resin flat plate.

Also, a plurality of first dies for holding a transparent resin flat plate and forming a projection surface of an image, a plurality of second dies for forming a portion in contact with a front panel of a cathode ray tube display, and a plurality of dies. An indexing mechanism capable of mounting the first and second dies, respectively, and positioning the first and second dies at a predetermined molding position, and mounting and removing at least the first die with respect to the indexing mechanism. And a pressurizing mechanism for pressing the first and second molds at the molding position to mold the transparent resin flat plate into a predetermined shape, to stabilize the shape after molding. It is possible to perform molding continuously by mounting and removing another mold at the time required for, and shorten the production time of the entire production equipment even if the molding time from pressurization to slow cooling is long. Can be.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram of a first embodiment of an apparatus for manufacturing a transparent resin plate for a cathode ray tube display according to the present invention.

FIG. 2 is a schematic configuration diagram of a specific configuration example of the embodiment.

FIG. 3 is a schematic configuration diagram of a main part of a second embodiment of the apparatus for manufacturing a transparent resin plate for a cathode ray tube display according to the present invention.

FIG. 4 shows a conventional cathode ray tube display, in which (a)
FIG. 2 is a configuration diagram of an example in which the projection surface is glass, and FIG. 2B is a configuration diagram of a main part of the configuration example in which the weight is reduced.

FIG. 5 is a schematic configuration diagram of a conventional transparent resin plate manufacturing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent resin plate 2 (2a-2e) Upper die 3 (3a-3d) Lower die 4 Positioning mechanism 5 Pressing mechanism 6 Preheating furnace 7 Annealing furnace 8 Rotary index for upper die 9 Rotary index for lower die 10 Molded transparent resin plate 11 CRT display 14 Projection surface 15 Front panel

Claims (7)

[Claims] 1. A method comprising: setting a transparent resin flat plate, which has been manufactured beforehand without any air bubbles, in a molding die; and pressure-forming the transparent resin flat plate with the molding die. A method for producing a transparent resin plate for a cathode ray tube display. 2. The method according to claim 1, further comprising the step of preheating the transparent resin plate to a temperature suitable for molding before molding.
The method for producing a transparent resin plate for a cathode ray tube display according to the above. 3. The method for producing a transparent resin plate for a cathode ray tube display according to claim 1, further comprising an annealing step of gradually cooling to remove distortion after molding. 4. A first mold for holding a transparent resin flat plate and forming a projection surface of an image, a second mold for forming a portion in contact with a tube surface of a cathode ray tube display, and first and second molds. And a pressing mechanism for pressing the first and second molds to form the transparent resin flat plate into a predetermined shape. Manufacturing equipment. 5. The apparatus for producing a transparent resin plate for a cathode ray tube display according to claim 4, further comprising a preheating furnace for preheating the transparent resin plate in advance. 6. The apparatus for manufacturing a transparent resin plate for a cathode ray tube display according to claim 4, further comprising an annealing furnace for gradually cooling to remove distortion after molding. 7. A plurality of first dies for holding a transparent resin flat plate and forming a projection surface of an image, a plurality of second dies for forming a portion in contact with a front panel of a cathode ray tube display, and a plurality of dies. An indexing mechanism capable of mounting the first and second dies, respectively, and positioning the corresponding first and second dies at a predetermined molding position, and mounting at least the first die to the indexing mechanism A cathode-ray tube display, comprising: a mounting / removing mechanism for performing removal, and a pressing mechanism for pressing the first and second molds at a molding position to form a transparent resin flat plate into a predetermined shape. Equipment for manufacturing transparent resin plates.