WO2008011021A2

WO2008011021A2 - Electroluminescent lamp

Info

Publication number: WO2008011021A2
Application number: PCT/US2007/016189
Authority: WO
Inventors: Michael Zeng; Jacky Chen; Ky Lee
Original assignee: Molex Incorporated
Priority date: 2006-07-18
Filing date: 2007-07-17
Publication date: 2008-01-24
Also published as: CN101110470A; WO2008011021A3; CN100568578C

Abstract

A combination of an electroluminescent lamp with a metal key panel comprises a substrate, an electroluminescent system printed on a side of the substrate, an insulating protection layer covering an external surface of the electroluminescent system, a first adhesive layer disposed on the insulating protection layer and a metal key panel adhered to the first adhesive layer and comprising a spacer and a plurality of metal keys, and further comprises a second adhesive layer disposed outside or over the metal key panel, wherein the substrate is made of a transparent material; the electroluminescent system is provided with a transparent conducting layer, an electroluminescent layer, a first dielectric layer, a rear electrode layer, a second dielectric layer and a second conducting layer sequentially from the side of the substrate to the outside; and light emitted by the electroluminescent layer transmits out passing through the transparent conducting layer and the substrate. The combination of the electroluminescent lamp with the metal key panel has the advantages of being resistant to damage, having reduced noise and easy to be adhered to a circuit board. The invention further provides the electroluminescent lamp and a manufacturing method thereof.

Description

ELECTROLUMINESCENT LAMP

FIELD OFTHE INVENTION

The present invention relates to an electroluminescent lamp and its combination with a metal key panel, as well as a method for manufacturing the electroluminescent lamp, and more particularly to an electroluminescent lamp and its combination with a metal key panel which are resistant to damage, provide reduced noise and are easy to be adhered to another electronic element, as well as a method for manufacturing the electroluminescent lamp.

BACKGROUND ART The electroluminescence technology, which was formerly used only in an aircraft cockpit, has become broadly used now for various civilian high technology consumer electronic products, such as mobile phones, pagers, wireless telephones, personal digital assistants, remote controllers and so on. Because electroluminescent lamps have characteristics such as small size, low weight, low temperature, low power consumption, non-flickering, uniform luminescence, etc., they are gradually replacing backlight means of conventional light emitting diodes (LEDs).

Please refer to Fig. 6 showing an electroluminescent system of a monolithic structure provided by U.S. Patent No. 5,856,029, which discloses an electroluminescent lamp comprising a rear electrode layer 16, a dielectric layer 15, an electroluminescent layer 14, a translucent electrode layer 13, a cover 12 and a bus bar 11. In an implementation, first, the rear electrode layer 16 is printed on a substrate 17 (such as a clothing) consisting of a textile fabric; then, the dielectric layer 15, the electroluminescent layer 14 and the translucent electrode layer 13 are sequentially printed thereon; next, the bus bar 11 is printed on the translucent electrode layer 13 in the form of a loop; and finally, the cover layer 12 is printed so as to be adhered to the substrate 17. However, since this electroluminescent lamp is directly printed on a final product such as an article of clothing, if the electroluminescent system is directly printed on an electronic product in a similar way, production would be seriously hindered because the electronic product may not readily withstand circumstances such as high temperature, baking and so on as well as other activities utilized during the printing process. Hence it is desirable to produce the electroluminescent system as a single product, then to transfer it to the electronic product.

Referring to Figs. 7 and 8 for another electroluminescent lamp, Chinese Patent Application No. 99125456.2 (corresponding to U.S. Patent Nos. 5,856,030 and 6,270,834) discloses a method for manufacturing an electroluminescent lamp. The electroluminescent lamp, printed on a transfer releasable paper 102, comprises a first envelope layer 104, an Indium Tin Oxide (ITO) layer 106, a front bus bar 107, an electroluminescent layer 108, a dielectric layer 110, a rear electrode layer 112 and a second envelope layer 114. The transfer releasable paper 102 is used as a substrate during printing, and the rest of the layers are sequentially printed on the transfer releasable paper 102, so the electroluminescent lamp can be produced as a single product.

