KR20050009054A - Dual layer vacuum fluorescent display - Google Patents

Abstract

PURPOSE: A dual side vacuum fluorescent display is provided to form brand name or logos on a rear substrate, and display the brand name or logos by emitting light from phosphor layers. CONSTITUTION: A dual side vacuum fluorescent display comprises a front display unit, a rear display unit, a plurality of line cathodes, a first lead unit(606), and a second lead unit. The front display unit includes a first conductive layer formed into a predetermined information pattern on a front substrate(600), a first phosphor layer deposited on the first conductive layer, and a first grid electrode(608) formed into a predetermined pattern on the first conductive layer. The rear display unit includes a second conductive layer formed into a predetermined log pattern all over a rear substrate(620), and a second phosphor layer deposited on the second conductive layer. The line cathodes are arranged between the front display unit and the rear display unit. The first lead unit drives the front display unit, and the second lead unit drives the rear display unit.

Description

Dual layer vacuum fluorescent display

The present invention relates to a vacuum VFD, and more particularly to a double-sided light emitting type VFD.

Vacuum VFD (Vacuum Fluorescent Display, VFD) is a self-luminous element compared to other display devices, it has excellent brightness and display quality, so it can be clearly recognized, low voltage during operation, low power consumption, high reliability and long life. It is a display device with advantages such as guarantees and various colors. These VFDs are mainly used for parts with relatively simple display and high brightness, such as gas station and taxi fare calculators.

1A and 1B are diagrams for explaining the structure of a conventional cross-sectional light emitting type VFD, the front substrate 100, the side plate 102, the back substrate 104, the tandem cathode 106, the grid 108, An anode comprising a cathode fixing member 110, a lead portion 112, an anode conductive layer 118, and a fluorescent layer 120 is provided.

The VFD has a triode structure with an in-line cathode 106, a grid 108, and an anode 118 to display the desired pattern. The VFD accelerates collision of hot electrons emitted from the series cathode 106, which is provided as a filament, to the phosphor 120 with an electric field between the grid 108 and the anode 118, whereby in the excited phosphor 120 Display the information using the light coming out.

The tandem cathode 106 is formed with an oxide film of BaO, SrO, CaO, or the like on a tungsten core wire having a diameter of about 20 µm, and is supported at both ends by a cathode fixing portion 110 including a support and an anchor. The cathode 106 is heated by applying a constant voltage at both ends thereof, and emits hot electrons while maintaining a temperature of about 600 to 650 ° C.

The grid 108 is a metal mesh obtained by photoetching a thin film of stainless plate into a hexagonal shape. The grid 108 blocks or accelerates the electrons emitted from the cathode 106 and also moderates the change in the electric field distribution so that the electrons hit the phosphor of one pixel evenly.

The anode 118 is a conductive layer formed in the shape of a pattern to be displayed, and is formed of a thick film such as graphite or a thin film conductor such as aluminum, and the phosphor 120 is coated on the anode 118. When a constant voltage is applied to the anode 118, the electrons accelerated and diffused in the grid 108 collide to excite the phosphor 120 and emit light.

Compared with the above-mentioned top emission type VFD, the double-side emission type VFD has a structure in which a triode structure is provided on both the front substrate side and the rear substrate side. Such a double-sided light emitting type VFD is disclosed in detail in Korean Patent Laid-Open Publication No. 1994-12478. 2 is a view showing an example of a conventional double-sided light emission type VFD disclosed in the above publication. 3 is a view showing another example of the conventional double-sided light emission type VFD disclosed in the above-mentioned patent publication. 4 is a view for explaining the getter structure of the conventional double-sided light emission type VFD disclosed in the above-mentioned patent publication.

Referring to FIG. 2, the conventional double-sided light emission type VFD has a triode structure of a cathode 201, a grid 202, 203, and an anode 204, 206 on both sides of a front substrate 208 and a rear substrate 209. Is provided. Phosphors 205 and 207 are coated on the anodes 204 and 206 on both sides of the substrate. In addition, the front substrate lead portion 210 and the rear substrate lead portion 211 is provided to drive the front substrate 208 and the back substrate 209, respectively.

