JP2000067785A - Glass bulb for cathode ray tube and manufacture of cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To be shared jointly by a bulb maker and a cathode ray tube maker, and write information capable of individually identifying a bulb by forming a two dimensional code comprising a plurality of dots printed by laser on the outer surface, and forming the dot with a recess having the specified depth and diameter. SOLUTION: A two dimensional code 3 printed on the outer surface of a glass bulb is constituted by arranging crosswise a plurality of dots. The dot is formed in glass plane so that plane contours becomes circular recess. In order to correctly read the two-dimensional code 3, the depth of the recess is made 5-100 μm and the diameter is made 50-400 μm. The ratio of the depth to the diameter is preferable to be 0.04-0.60. Regarding to the recess and projection of the printed surface of the glass bulb, surface roughness is specified so that when light is irradiated to the normal of the surface from an angle of 5-85 degrees, the S/N ratio of brightness by the dots and that by recess and projection is 1.5 or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass bulb for a cathode ray tube having a two-dimensional code composed of a plurality of dots on a predetermined portion of an outer surface, a method for manufacturing the glass tube for a cathode ray tube, and the use of the glass bulb for a cathode ray tube. The present invention relates to a method for manufacturing a cathode ray tube.

[0002]

2. Description of the Related Art Glass bulb information and work condition information (including work content information) are directly written as marking characters or codes on the outer surface of a glass bulb for a cathode ray tube (hereinafter referred to as a glass bulb), and are manufactured by reading these. A method for managing a process is conventionally known. Writing on the outer surface of the glass bulb is usually performed by direct printing or labeling with a heat-resistant material, or by sandblasting or laser printing.

For example, Japanese Patent Application Laid-Open No. 2-874 discloses a manufacturing control method for printing a bar code by using a CO ₂ gas laser masking method and reading the bar code to prevent a component combination error occurring at the time of manufacturing a cathode ray tube.
42. It is also possible to grasp the product content from the marking letters written with the laser,
-202051.

[0004] However, these conventional methods of writing marking characters and codes by printing or laser masking have the problem that all information must be rewritten one by one for each product. For example, in the laser masking method, writing is performed using laser light that has passed through a mask, so the contents of the written information cannot be changed without changing the mask. Can not respond. For this reason, the marking characters and barcode information up to now are restricted by the amount of writable information, and the type (size), the transmittance of the glass bulb, the presence or absence of surface reflection prevention processing, the specification of the production line, etc. Limited specific information on valves and information on working conditions etc. are managed for each group to support products that are mass-produced, and are not suitable for use as information means for individually identifying glass bulbs .

As a result, marking characters and bar codes printed on the outer surface of a conventional glass bulb with a laser are:
Including marking characters displayed by other methods,
Even if the information written by the glass bulb manufacturer is used by the cathode ray tube manufacturer, it is not enough for the information required by the cathode ray tube manufacturer. It writes in barcodes and manages the manufacturing process. Therefore, the conventional marking characters and barcodes are not shared by both glass bulb and cathode ray tube manufacturers.

[0006] A general method of printing marking characters and bar codes on glass with a laser is known. But,
On a glass surface that is transparent and not flat like a glass bulb and has a matte-like fine unevenness on the surface, marking characters etc. that can correspond to a large amount of information that can individually identify the glass bulb are printed and imaged No effective reading using an element has been proposed.

[0007] In the process of manufacturing panels and funnels of a conventional glass bulb manufacturer, the combination of working lines, dies, molding equipment, processing equipment, and the like is extremely wide in the steps of molding, processing, polishing, and the like. Therefore, when a trouble or defective product occurs, it takes a long time to track it, but no appropriate solution has been proposed yet.

Further, in the manufacturing process of such a glass bulb, for example, a product manufactured by the same mold and the same apparatus in the forming process is intentionally optimized for the next polishing process in which a large number of lines are present. There is also a problem that it is difficult to supply in a suitable combination. This may be the same for cathode ray tube manufacturers.

