JP3061949B2 - Fluorescent display tube with built-in driving IC - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent display tube incorporating a driving IC.

[0002]

2. Description of the Related Art As shown in FIGS. 4A and 4B, a conventional fluorescent display tube without a built-in driver IC chip has a wiring formed by an Al sputtering method and an insulating layer covering the wiring. A segment layer 2 and a phosphor layer 3 are printed on the glass substrate 1 to form an anode substrate, and a filament 4 for obtaining electron emission and a support for holding the filament 4 on the anode substrate 5, and a grid 6 for controlling the movement of electrons.

In general, a fluorescent display tube is one in which electrons emitted from a filament 4 are accelerated by a grid 6 and incident on the phosphor layer 3 to cause the phosphor layer 3 to emit light.
Since both ends of the filament 4 are fixed to the metal support 5, the temperature at both ends does not rise to a predetermined temperature as compared with the vicinity of the center due to heat conduction, so that it is an area where sufficient electron emission cannot be obtained. I have.

As shown in FIGS. 4B and 4C, this area A is called an end cooling area, and is an area where a display segment cannot be provided.

[0005] Conventional drive IC built-in type (Chip In
Glass (hereinafter referred to as CIG) fluorescent display tube
The above-described end cooling using the driver IC chip 7 having the bonding pads 12 for input and output arranged on the four sides shown in FIG. 6 which has been used as a mold package IC in the drive circuit outside the fluorescent display tube until then is used as it is. Mounted on the area.

Further, as shown in FIGS. 5 (a) and 5 (b),
The die bonding process of mounting the IC chip 7 on the anode substrate in the conventional manufacturing process of the CIG fluorescent display tube includes the recognition of the anode substrate, the application of the IC chip fixing material, the recognition of the IC chip 7,
In the procedure of transferring the IC chip 7, the IC chip 7
In the wire bonding step of connecting the semiconductor chip and the substrate wiring with bonding wires, the steps of recognition of the IC chip 7, recognition of the anode substrate, and connection of the bonding pad on the IC chip 7 to the anode substrate wiring are performed as shown in FIG. The IC chip 7 mounted on the anode substrate is an IC chip 1-7a,
When the number of IC chips becomes two or more as in the case of the IC chip 2-7b, the procedure of the above-described die bonding step and wipe bonding step is repeated by that number.

[0007]

In this conventional CIG fluorescent display tube, as shown in FIG. 5B, a dimension C of an IC shield 9 for covering and shielding and protecting a driver IC chip 7 is shown.
Is larger than the end cooling area length A shown in FIGS. 4 (b) and 4 (c), so that the outer dimensions are larger than those of the fluorescent display tubes of FIGS. 4 (a) and 4 (b) which do not incorporate the IC chip having the same display contents. Become. This has the disadvantage that the material cost of the substrate is increased for the same display function, and the space factor of the set using the fluorescent display tube of the customer is reduced.

In the conventional CIG fluorescent display tube, when the number of outputs of one driver IC chip is insufficient for the number of display segments, as shown in FIG. 7, individually pelletized IC chips are used. Die bond,
Since the operation procedure of wire bonding is repeated by the number of IC chips, there is a problem that the operation cost increases.

An object of the present invention is to provide an inexpensive CIG fluorescent display tube without lowering the space factor.

[0010]

SUMMARY OF THE INVENTION The present invention provides an anode substrate,
A segment layer provided on the anode substrate, a phosphor layer formed on the segment layer, a filament stretched at a distance from the phosphor layer, and a support for supporting the filament, A driving IC built-in type fluorescent display tube comprising: a grid disposed between the phosphor layer and the filament; an IC chip mounted on the anode substrate for driving the segment layer; and an IC shield for shielding the IC chip. In the above, the IC chip is bonded only to the long side.
Formed in a rectangular shape with the
On the anode substrate in the end cooling area of the
The long side of the IC chip is perpendicular to the filament
To be mounted on.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 (a) and 1 (b) are a partially cutaway perspective view and a sectional view of an anode substrate according to a first embodiment of the present invention.
FIG. 2 is an enlarged plan view of the IC chip of FIG.