Referring to FIG. 3A, a conventional double-sided light emission type VFD includes a front substrate 303, a back substrate 304, and a side plate 305, and cathodes on both sides of the front substrate 303 and the rear substrate 304. 301, grids 335 and 325 and anodes 334 and 324 are provided with a front substrate display portion 306 and a rear substrate display portion 307. The front substrate display unit 306 includes an anode 334 having a phosphor layer 333 disposed on the anode conductor 330, a grid 335, and a wiring conductor 331. The back substrate display unit 307 includes an anode 324, a grid 325, and a wiring conductor 320 provided with a phosphor layer 323 on the anode conductor 322. The wiring conductor 320 and the anode are provided. The conductor 322 is electrically connected through the through hole 321 formed in the insulating shielding film 313. In addition, the back substrate display unit 307 is driven by an external lead 309 connected to the wiring conductor 320.

3B illustrates the structure of the external lead 308 driving the front substrate display unit 30. Referring to FIG. 3B, the rear substrate 304 is exposed to the outside and is bent toward the front substrate 303 to be connected to the front substrate wiring conductor 331.

Referring to FIG. 4, in the getter structure of the conventional double-sided light emitting type VFD, the getter 407 is provided to face the front substrate 403 by the support member 508. Getter flashing occurs toward the front substrate 403 by high frequency induction or direct energization, so that the getter film 409 is formed inside the front substrate 403. Therefore, the getter film is observed on the front substrate 403.

Accordingly, a technical problem to be achieved by the present invention is to provide a VFD capable of emitting a product brand or a manufacturer's logo, etc. from the rear substrate side with a self-luminous phosphor, apart from the information display on the front substrate side.

Another object of the present invention is to provide various display methods using the double-sided light emitting type VFD.

1A and 1B are diagrams for explaining the structure of a conventional cross-sectional light emitting type VFD.

2 is a view showing an example of a conventional double-sided emission type VFD.

3 is a view showing another example of a conventional double-sided light emission type VFD.

4 is a view for explaining the getter structure of the conventional double-sided light emission type VFD.

5 is an exploded perspective view for explaining the structure of the double-sided light emitting type VFD according to an embodiment of the present invention.

FIG. 6 is a plan view of the double-sided light emitting type VFD of FIG. 5 viewed from the A side of the front substrate.

FIG. 7 is a cross-sectional view B-B of the double-sided light emitting type VFD shown in FIG. 6.

FIG. 8 is a cross-sectional view taken along line C-C of the double-sided light emitting type VFD shown in FIG. 6.

FIG. 9 is a sectional view taken along line D-D of the double-sided light emitting type VFD shown in FIG. 6.

10 is a view for explaining the getter portion structure of the double-sided light emitting type VFD according to the present invention.

11 is a view for explaining an embodiment of the double-sided light emitting type VFD according to the present invention further provided with a second grid.

12 is a diagram illustrating an example of a logo pattern formed on the rear substrate and an information pattern formed on the front substrate.

13 is a view showing a light emission sequence of a substrate for explaining a preferred embodiment of a display method using a double-side light emission type VFD according to the present invention.

<Explanation of symbols for the main parts of the drawings>

600 ...... Front board 602 ...... Front board display

604a ... first conductive layer 604b ... first phosphor layer

606 ... first lead part 608 ... first grid

610 ...... cathode 612 ...... cathode support

614 ... cathode anchor 616 ... getter part

618 ...... Front board terminal 620 ...... Rear board

622 ... back panel display 624 ... logo engraved pattern

Logo embossed pattern 626 ...... Second lead

628 ...... Rear board terminal 630 ...... Side plate

640 ...... Second Grid

In order to achieve the above technical problem, a double-sided light emitting type VFD having a front substrate and a back substrate according to the present invention includes a first conductive layer formed on a top surface of the front substrate in a predetermined information pattern and a first coating layer formed on the first conductive layer. A front substrate display having a first phosphor layer and a first grid electrode formed in a predetermined pattern on the first conductive layer; A rear substrate display having a second conductive layer having a predetermined logo pattern formed on the entire upper surface of the rear substrate, and a second phosphor layer coated on the second conductive layer; A plurality of line cathodes disposed between the front substrate display portion and the rear substrate display portion; A first lead part driving the front substrate display part; And a second lead part for driving the back substrate display part.

The second conductive layer of the rear substrate display unit may have a pattern embossed based on the outline of the logo. In addition, the second conductive layer of the rear substrate display unit may have a pattern formed in an intaglio based on the outline of the logo. In addition, the second conductive layer of the rear substrate display unit may be formed by being separated into an embossed conductive layer and an intaglio conductive layer based on the contour of the logo.