In other words, in the conventional marking characters and codes, due to the restriction due to the amount of information to be written, and the difficulty in writing the marking characters and the like to the glass bulb,
Glass bulb manufacturers and cathode ray tube manufacturers have limitations on how they can be used in their respective manufacturing processes. Glass that can be used at least by both manufacturers and eliminates the need for cathode ray tube manufacturers to print their own marking characters, etc. Methods for manufacturing bulbs and cathode ray tubes are not known.

On the other hand, in recent years, with the spread and spread of conventional barcodes, there has been a need for coding more information, printing in a smaller space, and the like, and two-dimensional codes are known as corresponding to these needs. I have. This two-dimensional code is a code display method in which information is written in both the horizontal and vertical directions, that is, two-dimensional directions, and various display forms are known. However, the application of a two-dimensional code to a glass bulb, particularly the application of a two-dimensional code formed from a plurality of dots, has not yet been studied. It is not known that the production process of the glass bulb and the cathode ray tube is appropriately controlled through the two-dimensional code printed on the glass bulb.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and a glass bulb maker and a cathode ray tube maker can share a predetermined portion on the outer surface of a glass bulb. Provided is a glass bulb on which a two-dimensional code composed of a plurality of dots can be printed, in which information for individually identifying the glass bulb can be written, and a manufacturing method for managing the manufacturing process of the glass bulb or the cathode ray tube through the two-dimensional code. The purpose is to do.

[0012]

The present invention has a two-dimensional code consisting of a plurality of laser-printed dots on the outer surface, the dots having a depth of 5 to 100 μm and a diameter of 5 to 100 μm.
Provided is a glass bulb for a cathode ray tube, comprising a concave portion of 0 to 400 μm.

Further, the present invention relates to a method for producing a molded article of 200-500
A step of printing a two-dimensional code consisting of a plurality of dots by a laser on the outer surface of the glass tube for a cathode ray tube in a state of ° C., a step of reading information written in the two-dimensional code, and forming a glass bulb for a cathode ray tube And a step of managing the subsequent processing operation based on the read information, wherein the two-dimensional code has at least serial information capable of individually identifying the glass bulb for a cathode ray tube. A manufacturing method is provided.

Further, the present invention provides a step of reading a two-dimensional code composed of a plurality of dots provided on the outer surface of a glass tube for a cathode ray tube and specifying the glass bulb for a cathode ray tube, Setting at least a preferable working condition of the cathode ray tube in the control device in accordance with the unique information; and sequentially reading the two-dimensional code in the manufacturing process and extracting a desired working condition set for the glass bulb for the cathode ray tube from the control device. Performing the operation specified by the control device, the two-dimensional code includes at least serial information that can individually specify the glass bulb for the cathode ray tube, and a part or all of the manufacturing process Provided is a method for manufacturing a cathode ray tube, which is managed based on information.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a two-dimensional code consisting of a plurality of dots is printed on a predetermined portion on the outer surface of a glass bulb for a cathode ray tube. Here, the glass bulb refers to any one of a panel for a color cathode ray tube (hereinafter, referred to as a panel), a funnel for a color cathode ray tube (hereinafter, referred to as a funnel), a glass bulb for black and white, and a glass bulb for a projection tube.
In the case of the panel and the funnel, the two-dimensional code is usually printed on both of them, but may be printed on only one of them.

The two-dimensional code according to the present invention is constituted by arranging a plurality of dots in a two-dimensional direction, that is, vertically and horizontally. Although the basics of the two-dimensional code are substantially the same as those known so far, they will not be described in detail, but the feature is that information is specified by the dot arrangement position. The information amount of the two-dimensional code can be appropriately adjusted by increasing or decreasing the number of dots and the arrangement of the dots.