However, during assembly of the electroluminescent lamp to an electronic product, adhering the electroluminescent lamp to the electronic product can be implemented only by coating an adhesive layer 116 on the second envelope layer 114 in advance, and adhering the adhesive layer 116, together with the electroluminescent lamp, to the electronic product, then peeling off the transfer releasable paper 102. That makes it inconvenient to use. Moreover, because this electroluminescent lamp is integrally formed by ink printing, its strength is relatively low, and it is prone to be damaged at the time of being stretched by an external force. On the other hand, when this electroluminescent lamp is applied to a mobile phone (not shown), it contacts keys of the mobile phone via an external surface of the first envelope layer 104, however, the first envelope layer 104 is formed by printing a layer of an insulating ink which has a relatively poor strength, and it is prone to be damaged after a long period of using cooperatively with the mobile phone.

Furthermore, the electroluminescent lamp, after being supplied with an alternating current (AC) for driving it to operate, has a current flowing in one direction at one moment, and at the next moment, the current will flow in a reverse direction. Such a periodic electromagnetic turbulence would result in the electroluminescent lamp generating some noise, and further, impairing comfort and quality of communication when the electroluminescent lamp is applied to a mobile phone.

SUMMARY OF THE INVENTION

A purpose of the invention is to provide an electroluminescent lamp which is resistant to damage, low-noised and easy to be adhered to another electronic element, and a method for manufacturing the electroluminescent lamp.

Another purpose of the invention is to provide a combination of an electroluminescent lamp with a metal key panel, which is resistant to damage, low-noised and easy to be adhered to a circuit board of a mobile phone.

For realizing the above purposes, the invention provides an electroluminescent lamp, comprising a substrate, an electroluminescent system printed on a side of the substrate and an insulating protection layer covering an external surface of the electroluminescent system; and further comprising a first adhesive layer and a releasable paper disposed outside of the insulating protection layer, wherein the substrate is a transparent polyester film; the electroluminescent system is provided with a transparent conducting layer, a bus bar, an electroluminescent layer, a first dielectric layer, a rear electrode layer, a second dielectric layer and a second conducting layer sequentially from the side of the substrate to the outside; and light emitted by the electroluminescent layer transmits outward passing through the transparent conducting layer and the substrate. The bus bar electrically communicates with the second conducting layer and the transparent conducting layer.

In addition, the invention provides a combination of an electroluminescent lamp with a metal key panel. The electroluminescent lamp and the metal key panel are produced, using the electroluminescent lamp according to the invention, by removing the releasable paper and adding a metal key panel, a second adhesive layer and releasable paper adhered to the first adhesive layer.

The invention further provides a method for manufacturing the electroluminescent lamp described above, comprising steps of: step 1 : providing a substrate of a transparent polyester film; step 2: printing an electroluminescent system to be laminated on a surface of the substrate, the step 2 further comprising steps of: step 2a: printing a transparent conducting layer on the substrate; step 2b: printing an electroluminescent layer to be laminated on the transparent conducting layer, the electroluminescent layer having a second opening disposed therein; step 2c: printing a first dielectric layer to be laminated on the electroluminescent layer, the first dielectric layer having also a second opening disposed correspondingly therein; step 2d: printing a rear electrode layer to be laminated on the first dielectric layer, the rear electrode layer having also a second opening disposed correspondingly therein; step 2e: printing a second dielectric layer to be laminated on the rear electrode layer, the second dielectric layer having a first opening and a second opening disposed therein; step 2f: printing a second conducting layer to be laminated on the second dielectric layer, the second conducting layer having also a first opening and a second opening disposed correspondingly therein; step 3: printing an insulating protection layer on the second conducting layer, the insulating protection layer, as an envelope layer of the electroluminescent system, enveloping the electroluminescent system sandwiched between the insulating layer and the substrate, and having also a first opening and a second opening disposed correspondingly therein; step 4: printing a first adhesive layer on the insulating protection layer, the first adhesive layer having also a first opening and a second opening disposed correspondingly therein.