In the second phosphor layer of the back substrate display unit, phosphor layers having different colors may be applied to the embossed conductive layer and the engraved conductive layer.

Each electrode of the second lead portion may include: a first portion directly connected to an external power source through the rear substrate display portion; And a second portion having one end connected to the first portion and the other end connected to the second conductive layer. Here, the first portion and the second portion may be connected by welding. In addition, the second part is provided with a leaf spring, one end of the second part is connected to the first part by welding, and the other end of the second part is a free end, which is pressed against the conductive layer by a spring force. Can be.

The rear substrate display unit may further include a second grid electrode formed in a predetermined pattern on a substrate around the second conductive layer.

The double-sided light emitting type VFD according to the present invention may be provided with a getter part which is fixed to the inside of the front substrate and is formed to form a getter film inside the back substrate.

In order to achieve the above another technical problem, a display according to the present invention of the double-sided light-emitting type VFD having a front substrate having an information pattern and a back substrate having a predetermined logo pattern embossed and engraved is (a) the logo pattern Displaying an embossed logo pattern and / or an embossed logo pattern of the; And (b) displaying the information pattern. In step (a), the embossed logo pattern or the intaglio logo pattern may be selectively displayed. In the step (a), the embossed logo pattern or the intaglio logo pattern may be sequentially displayed. In the step (a), the embossed logo pattern and the intaglio logo pattern may be simultaneously displayed.

Hereinafter, the configuration and operation of the double-sided light emitting type VFD and its display method according to the present invention will be described in detail with reference to the accompanying drawings.

5 is an exploded perspective view for explaining the structure of the double-sided light emitting type VFD according to an embodiment of the present invention.

FIG. 6 is a plan view of the double-sided light emitting type VFD of FIG. 5 viewed from the A side of the front substrate.

In the present invention, the front substrate display unit 602 displays information to be displayed, and the rear substrate display unit 622 displays a simple pattern desired by the manufacturer, such as a logo or brand name of the manufacturer. Is provided for display.

5 and 6, the double-sided light emitting type VFD according to the present invention includes a front substrate 600 on which information is displayed, a back substrate 620 on which a predetermined logo is displayed, a side plate 630, Supports the first lead portion 606 for driving the front substrate, the second lead portions 626a, 626b, and 626c for driving the rear substrate, the first grid 608, the series cathode 610, and the cathode 610. The support 612, the anchor 614, the getter portion 616 is provided.

FIG. 7 is a cross-sectional view B-B of the double-sided light emitting type VFD shown in FIG. 6. FIG. 8 is a cross-sectional view taken along line C-C of the double-sided light emitting type VFD shown in FIG. 6.

Referring to FIGS. 7 and 8, the front substrate display unit 602, the rear substrate display unit 622, the line cathode 610, and the front substrate display unit 602 provided in the double-sided light emitting type VFD according to the present invention are driven. The structure of the second lead part 626 driving the first lead part 606 and the back substrate display part 622 will be understood.

A plurality of line cathodes 608 are provided between the front substrate display unit 600 and the rear substrate display unit 620. The line cathode 608 provided as a filament is formed of an oxide film such as BaO, SrO, or CaO on a tungsten core wire having a diameter of about 20 μm. It is installed to have a moderate tension between the) and is heated by applying a constant filament voltage at both ends to emit hot electrons.

The first grid 608 is a metal mesh formed by photo etching a thin film of a stainless plate into a predetermined shape, such as a hexagonal shape. The first grid 608 blocks or accelerates the electrons emitted from the cathode 610 and also moderates the change in the electric field distribution so that the electrons hit the phosphor 604b of one pixel evenly.

The front substrate display unit 602 includes a first conductive layer 604a formed on a top surface of the front substrate 600 in a predetermined information pattern, a first phosphor layer 604b coated on the first conductive layer 604a, and a first conductive layer 604b. The first grid 608 is formed on the first conductive layer 604a in a predetermined pattern. The first anode 604 is formed by the first conductive layer 604a and the first phosphor layer 604b. The first conductive layer 604a is formed on the front substrate display unit 602 according to the information to be displayed. An appropriate number of wires are connected to the first conductive layer 604a according to a driving method according to a design specification, for example, a dynamic driving method, a static driving method, or a dot matrix driving method. do.