The shape of the dots constituting the two-dimensional code is not conscious of the thickness of a line like a so-called bar code, but can be recognized as a point such as a circle or an ellipse. Are preferred. When a two-dimensional code is printed by arranging dots, the two-dimensional code is usually printed in a matrix format such as a data matrix (Data Matrix) or a vericode (Veri Code). May be used.

In the present invention, a laser is particularly preferable for actually printing a two-dimensional code as a concave portion using dots on the outer surface of the glass bulb. The main reason is that even if the laser has fine irregularities on the printing surface of the glass bulb, it is possible to accurately and quickly print dots that can be automatically read by the sensor if you properly select the shape of the concave part that forms the dot Because.

Furthermore, the two-dimensional code printed on the outer surface of the molded glass bulb must be chemically and physically durable in the subsequent glass bulb manufacturing process and cathode ray tube manufacturing process. Must. In particular, since the cathode ray tube is subjected to a heat treatment at a high temperature of about 440 ° C. in the manufacturing process, it is necessary to be able to withstand the heat, and the printing by the laser can satisfy almost all of them.

One example of a two-dimensional code dot printed on a glass bulb with a laser is shown in FIG. The dots are formed as concave portions 26 having a circular or substantially circular planar outline on the glass surface. In FIG. 3, L is the diameter of the concave portion 26, and d indicates its depth. A projection 25 is usually formed around the recess 26. The depth d of the concave portion 26 when the projection 25 is formed is based on the top of the projection 25 as illustrated. The shape of the inner surface of the concave portion 26 is not particularly limited, but is substantially as shown in FIG.

FIG. 4 shows another shape of the concave portion 26. When the depth d becomes too large with respect to the pitch, the concave portion 26
Adjacent recesses 26 may be connected as shown. In this case, the diameter L and the depth d of each recess 26 are measured as shown. The concave portion 26 is formed as a substantially circular dot, but if it is not circular, it has the maximum diameter.

In order to read a two-dimensional code accurately,
It is necessary to control the depth d and the diameter L of the recess 26 to be constant. The reading of the two-dimensional code is affected by the performance of the reading device, the size (diameter) of the dot, the surface properties of the printing surface, and the like. The depth d of 5 to 100 μm is appropriate for a normal glass bulb. Especially 10-5
0 μm is desirable. Further, the diameter L is suitably from 50 to 400 μm, particularly preferably from 90 to 250 μm. Generally, when the depth d decreases, the diameter L decreases.
If it is less than μm, L will also be less than 50 μm, making it difficult to read the two-dimensional code accurately.

On the other hand, if d exceeds 100 μm and L exceeds 400 μm, not only is it difficult to print with a laser, but also chatter is likely to occur around the concave portion 26,
Or because the strength is reduced due to the excessively large concave portion and breakage occurs when vacuum stress acts on the glass bulb,
Not preferred. In addition, since the projection 25 around the concave portion 26 raises the glass with respect to the glass surface, it has the effect of increasing d and enhancing the brightness of the reflected light from the dot to facilitate detection.

Further, it is preferable that the concave portion 26 of the dot forming the two-dimensional code has a depth d / diameter L of 0.04 to 0.60. It is particularly desirable that d / L is 0.09 to 0.35. The concave portion 26 where d / L is smaller than 0.04
The depression is small and optically inconspicuous. For this reason, when reading a two-dimensional code, it is not possible to sufficiently obtain the brightness of the dots, and it is difficult to accurately recognize the dots. In the case of a glass bulb, this tendency is remarkable because the surface 28 generally has not a mirror surface but fine irregularities.

Further, a concave portion having a d / L of greater than 0.60 has a sharp concave portion, which tends to cause chatter at the periphery of the concave portion, and a sharp and relatively deep concave portion. The strength of is weakened. As a result, when the cathode ray tube is used, the concave portion is likely to cause breakage, which is not preferable.