The invention has the following advantageous effects: since the insulating protection layer of the electroluminescent, lamp according to the invention is adhered to the substrate so as to tightly seal the electroluminescent system sandwiched between the insulating protection layer and the substrate, no air, moisture, or dust can enter therein, and since it is unnecessary to peel off the substrate when assembling it to another product, the step of printing the envelope layer of the prior art can be omitted, resulting in simplifying the process and reducing the material used; since the electroluminescent lamp is provided with a first adhesive layer and a releasable paper, the electroluminescent lamp can be handled as an independent product for shipment and transportation, and when assembled, the electroluminescent lamp can be directly adhered to a circuit board of a mobile phone only after the releasable paper is easily and conveniently peeled off. The bottom surface of the electroluminescent lamp is a substrate consisting of a polyester film, as compared with the first envelope layer of the prior art formed by printing an insulating ink, durability is greatly enhanced, and additionally, the tensile strength of the electroluminescent lamp is improved. Furthermore, because the bus bar electrically communicates with the second conducting layer and the transparent conducting layer, the second conducting layer and the transparent conducting layer together form one electrode, while the rear electrode layer forms another electrode, such that two currents in the electroluminescent system flow in opposite or reverse directions at every moment and counteract each other. Thereby the impact of the electromagnetic turbulence is reduced, and the noise produced by the electroluminescent lamp is reduced. BRIEF DESCRIPTION OFTHE DRAWINGS

The organization and manner of the structure and operation of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings wherein like reference numerals identify like elements in which:

Fig. I is a perspective view of an electroluminescent lamp according to the invention;

Fig. 2 is a cross-sectional view of Fig. 1;

Fig. 3 is a schematic diagram of a metal key panel according to the invention; Fig. 4 is a cross-sectional view of a combination of an electroluminescent lamp and a metal key panel according to the invention;

Fig. 5 is a schematic diagram of the combination of the electroluminescent lamp and the metal key panel according to the invention in the case of being applied to a mobile phone; Fig. 6 is a cross-sectional view of an electroluminescent lamp of the prior art;

Fig. 7 is a perspective view of another electroluminescent lamp of the prior art; and

Fig. 8 is a cross-sectional view of Fig. 7.

DETAILED DESCRIPTION OFTHE PREFERRED EMBODIMENTS While this invention may be susceptible to embodiments in different forms, there is shown in the drawings and will be described herein in detail, a specific embodiment with the understanding that the present disclosure is to be considered an example of the principles of the invention, and is not intended to limit the invention to that as illustrated. Referring to Figs. 1 and 2, the invention provides an electroluminescent lamp which can be mounted to a backlight keyboard panel of a mobile phone or other electronic equipment.

The electroluminescent lamp comprises a transparent substrate 1 as well as an electroluminescent system (EL system) (not numbered) printed on an upper surface of the substrate 1, an insulating protection layer (dielectric layer) 3, a first adhesive layer 4 and a back adhesive protection layer 5.

The electroluminescent system is provided with a transparent conducting layer 21, a bus bar 22, an electroluminescent layer 23, a first dielectric layer 24, a rear electrode layer 25, a second dielectric layer 26 and a second conducting layer 27 sequentially from bottom to top from a side of the substrate 1. According to the present design, the respective layers of the electroluminescent system are printed on the substrate 1 to be laminated sequentially by means of screen printing. Of course, the printing can be performed by means of roller printing or other methods.

The substrate 1 is a piece of polyester (PET) film which is a soft and flexible film. The substrate 1 has a relatively high tensile strength, such that the electroluminescent lamp is not easy to be damaged. According to the present design, the substrate 1 is designed as colorless and transparent, but it can be certainly designed as, for example, red and transparent, blue and transparent, and so on, in accordance with practical requirements. The substrate 1 has a relatively high transmittance, such that the light emitted by the electroluminescent layer 23 can transmit easily through the substrate 1 and the transparent conducting layer 21.

The transparent conducting layer 21 is printed on an upper surface of the substrate 1, and is formed by printing a layer of transparent conductive ink such as Indium Tin Oxide (ITO) to be laminated on the substrate 1. The bus bar 22 is a loop of a filament printed on an upper surface of the transparent conducting layer 21 by using a silver-containing ink. The bus bar 22 electrically communicates with the transparent conducting layer 21, which can enhance electrical conductivity of the transparent conducting layer 21.

The electroluminescent layer 23 is formed by printing a mixture of a phosphor powder and an adhesive to be laminated on the bus bar 22. When an alternating current flows between the rear electrode layer 25 and the transparent conducting layer 21 of the electroluminescent lamp, the rear electrode layer 25 and the transparent conducting layer 21 will function as two electrodes of a capacitor, so the phosphor powder of the electroluminescent layer 23, under excitation of the alternating electric field, will emit light. The first dielectric layer 24 has a characteristic of relatively high insulation, and is formed by printing an insulating ink such as barium titanate to be laminated on the luminescent layer 23. In this design, the first dielectric layer 24 presents white color, and can reflect light emitted by the electroluminescent layer 23, such that the light emitted by the electroluminescent layer 23 can only transmit out passing through the transparent conducting layer 21 and the substrate 1.