First, the length A of the end cooling area shown in FIGS. 4B and 4C is determined by the diameter of the filament core wire used. As shown in FIGS. 1 (a) and 1 (b), the length of the end cooling area of the filament 4 generally used in the CIG fluorescent display tube is 8.5 mm, and the metal support 5 which is more indispensable than this is used. , Grid 6, IC chip 7 by subtracting the size occupied by segment layer 2
The dimension usable for mounting is about 5.0 mm. In order to perform die bonding and wire bonding on the IC chip 7 within this dimension and cover the IC chip 9 with the IC shield 9, the short side length shown in FIG. 2 is 2.3 mm, the long side length is 6.1 mm and the long side shown in FIG. Driver I in which bonding pads 12 are arranged only on the side
C chip 7 was newly developed.

Thus, the driver IC chip 7 unique to the CIG fluorescent display tube and the IC shield 9 containing the same can be completely accommodated in the dead space in the end cooling region which always exists in the fluorescent display tube. It became.

FIG. 3 is an enlarged plan view of a peripheral portion of an IC chip according to a second embodiment of the present invention.

In the second embodiment, as shown in FIG.
By arranging the bonding pads 12 only on the two long sides of the chip 1-7a and the IC chip 2-7b, dicing is performed so that the plurality of IC chips 1-7a and 2-7b are not separated. The die bonding and the wire bonding can be performed in the state of being connected in the direction, and the chip is mounted on the anode substrate and connected to the substrate wiring 11 by one procedure like one chip.

[0017]

As described above, according to the present invention, the driver IC chip and the IC shield necessary for the CIG fluorescent display tube are completely housed in the dead space, which is the end cooling region of the filament which always exists in the fluorescent display tube. As a result, it has become possible to manufacture a high value-added CIG fluorescent display tube having the same external dimensions as a fluorescent display tube without a driver IC having the same display. This has the effect of reducing material costs related to external dimensions and improving the space factor for customer sets.

In addition, by performing die bonding and wire bonding without separating a plurality of identical IC chips, the procedure of the die bonding and wire bonding process can be completed in the same one time as one chip. This has the effect of reducing the manufacturing cost of the built-in CIG fluorescent display tube.

Furthermore, by mounting a plurality of IC chips without separating them in the long side direction, the space required in the long side direction of the IC chips is reduced, and the degree of freedom in designing the outer shape of the CIG fluorescent display tube is increased. This has the effect of causing

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view and a sectional view of an anode substrate according to a first embodiment of the present invention.

FIG. 2 is an enlarged plan view of the IC chip of FIG.

FIG. 3 is an enlarged plan view of a peripheral portion of an IC chip according to a second embodiment of the present invention.

FIG. 4 is a partially cutaway perspective view of an example of a conventional anode substrate of a fluorescent display tube without a built-in IC chip, a sectional view thereof, and a characteristic diagram showing a temperature distribution of a filament.

FIG. 5 is a partially cutaway perspective view and a sectional view of an example of an anode substrate of a conventional CIG fluorescent display tube.

FIG. 6 is a plan view of an example of a conventional IC chip of a CIG fluorescent display tube.

FIG. 7 shows an IC mounted with a plurality of conventional CIG fluorescent display tubes.
It is a top view of an example of a chip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Segment layer 3 Phosphor layer 4 Filament 5 Support 6 Grid 7, 7a, 7b IC chip 8 Bonding wire 9 IC shield 10 Insulating layer 11 Substrate wiring 12 Bonding pad

Claims (2)

(57) [Claims] To 1. A insulating substrate, segmented layer, phosphor layer, filament, support for supporting the filaments, and the fluorescent display tube having a grid, the
The shape between the support and the adjacent segment layer
A driving IC chip in an end cooling area to be formed;
An IC shield for shielding the IC chip is further provided.
The side of the IC chip along the support is a long side.
Which encloses the IC chip.
The IC shield is housed in the end cooling area
And the bonding chip of the IC chip.
A driving IC built-in type fluorescent display tube, wherein the head is provided only along the long side . 2. The IC chip according to claim 1, wherein said IC chip comprises a plurality of chips which are not separated.
The fluorescent display tube with a built-in driving IC according to the above.