It is desirable that the printing surface of the glass bulb be as smooth as possible irrespective of the printing method. But,
In laser printing, fine irregularities on the printing surface are allowed in the following range. In other words, the printing surface of a glass bulb having fine irregularities is 5
When light is irradiated from a direction of up to 85 degrees, the S / N ratio of the intensity of light and dark due to the dots of the two-dimensional code formed on the printing surface and the intensity of light and dark due to the unevenness is 1.5 or more. Any surface roughness is acceptable. Here, the intensity of the light and dark due to the unevenness and the like means the intensity of the light and dark caused by the unevenness and other noises. If the S / N ratio is smaller than 1.5, it becomes difficult to decode the two-dimensional code.

In a preferred embodiment of the present invention, in order to eliminate or minimize the influence of the surface roughness of the printing surface, the printing surface of the glass bulb is partially made a mirror surface or a smooth surface close to the mirror surface. Is recommended. Such smoothing can be easily obtained by surface treatment of a molding die or polishing after molding.

The position of the printing surface when printing a two-dimensional code on a glass bulb is not specified. However, due to the ease of printing and reading, the flatness of the outer surface of the glass bulb, etc., the center of the long side of the glass bulb is usually used. Is selected as the optimal position. Further, in order to improve the flatness of the printing surface, a flat or almost flat pedestal or depression may be provided in the printing portion of the glass bulb.
These pedestals or depressions may be mirror-finished to smooth the surface.

Next, information to be written in the two-dimensional code will be described. The two-dimensional code according to the present invention includes a base composition, a product name, a part arrangement, a product dimension, a wall thickness, a manufacturing date, a molding die, presence or absence of surface treatment, and serial information capable of individually specifying a glass bulb or a cathode ray tube. The information includes one or two or more types of information that are appropriately selected from unique information and operation information such as a processing line, a processing operation, and processing conditions in a manufacturing process of a glass bulb and a cathode ray tube. The two-dimensional code of the most preferred embodiment has at least information that can individually specify the glass bulb, that is, serial information.

The serial information gives each glass bulb a number, for example, so that it can be clearly distinguished from others in the manufacturing process of the glass bulb or the cathode ray tube. As a result, if this uniform number is associated with a control device such as a computer, the specific information of the glass bulb such as the size, thickness, manufacturing date, base composition, molding die, presence or absence of surface treatment, etc. of each glass bulb is obtained. And / or work information such as a processing line, a processing operation, and processing conditions in the manufacturing process of the glass bulb and the cathode ray tube can be appropriately taken out from the control device, and the manufacturing process can be managed using the serial information.

For example, when a bulb manufacturer provides dimensional information on each glass bulb together with its serial information to a cathode ray tube maker, the cathode ray tube maker reads the information at the time of manufacturing the cathode ray tube, and utilizes this dimensional information. To assemble the cathode ray tube. As a result, the quality and yield of the cathode ray tube are improved.

In this case, part or all of the unique information and the work information of the glass bulb except for the serial information is input to another recording medium corresponding to the serial information, and the serial number printed on the glass bulb is input. The information may be appropriately taken out from the recording medium based on the information.

As another information writing example of the two-dimensional code, there is a method of writing at least a part of the unique information and the work information together with the serial information in one two-dimensional code. According to this method, information or data on the glass bulb can be retrieved and used at any time by reading the two-dimensional code. Further, the two-dimensional code and a character character or the like for displaying the two-dimensional code may be printed together so that the unique information written in the two-dimensional code can be visually confirmed. If this character character or the like is input in advance to a two-dimensional code, for example, a laser printing device, the character character or the like can be printed simultaneously with the printing of the two-dimensional code using dots without a special device.

Further, the present invention is not limited to a glass bulb,
The present invention can also be applied to glass products such as automotive glass, for example, display substrate glass such as TFT.