The rear electrode layer 25 is formed by directly printing a layer of a non-transparent conductive ink such as silver ink or carbon ink to be laminated on the first dielectric layer 24.

The second dielectric layer 26 has a characteristic of relatively high insulation and is formed by printing an insulating ink such as barium titanate to be laminated on the rear electrode layer 25.

The second conducting layer 27 is formed by directly printing a layer of a non-transparent conductive ink such as silver ink or carbon ink to be laminated on the second dielectric layer 26. The second conducting layer 27 electrically communicates with the bus bar 22, such that an external power supply can supply power to the second conducting layer 27 via the electrically communicated bus bar 22. The electroluminescent system has a first opening 28 and a second opening 29 disposed therein. The first opening 28 communicates with the rear electrode layer 25 after passing through the first adhesive layer 4, the insulating protection layer 3, the second conducting layer 27 and the second dielectric layer 26. The second opening 29 communicates with the bus bar 22 after passing through the first adhesive layer 4, the insulating protection layer 3, the second conducting layer 27, the second dielectric layer 26, the rear electrode layer 25, the first dielectric layer 24 and the electroluminescent layer 23.

The insulating protection layer 3 is formed by printing a waterproof and dustproof ink (such as polyurethane) on the second conducting layer 27. The insulating protection layer 3, as an envelope layer of the electroluminescent system, is adhered to the substrate 1, so as to tightly seal the electroluminescent system between the insulating protection layer and the substrate, such that air, moisture, or dust which reduces the luminescent life of the lamp, is prevented from entering the electroluminescent lamp. The first adhesive layer 4 is a layer of self-adhesive coated on the insulating protection layer 3.

In this design, the back adhesive protection layer 5 is a releasable paper. The back adhesive protection layer 5 is disposed on the first adhesive layer 4, for preventing the first adhesive layer 4 from being contaminated by the environment. When mounted, the electroluminescent lamp can be adhered to another electronic element such as a metal key panel, only after the releasable paper is peeled off to expose the first adhesive layer 4.

Referring to Figs. 3 to 5, the invention further provides a combination of the electroluminescent lamp with a metal key panel, which can be mounted on a circuit board of a mobile phone or on other personal electronic devices (not shown). The combination of the electroluminescent lamp with the metal key panel is produced, using the electroluminescent lamp described above, by removing the back adhesive protection layer 5, and adding a metal key panel 6, a second adhesive layer 7 and a back adhesive protection layer 8.

The metal key panel 6 comprises a spacer 62 and a plurality of metal keys 66. A plurality of circular shaped receiving grooves 64 are opened in the spacer 62. These receiving grooves 64 are connected by a plurality of air escaping channels 65. These metal keys 66 are metal plates having a dome shape, and are respectively received within theses receiving grooves 64. The air expelled at the time of pressuring the metal keys 66 can be discharged via the air escaping channels 65, so as to improve hand feeling at the time of pressuring. The second adhesive layer 7 is a layer of self-adhesive directly coated on a surface of the spacer 62.

The back adhesive protection layer 8 is disposed on the second adhesive layer 7. In this design, the back adhesive protection layer 8 is a releasable paper. The back adhesive protection layer 8 is disposed outside of the second adhesive layer 7, so as to prevent the second adhesive layer 7 from being contaminated by the environment.