The back substrate display unit 622 may be provided to selectively display a predetermined logo in an embossed or engraved manner. In order to selectively display the logo as embossed or engraved, only the logo engraved pattern may be provided on the back substrate display unit 622, or only the logo embossed pattern may be provided. In addition, both the logo embossed pattern 625 and the logo engraved pattern 624 are provided on the back substrate display unit 622, and only the logo embossed pattern 625 or the intaglio pattern 624 may be driven to be selectively displayed. Can be. To this end, the second conductive layers 624a and 625a of the back substrate display unit 622 may be formed by being separated into the logo embossed pattern 625 and the logo engraved pattern 624 based on the outline of the logo. 12 illustrates an example in which a logo of "SAMSUNG" is formed on the rear substrate 620 and an example in which an information pattern is formed on the front substrate 600. 12 and 7, when only the letter “S” is placed among the logos formed on the back substrate 620, the inner side corresponds to the logo embossed pattern 625 on the basis of the “S” contour, and the outer side is the outer side. Corresponds to the logo engraved pattern 624.

In addition, the back substrate display unit 622 may be driven such that only one of the logo embossed pattern 625 and the logo engraved pattern 624 is selectively emitted. The embossed pattern 625 and the logo engraved pattern 624 of the logo may be driven. May be driven to emit light at the same time, or the logo embossed pattern 625 and the logo engraved pattern 624 may be driven to sequentially emit light.

Here, phosphors of the same color may be coated on the embossed logo pattern 625 and the engraved logo pattern 624. When the phosphor having the same color is applied to the logo embossed pattern 625 and the logo engraved pattern 624, when the logo embossed pattern 625 and the logo engraved pattern 624 are driven to emit light simultaneously, the back substrate display unit 622 Will perform the same function as a backlight.

In addition, phosphors of different colors may be coated on the embossed logo pattern 625 and the engraved logo pattern 624.

Meanwhile, the lead portions 606 and 626 included in the double-sided light emitting type VFD according to the present invention will be described with reference to FIGS. 5 to 9 as follows.

5, 6, and 7, the first lead part 606 is provided to drive the first conductive layer 604a on the front substrate 600 on which the information display pattern is formed. Accordingly, the first lead portion 606 may include, for example, a dynamic driving method and a static (according to the number of information display patterns displayed on the front substrate display unit 600 and the method of driving the first conductive layer 604a). static) An appropriate number of lead pins may be provided according to a driving method or a dot matrix driving method. Referring to FIG. 8, the first lead part 606 is inserted into the front substrate 600 and is connected to the front substrate terminal portion 618 having an appropriate shape to drive the front substrate 600 on which an information pattern is formed.

5, 6, and 8, the second lead part 626 is provided to drive the back substrate 620. Here, the second lead part 626 is provided with a lead pin for driving one or more rear substrates 620. The number of lead pins of the second lead part 626 may be determined according to the number of divisions of the logo pattern provided on the back substrate 620.

Each of the lead pins constituting the second lead part 626 may be divided into a member of the first part 626a and a member of the second part 626b. The first part 626a is a part connected to the outside. The second portion 626b is interposed between the first portion 626a and the back substrate 620 to connect the first portion 626a and the back substrate 620. One end of the first portion 626a and the second portion 626b may be connected by welding. For this purpose, as shown in FIG. 6, the first portion 626a may be connected to a contact portion of the second portion 626b. Correspondingly shaped welds 626c may be provided.

As a result, both the first lead portion 606 and the second lead portion 626 are introduced into the frame between the front substrate 600 and the side plate 630, so that the first lead portion 606 is the front substrate 600. Directly connected to the second lead portion 626 is bent toward the rear substrate 620 as shown in Figure 8 is connected to the rear substrate 620.

Those skilled in the art, contrary to the structure shown in the drawing, both the first lead portion 606 and the second lead portion 626 are led to the back substrate 620, so that the first lead portion 606 and the second lead portion It will be appreciated that 626 may have an interchanged structure.