[0035]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a data matrix type two-dimensional code 3 and characters representing the unique information of the funnel written in the two-dimensional code at a position on the outer surface 20 mm higher than the sealing end surface 2 at the center of the long side of the funnel 1. No. 4 was printed by laser marking. The serial information for specifying the funnel is written in a two-dimensional code including a plurality of dots. 2D code 3
Has a size of 6 mm square, a dot depth of about 20 μm, and a diameter of about 150 μm.

FIG. 2 shows a data matrix type two-dimensional code 3 similar to the funnel 1 shown in FIG.
And character 4 are printed. Regarding the size of the two-dimensional code 3, the depth and diameter of the dot are the same as those of the funnel 1 described above. These funnel and panel dots had a depth / diameter of 0.15.

FIG. 5 is a schematic diagram when the two-dimensional code 3 is printed on the panel 5. The two-dimensional code 3 is printed by the laser printing device 8 on the conveyer 7 for transporting the panel 5 formed from the molten glass by the forming device (not shown) to the next step. In this example, printing was performed at the same position as in FIG. 2 with the surface temperature of the panel being about 380 ° C. When two-dimensional codes were continuously printed on 50 panels 5 using this apparatus, no cracks or chatters occurred in the dots of the two-dimensional codes.

These panels 5 on which two-dimensional codes are printed
To the reading device shown in FIG.
The two-dimensional code 3 was read on the conveyor 9 using the camera 11 and decoded by the image processing device 12. At this time, the angle of the diffusion light source 10 (the angle 13 with the normal 27 shown in FIG. 7) is set to 3
It was set to 0 degrees. As a result, it was possible to accurately read the two-dimensional codes of all the 50 panels, and to confirm that each panel was individually specified by the serial information written in the two-dimensional code 3.

Next, an example of use in a glass bulb manufacturer will be described. FIG. 8 shows an example of the case of a panel. A two-dimensional code is printed on the formed panel (not shown) using the laser printing device 8 at a surface temperature of about 380 ° C. A two-dimensional code reading device is installed in each process such as processing, polishing, inspection, and packaging of the panel. In FIG. 8, for example, a reading device 23 is provided in the processing step 21 and a reading device 24 is provided in the polishing step 22, respectively.
At this time, for example, the number of the used processing machine or polishing machine is associated with the individual number recorded in the read two-dimensional code by the host computer 16.

Therefore, by comparing the individual number of the two-dimensional code with the host computer 16 at the final packaging stage, the history of the panel can be fully grasped. When a trouble occurs, by examining the two-dimensional code of the product, the cause of the trouble can be grasped earlier than before. Thereby, the production yield can be improved.
The method of using such a two-dimensional code is the same for a funnel.

FIG. 9 shows another example of use in a panel at a glass bulb manufacturer. Similarly, a two-dimensional code is printed on the formed panel using the laser printing device 8 at a surface temperature of about 380 ° C. This panel is a processing step 21
Each time the process passes, the two-dimensional code is read by the reading device 23 installed in the process, and the machine in which this panel is processed, the pressed mold, and the like are associated and recorded in the host computer 16. I do. The panel which has completed the processing step is continuously fed to the next polishing step 22.

In FIG. 9, three processing steps 21 and four polishing steps 22 are provided. Each reference numeral is represented by one series. When the panel is sent to the polishing process 22, the two-dimensional code printed on the panel is read by the respective reading devices 24 installed in each polishing process 22. Then, a panel manufactured by a machine having an optimum type or an optimum mold and a processing process for the polishing process is collated and selected in the host computer 16 and selectively supplied to a polishing line that matches the panel.

As a result, processing and polishing can be performed with a more optimal combination, which leads to an improvement in manufacturing yield. In the past, a person had to visually confirm and change the polishing line to the optimal polishing line, but this work can be eliminated. Further, it is possible to reduce the number of transporting facilities connecting each processing step and each polishing step.

Although the examples of the processing step and the polishing step have been described above, the same applies to each of the steps of molding and processing, processing and polishing, polishing and inspection, inspection and packaging. Further, it can be similarly applied to a funnel.

