TWI468775B - Electroluminescent display panel and method of making the same - Google Patents

Description

Electroluminescent display and manufacturing method thereof

The present invention relates to an electroluminescent display and a method of fabricating the same, and more particularly to a double-sided electroluminescent display and a method of fabricating the same.

With the advancement of technology and the evolution of electronic products, the market demand for flat display panels is increasing. The traditional liquid crystal display (LCD) has gradually failed to meet the requirements of viewing angle, speed, contrast, brightness and the like. Therefore, the Organic Electroluminescent Display Panel has been developed by the industry to replace the traditional liquid crystal display. With the use of Thin Film Transistor (TFT), active organic electroluminescent display has wide viewing angle, fast response, high contrast, high efficiency, self-illumination, high brightness, low driving voltage, full color, etc. Advantages, in line with the needs of the next generation of flat panel displays.

Since the organic electroluminescent display has the above advantages, it has been widely used in consumer electronic products such as mobile phones, digital cameras, personal digital assistants, notebook computers, and amusement instruments. As the display function of electronic products progresses from single-sided display to double-sided display, how to make the organic electroluminescent display can be displayed on both sides is also a topic and challenge of current industrial design.

Please refer to Figure 1. Figure 1 is a schematic diagram of a pixel of a conventional organic electroluminescent display. As shown in FIG. 1, the conventional organic electroluminescent display 100 includes a lower substrate 102, a thin film transistor (TFT) 108, a first protective layer 110, a second protective layer 116, and an organic light emitting diode (OLED) 124. , the upper substrate 126, and the sealant 128. The material of the anode (Anode) 114 of the organic light-emitting diode 124 is a transparent and indium tin oxide (ITO), and the cathode 122 is made of a thin layer of silver (Ag). )composition. Since both indium tin oxide and thin silver have a light transmitting property, the effect of double-sided light emission can be achieved. However, silver also partially reflects the light emitted from the light-emitting layer 120 of the organic light-emitting diode 124 to the other surface, resulting in the brightness of the conventional organic electroluminescent display 100 on the front side (upper side) being lower than the reverse side (lower side). The situation happened.

Please refer to Figures 2A and 2B again. FIG. 2A is a schematic view showing a front side (upper side) image of a conventional organic electroluminescent display when performing double-sided transparent display, and FIG. 2B is a reverse view of a conventional organic electroluminescent display when performing double-sided transparent display ( The lower side is a schematic representation of the image presented. As shown in FIGS. 2A and 2B, due to the double-sided transparent display, the front (upper side) and reverse (lower) images are opposite, which imposes application limitations. Therefore, the problem that the brightness of the front and back sides is different from the image is urgently needed to be overcome and improved.

One of the objects of the present invention is to provide an electroluminescent display that solves the problem that the brightness of the front and back sides of the conventional organic electroluminescent display is opposite to that of the image when performing double-sided display.

To achieve the above object, the present invention provides an electroluminescent display comprising: a first display device; a second display device; and a controllable optical switch unit. The first display device comprises a first light emitting element and a first thin film transistor, and the second display device comprises a second light emitting element and a second thin film transistor. The configurable optical switch unit is disposed between the first display device and the second display device, and the steerable optical switch unit has a light transmitting state and an opaque state.

The present invention will be further understood by those of ordinary skill in the art to which the present invention pertains. .