The combination of the electroluminescent lamp with the metal key panel has a first opening 28 and a second opening 29 disposed therein. The first opening 28 communicates with the rear electrode layer 25 after passing through the second adhesive layer 7, the spacer 62, the first adhesive layer 4, the insulating protection layer 3, the second conducting layer 27 and the second dielectric layer 26. And the second opening 29 communicates with the bus bar 22 after passing through the second adhesive layer 7, the spacer 62, the first adhesive layer 4, the insulating protection layer 3, the second conducting layer 27, the second dielectric layer 26, the rear electrode layer 25, the first dielectric layer 24 and the electroluminescent layer 23. In use, the combination of the electroluminescent lamp with the metal key panel can be adhered to a circuit board 9 of a mobile phone only after the back adhesive protection layer 8 is peeled off to expose the second adhesive layer 7. Two conducting contacts 92, 94 on the circuit board 9 respectively extend into the first opening 28 and the second opening 29, so as to electrically communicate with the rear electrode layer 25 and the bus bar 22 directly. Because the bus bar 22 electrically communicates with the second conducting layer 27 and the transparent conducting layer 21, the second conducting layer 27 and the transparent conducting layer 21, which electrically communicate with the conducting contact 94, together form one electrode of a capacitor; and the rear electrode layer 25, which electrically communicates with the conducting contact 92, forms another electrode of the capacitor, such that the second conducting layer 27 and the transparent conducting layer 21 form two capacitors, respectively with the rear electrode layer 25. When the circuit board 9 supplies an alternating current for driving the electroluminescent lamp to emit light, at one moment, currents flow from the second conducting layer 27 and transparent conducting layer 21, respectively and simultaneously, to the rear electrode layer 25; and at the next moment, currents flow from the rear electrode layer 25 to the second conducting layer 27 and the transparent conducting layer 21, respectively, such that there are always two currents in the electroluminescent system flowing in opposite or reverse directions at every moment, and counteracting each other. Thereby a reduction in the impact of the electromagnetic turbulence and the noise produced by the electroluminescent lamp is obtained. The bottom surface of the combination of the electroluminescent lamp with the metal key panel according to the invention is a substrate 1 consisting of a polyester film. The substrate 1 has a relatively high mechanical strength, and therefore has a relatively long service life when used cooperatively with the keys 122 of the mobile phone. The electroluminescent lamp and its combination with the metal key panel can be handled as an independent product for shipment and transportation, due to the arrangement of the back adhesive protection layers 5 and 8. And in use, adhering can be performed only after the back adhesive protection layers 5 and 8 are peeled off, easily and conveniently.

According to the invention, if the electrical conductivity of the transparent conducting layer 21 is relative high, the bus bar 22 can be omitted, and the transparent conducting layer 21 electrically communicates with the second conducting layer 27 instead. In this way, the same effects of the invention can be achieved.

The invention also provides a method for manufacturing the above electroluminescent lamp, comprising the following steps: step 1 : providing a substrate 1 of a transparent polyester film; step 2: printing an electroluminescent system to be laminated on an upper surface of the substrate 1, the step 2 further comprising the following steps: printing a transparent conducting layer 21 to be laminated on the substrate 1 by using an electrically conductive ink of Indium Tin Oxide; printing a loop of bus bar 22 on the transparent conducting layer 21 by using a silver ink; printing an electroluminescent layer 23 to be laminated on the bus bar 22 by using a mixture of a phosphor powder and an adhesive, the electroluminescent layer 23 having a second opening 29 which communicates with the bus bar 22; printing a first dielectric layer 24 to be laminated on the electroluminescent layer 23 by using an insulating ink such as barium titanate, the first dielectric layer 24 having a second opening 29 also correspondingly disposed therein; printing a rear electrode layer 25 to be laminated on the first dielectric layer 24 by using a silver ink or carbon ink, the rear electrode layer 25 having a second opening 29 being also correspondingly disposed therein; printing a second dielectric layer 26 to be laminated on the rear electrode layer 25 by using an insulating ink such as barium titanate, the second dielectric layer 26 having a first opening 28 and a second opening 29 correspondingly disposed therein; printing a second conducting layer 27 to be laminated on the second dielectric layer 26 by using a silver ink or carbon ink, the second conducting layer 27 having a first opening 28 and a second opening 29 being also correspondingly disposed therein; step 3: printing an insulating protection layer 3 on the second conducting layer 27, the insulating protection layer 3, as an envelope layer of the electroluminescent system, enveloping the electroluminescent system to the substrate 1, and having also a first opening 28 and a second opening 29 disposed correspondingly therein; step 4: applying a first adhesive layer 4 on the insulating protection layer 3, the first adhesive layer 4 being a layer of self-adhesive coated on the insulating protection layer 3 and having also a first opening 28 and a second opening 29 disposed correspondingly therein; and step 5: further laying a back adhesive protection layer 5 on the first adhesive layer 4, so as to prevent the first adhesive layer 4 from being contaminated by the environment.