FIG. 10 shows a two-dimensional code printed on a glass bulb (panel, funnel) according to the present invention shared by a glass bulb manufacturer 14 and a cathode ray tube manufacturer 19.
An example of the case of utilizing is shown. Glass bulb manufacturer 14
, A two-dimensional code 3 incorporating the unique information of the glass bulb indicating the production date, the base composition, the glass bulb characteristics and the like and the serial information for individually specifying the glass bulb using the laser printing device 8 and the character 4 representing the unique information. (See FIGS. 1 and 2).

When the panel 5 and the funnel 1 are delivered to the cathode ray tube maker 19, the individual number specified by the two-dimensional code 3 is read by the reading device 15. From the information stored in the host computer 16, specific information required by the cathode ray tube maker of each glass bulb corresponding to the individual number, for example, data such as a product type, a transmittance, a pin position, and a meat pressure is extracted. These data are input to the flexible disk 17 and supplied to the cathode ray tube maker 19 together with the glass bulb.

The cathode ray tube maker 19 combines the information required for the production management of the cathode ray tube maker based on the information of the flexible disk 17 with the individual numbers of the two-dimensional code in the host computer 18.
Thereafter, the panel 5 or the funnel 1 on which the two-dimensional code 3 is printed is read by the host computer 18 according to the two-dimensional code 3 read by the reading device 20 each time.
And exchange necessary information to manage the manufacturing process. Here, necessary information can be transmitted via, for example, a network without using the flexible disk 17, and there is no particular limitation as long as it is a means for transmitting information.

The cathode ray tube maker 19 can also propose another method. From the panel 5 or the funnel 1 on which the two-dimensional code 3 is printed,
Is read by the reading device 20. As a result, the information on the panel 5 or the funnel 1, which has been obtained visually, can be read mechanically. Next, the host computer 18 associates the information on the manufacturing process of the cathode ray tube maker stored in advance with the read information, and specifies information necessary for the production control of the cathode ray tube maker so as to be compatible with the panel or the funnel. I do.

In the cathode ray tube manufacturing process of the cathode ray tube manufacturer, when the panel 5 or the funnel 1 is supplied, the host computer 18 selects the specified information by the two-dimensional code 3 printed on the panel 5 or the funnel 1. To control the manufacturing process.

[0050]

According to the present invention, at least information or data relating to a glass bulb is printed by a two-dimensional code composed of dots, and when the dots are formed as recesses, the depth and diameter of the recesses are set to desired sizes. By doing so, the two-dimensional code can be accurately printed with a laser and read by an image sensor. As a result, both the glass bulb manufacturer and the cathode ray tube manufacturer can share the information specified by the two-dimensional code, which makes the management of the manufacturing process more efficient and expands the range of manufacturing management at each manufacturer, resulting in lower production costs. Can be reduced and the yield can be improved.

Since printing is performed by laser, glass bulb manufacturers can eliminate the expensive printing by sandblasting which has been conventionally used, and cathode ray tube manufacturers do not need to attach expensive heat-resistant labels and the like.

When serial information of a glass bulb is incorporated in the two-dimensional code, each manufacturer needs this serial information and each manufacturer in a computer when utilizing manufacturing management and product information. Information can be associated and shared. As a result, the data of the glass bulb specified by the two-dimensional code can be supplied from the glass bulb manufacturer to the cathode ray tube maker via a flexible disk or the like, and the work of the cathode ray tube maker conventionally performing printing preparation work and input work can be omitted. .

Further, since a glass bulb manufacturer or a cathode ray tube manufacturer can easily confirm what history the glass bulb has passed by comparing the serial information with the host computer, when a trouble occurs, the trouble occurs. The cause can be grasped more quickly than before, and thereby the production yield can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of printing a two-dimensional code on a funnel.

FIG. 2 is a front view showing an example of printing a two-dimensional code on a panel.