In the present invention, after the second portion 626b is processed as a separate component from the first portion 626a, the second portion 626b is combined with the first portion 626a to form one lead portion 626. In this configuration, the shape of the second lead portion 626 becomes very high in design freedom. In the embodiment shown in FIG. 6, the first portion 626a and the second portion 626b are welded at right angles to each other in the right direction, so that the shape of the second lead portion 626 is represented as a rectangular shape. However, according to the structure of the second lead portion 620 of the present invention, the first portion 626a and the second portion 626b may be welded at right angles to each other in the left direction, if necessary, and connected to the substrate even if they are not at right angles. It may be adjusted and welded at a suitable angle below.

Here, the second portion 626b may be provided as a leaf spring. FIG. 9 is a sectional view taken along line D-D of the double-sided light emitting type VFD shown in FIG. 6. One end of the second portion 626b provided as the leaf spring is connected to the welding portion 626c of the first portion 626a by welding, and the other end of the second portion 626b is a free end and is back by spring force. The substrate terminal 628 may be pressed against the substrate terminal portion 628. As described above, since the second lead portion 626 is pressed against the back substrate 620 by the leaf spring structure, sufficient contact stability can be ensured.

On the other hand, the structure of the getter portion 616 provided in the VFD according to the present invention will be described as follows. 10 is a view for explaining the structure of the getter unit 616 according to the present invention. The getter portion 616 is provided with a getter 816a and a getter support member 816b. The getter 816a is tightly fixed to the inner side of the front substrate 600 by the getter support member 816b to face the rear substrate 620. Under the getter part 616 structure, the getter film 818 is formed inside the back substrate 620. Therefore, the getter film 818 is not observed on the front substrate 600 side.

Meanwhile, as shown in FIG. 11, the back substrate display unit 622 may further include a second grid 620 formed in a predetermined pattern on a substrate around the second conductive layer. If the logo pattern formed on the back substrate 620 becomes complicated, the second grid 620 may be further selectively provided for good light emission.

Hereinafter, a preferred embodiment of the display method according to the double-sided light emission type VFD according to the present invention will be described as follows.

12 illustrates a logo pattern of the rear substrate 620 and an information display pattern of the front substrate 620. An embodiment to be described below is an embodiment using a VFD having both an embossed logo pattern and an intaglio logo pattern formed on the back substrate 620 based on the contour of the logo.

Fig. 13 shows a light emission sequence of a substrate for explaining a preferred embodiment of the display method using the double-sided light emission type VFD according to the present invention. First, the back substrate 620 is driven to turn on the embossed logo pattern and maintain it for a predetermined period of time (S100). After the step S100, the intaglio logo pattern is turned on and maintained for a predetermined period, and then turned off (step S102). After step S102, the embossed logo pattern and the intaglio logo pattern are simultaneously turned on and maintained for a predetermined period (step S104). After the step S104, the front substrate 600 is driven to display desired information (step S106). Here, steps S100 and S102 may be performed in a reversed order. In addition, the logo pattern of the back substrate 620 may be turned off after a predetermined period of time in step S104, or may be turned on while being turned on at the same time as the information pattern of the front substrate 600.

The display example shown in FIG. 13 may be extended to embodiments by various display steps as shown in Table 1 below.

Front panel information display (A) Back board logo display Embossed logo display (B) Negative logo display (C) Stage 1 ○ 2 steps ○ 3 steps ○ ○ 4 steps ○ 5 steps ○ ○ 6 steps ○ ○ 7 steps ○ ○ ○

As shown in Table 1, the turn on of the information display or the logo display may be performed sequentially or simultaneously. Wherein each step may be driven to turn on for a predetermined period, if necessary. In addition, various display methods may be derived by the combination of the respective steps.

For example, four steps may be performed after one step. That is, after the embossed logo display B is turned on and the predetermined period has elapsed (step 1), the embossed logo display B is turned off and the front substrate information display A can be turned on (step 4). Likewise, four steps may be performed after two steps.

In addition, five steps may be performed after one step. That is, the embossed logo display (B) is turned on and after a predetermined period of time (step 1), the embossed logo display (B) and the front substrate information display (A) can be kept on at the same time (step 5). Likewise, step 6 may be performed after step 2.

In addition, steps 1, 2 and 4 may be performed sequentially. That is, the embossed logo display (B) is turned on after a predetermined period (step 1), the negative logo display (C) is turned on and after a predetermined period (step 2), the front substrate information display (A) can be turned on ( Step 4). Likewise, steps 1, 2, 3 and 4 may be performed sequentially.