Moreover, in manufacturing the combination of the electroluminescent lamp with the metal key panel described above, in addition to the above steps 1 to 4 for manufacturing the electroluminescent lamp, the following steps are further comprised: step 5: providing a metal key panel 6 comprising a spacer 62 having a plurality of receiving grooves 64 opened therein and a plurality of metal keys 66 being correspondingly received in receiving grooves 64 of the spacer, wherein a second adhesive layer 7 is disposed on a side of the spacer 62 of the metal key panel 6, a first opening 28 and a second opening 29 being also correspondingly disposed in the spacer 62 and second adhesive layer 7, a back adhesive protection layer 8 is further disposed outside of the second adhesive layer 7 for preventing the second adhesive layer 7 from being contaminated by the environment; step 6: adhering the other side of the spacer 62 of the metal key panel 6 to the first adhesive layer 4 of the electroluminescent lamp, so as to form a combination of the electroluminescent lamp with the metal key panel. While a preferred embodiment of the invention is shown and described, it is envisioned that those skilled in the art may devise various modifications without departing from the spirit and scope of the foregoing description and the appended claims.

Claims

1. An electroluminescent lamp, comprising a substrate, an electroluminescent system printed on a side of the substrate and an insulating protection layer covering an external surface of the electroluminescent system, characterized by further comprising a first adhesive layer disposed outside of the insulating protection layer, wherein the substrate is made of a transparent material; the electroluminescent system is provided with a transparent conducting layer, an electroluminescent layer, a first dielectric layer, a rear electrode layer, a second dielectric layer and a second conducting layer sequentially from the side of the substrate to outside; and light emitted by the electroluminescent layer transmits out passing through the transparent conducting layer and the substrate.

2. The electroluminescent lamp according to claim 1 , characterized by further comprising a back adhesive protection layer disposed outside of the first adhesive layer for preventing the first adhesive layer from being contaminated by the environment.

3. The electroluminescent lamp according to claim 2, characterized by the first adhesive layer being a layer of self-adhesive coated on the insulating protection layer; and the back adhesive protection layer being a releasable paper.

4. The electroluminescent lamp according to claim 1 , characterized by at least one bus bar, which electrically communicates with the transparent conducting layer, being further disposed between the transparent conducting layer and the electroluminescent layer, so as to enhance the electrical conductivity of the transparent conducting layer.

5. The electroluminescent lamp according to claim 4, characterized by having at an external surface of the electroluminescent lamp a first opening and a second opening, wherein the first opening communicates with the rear electrode layer after passing through the first adhesive layer, the insulating protection layer, the second conducting layer and the second dielectric layer; and the second opening communicates with the bus bar after passing through the first adhesive layer, the insulating protection layer, the second conducting layer, the second dielectric layer, the rear electrode layer, the first dielectric layer and the electroluminescent layer.

6. The electroluminescent lamp according to claim 5, characterized by an external power supply being extended respectively into the first opening and the second opening so as to electrically communicate with the rear electrode layer and the transparent conducting layer, for supplying power to the electroluminescent lamp.

7. The electroluminescent lamp according to claim 6, characterized by the bus bar also electrically communicating with the second conducting layer, such that the external power supply can supply power to the second conducting layer via the bus bar.

8. The electroluminescent lamp according to claim 1 , characterized by the substrate being a polyester film.

9. A method for manufacturing the electroluminescent lamp according to claim 1, characterized by comprising steps of: step 1 : providing a substrate of a transparent polyester film; step 2: printing an electroluminescent system to be laminated on a surface of the substrate, the step 2 further comprising steps of: step 2a: printing a transparent conducting layer on the substrate; step 2b: printing an electroluminescent layer to be laminated on the transparent conducting layer, the electroluminescent layer having a second opening disposed therein; step 2c: printing a first dielectric layer to be laminated on the electroluminescent layer, the first dielectric layer having also a second opening disposed correspondingly therein; step 2d: printing a rear electrode layer to be laminated on the first dielectric layer, the rear electrode layer having also a second opening disposed correspondingly therein; step 2e: printing a second dielectric layer to be laminated on the rear electrode layer, the second dielectric layer having a first opening and a second opening disposed therein; step 2f: printing a second conducting layer to be laminated on the second dielectric layer, the second conducting layer having also a first opening and a second opening disposed correspondingly therein; step 3: printing an insulating protection layer on the second conducting layer, the insulating protection layer, as an envelope layer of the electroluminescent system, enveloping the electroluminescent system sandwiched between the insulating layer and the substrate, and having also a first opening and a second opening disposed correspondingly therein; step 4: printing a first adhesive layer on the insulating protection layer, the first adhesive layer having also a first opening and a second opening disposed correspondingly therein.