FIG. 3 is an enlarged sectional view of a dot printed by a laser.

FIG. 4 is an enlarged sectional view of another dot printed by a laser.

FIG. 5 is a perspective view of a two-dimensional code printing device using a laser.

FIG. 6 is a perspective view of a reading device of a two-dimensional code printed by a laser.

FIG. 7 is an explanatory diagram showing a relationship between incident light and reflected light in a two-dimensional code reading device printed by a laser.

FIG. 8 is a schematic diagram showing an example of using a two-dimensional code in a glass bulb manufacturer.

FIG. 9 is a schematic view showing another example of using a two-dimensional code in a glass bulb manufacturer.

FIG. 10 is a schematic diagram showing an example of using a two-dimensional code in a glass bulb manufacturer and a cathode ray tube manufacturer.

[Explanation of symbols]

 1: funnel 3: two-dimensional code 5: panel 8: laser printing device 11: CCD camera

Claims (10)

[Claims] 1. A cathode ray line having a two-dimensional code consisting of a plurality of dots printed by a laser on the outer surface, wherein said dots comprise concave portions having a depth of 5 to 100 μm and a diameter of 50 to 400 μm. Glass bulb for pipe. 2. The two-dimensional code includes a base composition, a variety name,
Claims that include at least serial information among specific information such as the arrangement of parts, product dimensions, and serial information that can individually specify a glass bulb or a cathode ray tube for a cathode ray tube, and operation information such as a processing line, a processing operation, and processing conditions. Item 7. A glass bulb for a cathode ray tube according to Item 1. 3. The glass bulb for a cathode ray tube according to claim 1, wherein the recesses of the dots forming the two-dimensional code have a depth / diameter in a range of 0.04 to 0.60. 4. The intensity of light and darkness due to dots of a two-dimensional code when the surface on which the two-dimensional code is printed has irregularities and light is irradiated from a direction of 5 to 85 degrees with respect to a normal to the surface. 4. The glass bulb for a cathode ray tube according to claim 1, wherein the S / N ratio of the intensity of light and darkness due to the unevenness is 1.5 times or more. 5. A glass bulb for a cathode ray tube according to claim 1, wherein a pedestal or a recess having a flat or nearly flat surface is provided on an outer surface on which the two-dimensional code is printed. 6. A surface where a two-dimensional code is printed is a mirror surface or a state close to a mirror surface.
The glass bulb for a cathode ray tube according to the above. 7. The glass bulb for a cathode ray tube according to claim 2, wherein a part or all of the information other than the serial information in the two-dimensional code is provided as a marking character. 8. A step of printing a two-dimensional code composed of a plurality of dots on the outer surface of a glass bulb for a cathode ray tube at a temperature of 200 to 500 ° C. after molding by a laser, and information written in the two-dimensional code. The step of reading the, and the processing work after molding of the glass tube for a cathode ray tube, including the step of managing with the read information, the two-dimensional code has at least serial information that can individually specify the glass bulb for the cathode ray tube A method of manufacturing a glass bulb for a cathode ray tube. 9. A step of reading a two-dimensional code composed of a plurality of dots provided on an outer surface of a glass tube for a cathode ray tube and specifying the glass bulb for a cathode ray tube, and corresponding to the specific information of the specified glass bulb for a cathode ray tube. Setting at least a preferable operating condition of the cathode ray tube in the control device, and a step of sequentially reading the two-dimensional code in a manufacturing process and extracting a desired operating condition set for the glass bulb for the cathode ray tube from the control device; Performing the work specified by the apparatus, wherein the two-dimensional code includes at least serial information that can individually specify the glass bulb for the cathode ray tube, and manages a part or all of the manufacturing process based on the serial information. A method for manufacturing a cathode ray tube. 10. The method for manufacturing a cathode ray tube according to claim 9, wherein said two-dimensional code comprises dots printed by a laser.