In addition, steps 1, 2 and 7 may be performed sequentially. That is, after turning on the embossed logo display (B) and after a predetermined period (step 1), turn on the embossed logo display (C) and after a predetermined period (step 2), embossed logo display (B), negative logo display (C) And the front substrate information display A can be kept turned on at the same time (step 7). Likewise, steps 1, 2, 3 and 7 may be performed sequentially.

Those skilled in the art will appreciate that some of the embodiments described above, using each step in Table 1, may be combined in a more wide variety of embodiments within the equivalent range.

As described above, according to the double-sided light emitting type VFD of the present invention, the following effects are obtained.

First, apart from the information display on the front substrate side, a product brand or a manufacturer's logo is formed on the rear substrate to emit light with a self-luminous phosphor, thereby improving the product value of the VFD or the image of the manufacturer.

Second, by turning on the logo of the back substrate side at the same time as the information display of the front substrate, it can be used as a backlight function.

Third, in the lead pin structure for applying the drive signal to the rear substrate, the drive signal is divided into a first portion drawn from the outside, and a second portion interposed between the first portion and the rear substrate, By adopting a structure in which the second portion is connected by welding or the like, it is possible to improve design freedom and contact stability of the lead pin structure.

Fourth, by adopting a structure in which the getter portion is fixed on the front substrate side and the getter coating is formed on the back substrate side, the getter coating is not observed on the front substrate side.

The invention is not limited to the examples described above and represented in the drawings. Many modifications to the above-described embodiments will be possible to those skilled in the art taught by the above-described embodiments by substitution, elimination, merging, rearrangement of steps, etc. within the scope and object of the present invention described in the following claims.

Claims (14)

In the double-sided light emission type VFD having a front substrate and a back substrate, A front substrate display unit having a first conductive layer formed in a predetermined information pattern on the top surface of the front substrate, a first phosphor layer coated on the first conductive layer, and a first grid electrode formed in a predetermined pattern on the first conductive layer. ; A rear substrate display having a second conductive layer having a predetermined logo pattern formed on the entire upper surface of the rear substrate, and a second phosphor layer coated on the second conductive layer; A plurality of line cathodes disposed between the front substrate display portion and the rear substrate display portion; A first lead part driving the front substrate display part; And And a second lead part for driving the back substrate display part. The display device of claim 1, wherein the second conductive layer of the rear substrate display unit is A double-sided fluorescent display tube, characterized in that the pattern is formed in the embossed on the basis of the outline of the logo. The display device of claim 1, wherein the second conductive layer of the rear substrate display unit is A double-sided fluorescent display tube, characterized in that the pattern is formed intaglio based on the outline of the logo. The display device of claim 1, wherein the second conductive layer of the rear substrate display unit is And a embossed conductive layer and an engraved conductive layer formed on the basis of the outline of the logo. The second phosphor layer of claim 4, wherein the second phosphor layer of the rear substrate display unit is And a phosphor layer having a different color is applied to the embossed conductive layer and the engraved conductive layer. The method of claim 1, wherein each of the lead pins in the second lead portion, A first portion directly connected to an external power source through the rear substrate display unit; And And a second portion having one end connected to the first portion and the other end connected to the second conductive layer. The method of claim 6, And the first portion and the second portion are connected by welding. The method of claim 6, The second portion is provided with a leaf spring, And one end of the second part is connected to the first part by welding, and the other end of the second part is a free end and is pressed onto the conductive layer by a spring force. The display panel of claim 1, wherein the rear substrate display unit And a second grid electrode formed in a predetermined pattern on the substrate around the second conductive layer. The method of claim 1, And a getter part fixedly fixed to an inner side of the front substrate and provided to form a getter film on the inner side of the rear substrate. A method of displaying a double-sided light emitting fluorescent display tube having a front substrate on which an information pattern is formed and a back substrate on which a predetermined logo pattern is embossed and engraved, (a) displaying an embossed logo pattern and / or an engraved logo pattern of the logo pattern; And (b) displaying the information pattern; and displaying a double-sided fluorescent display tube. The method of claim 11, wherein step (a) comprises: And displaying the embossed logo pattern or the engraved logo pattern selectively. The method of claim 11, wherein step (a) comprises: And displaying the embossed logo pattern or the intaglio logo pattern sequentially. The method of claim 11, wherein step (a) comprises: And displaying the embossed logo pattern and the intaglio logo pattern at the same time.