10. The method for manufacturing the electroluminescent lamp according to claim 9, characterized by, between the steps 2a and 2b, further comprising a step of printing at least one bus bar on the transparent conducting layer, wherein the second opening communicates with the bus bar.

11. The method for manufacturing the electroluminescent lamp according to claim 9, characterized by the first adhesive layer being a layer of self-adhesive.

12. The method for manufacturing the electroluminescent lamp according to claim 11, characterized by, after the step 4, further comprising a step 5 of additionally disposing a back adhesive protection layer on the first adhesive layer for preventing the first adhesive layer from being contaminated by the environment.

13. The method for manufacturing the electroluminescent lamp according to claim 9, characterized by the transparent conducting layer being formed by printing an electrically conductive ink of Indium Tin Oxide; the electroluminescent layer being formed by printing a mixture of a phosphor powder and an adhesive; the first dielectric layer being formed by printing an insulating ink of barium titanate; the rear electrode layer being formed by printing a layer of non-transparent silver ink or carbon ink; the second dielectric layer being formed by printing an insulating ink of barium titanate; the second conducting layer being also formed by printing a layer of non-transparent silver ink or carbon ink; and the insulating protection layer being formed by printing a polyurethane.

14. A combination of an electroluminescent lamp with a metal key panel, comprising a substrate, an electroluminescent system printed on a side of the substrate, an insulating protection layer covering an external surface of the electroluminescent system, a first adhesive layer disposed on the insulating protection layer and a metal key panel adhered to the first adhesive layer and comprising a spacer having a plurality of receiving grooves opened therein and a plurality of metal keys correspondingly received in the receiving grooves of the spacer, characterized by further comprising a second adhesive layer disposed at outside of the metal key panel, wherein the substrate is made of a transparent material; the electroluminescent system is provided with a transparent conducting layer, an electroluminescent layer, a first dielectric layer, a rear electrode layer, a second dielectric layer and a second conducting layer sequentially from the side of the substrate to outside; and light emitted by the electroluminescent layer transmits out passing through the transparent conducting layer and the substrate.

15. The combination of the electroluminescent lamp with the metal key panel according to claim 14, characterized by further comprising a back adhesive protection layer disposed at outside of the second adhesive layer for preventing the second adhesive layer from being contaminated by the environment.

16. The combination of the electroluminescent lamp with the metal key panel according to claim 15, characterized by the second adhesive layer being a layer of self-adhesive and the back adhesive protection layer being a releasable paper, wherein the combination of the electroluminescent lamp with the metal key panel can be adhered to a circuit board only after the releasable paper is peeled off.

17. The combination of the electroluminescent lamp with the metal key panel according to claim 14, characterized by at least one bus bar, which electrically communicates with the transparent conducting layer, being further disposed between the transparent conducting layer and the electroluminescent layer, so as to enhance the electrical conductivity of the transparent conducting layer.

18. The combination of the electroluminescent lamp with the metal key panel according to claim 17, characterized by being provided with a first opening and a second opening, wherein the first opening communicates with the rear electrode layer after passing through the second adhesive layer, the spacer, the first adhesive layer, the insulating protection layer, the second conducting layer and the second dielectric layer; and the second opening communicates with the bus bar after passing through the second adhesive layer, the spacer, the first adhesive layer, the insulating protection layer, the second conducting layer, the second dielectric layer, the rear electrode layer, the first dielectric layer and the electroluminescent layer.

19. The combination of the electroluminescent lamp with the metal key panel according to claim 18, characterized by an external power supply being extended respectively into the first opening and the second opening so as to electrically communicate with the rear electrode layer and the transparent conducting layer, for supplying power to the electroluminescent lamp.

20. The combination of the electroluminescent lamp with the metal key panel according to claim 19, characterized by the bus bar also electrically communicating with the second conducting layer, such that the external power supply can supply power to the second conducting layer via the bus bar.

21. The combination of the electroluminescent lamp with the metal key panel according to claim 14, characterized by the substrate being a polyester film.