Please refer to Figure 3. 3 is a schematic view of a first display device of an electroluminescent display according to a first preferred embodiment of the present invention. As shown in FIG. 3, the lower substrate 202 (for example, a flexible substrate, a glass substrate, or a quartz substrate) has a driving element region 204 and a light transmitting region 206. The first thin film transistor 208 is located in the driving element region 204 of the lower substrate 202, wherein the first thin film transistor 208 can be an amorphous germanium thin film transistor, a low temperature polycrystalline germanium thin film transistor or a high temperature polycrystalline germanium thin film transistor. . The first protective layer 210 is located in the driving element region 204 and the transparent region 206 of the lower substrate 202, and the first protective layer 210 has an opening 212 exposing a drain electrode of the first thin film transistor 208 (not shown). . A conductive layer 214 is disposed on a portion of the first protective layer 210, and the conductive layer 214 is electrically connected to the first thin film transistor 208 through the opening 212, and the conductive layer 214 is used as the first light emitting element 224 of the present invention. For the anode of (for example, the first organic light-emitting diode). The second protective layer 216 is on the first protective layer 210 and the conductive layer 214, and the second protective layer 216 has an opening 218 in at least a portion of the second protective layer 216 of the driving element region 204. The light-emitting layer 220 and the electrode layer 222 are sequentially disposed on the conductive layer 214 and the second protective layer 216. The light-emitting layer 220 may be different in color depending on the color of the pixel to be displayed (for example, red light, green light, blue light). Or a white light emitting material, and the electrode layer 222 can be used as a cathode of the first light emitting element 224. The upper substrate 226 (for example, a glass upper cover) and the lower substrate 202 are sealed by a sealant 228 to constitute a first display device 230.

Please refer to Figure 4. 4 is a schematic view of a second display device of an electroluminescent display according to a first preferred embodiment of the present invention. As shown in FIG. 4, the second display device 330 can be fabricated by using a photomask (that is, a photomask corresponding to the image) commensurate with the reticle design used to fabricate the first display device 230. The second display device 330 includes a lower substrate 302 (having a driving element region 304 and a light transmitting region 306), a second thin film transistor 308, a first protective layer 310, an opening 312, and a conductive layer 314 (through the opening 312 and the second The thin film transistor 308 is electrically connected), the second protective layer 316, the opening 318 (located in at least part of the second protective layer 316 of the driving element region 304), the light emitting layer 320 and the electrode layer 322 (located in the conductive layer 314 and the second protection) The upper substrate 326 and the sealant 328, wherein the conductive layer 314, the light emitting layer 320 and the electrode layer 322 constitute the second light emitting element 324.

Please refer to Figure 5. Figure 5 is a schematic view of an electroluminescent display of the first preferred embodiment of the present invention. As shown in FIG. 5, the driving element region 204 and the light transmitting region 206 of the first display device 230 correspond to the driving device region 304 and the light transmitting region 306 of the second display device 330, respectively. In addition, the tunable optical switch unit 430 is disposed between the first display device 230 and the second display device 330, and the lower substrate 202 of the first display device 230 and the lower substrate 302 of the second display device 330 are sealed 428 Sealing, that is, the electroluminescent display 200 of the first preferred embodiment of the present invention. In this embodiment, the conductive layer 214 can serve as the anode of the first light-emitting element 224 (eg, the first organic light-emitting diode), and the conductive layer 314 can serve as the second light-emitting element 324 (eg, the second organic light-emitting diode) For the anode of the body). Similarly, the electrode layer 222 can be used as the cathode of the first light-emitting element 224, and the electrode layer 322 can be used as the cathode of the second light-emitting element 324.

The electroluminescent display 200 of the embodiment may include a control unit 450, and the control unit 450 is electrically connected to the regulatable optical switch unit 430. The control unit 450 can be a power switch or an inductive switch for controlling the adjustable optical switch unit 430. In addition, the modulating optical switch unit 430 can include an electro-modulation device such as a liquid crystal device. The liquid crystal device includes a liquid crystal layer 440, a first electrode 431 and a second electrode 432, and the first electrode 431 and the second electrode 432 are respectively located in the liquid crystal. Both sides of layer 440. The electroluminescent display 200 can include a first polarizer 410 and a second polarizer 420, wherein the first electrode 431 is disposed between the liquid crystal layer 440 and the first polarizer 410, and the second electrode 432 is disposed on the liquid crystal layer 440. Between the second polarizer 420 and the second polarizer 420. In this embodiment, the first polarizer 410 can be disposed between the first electrode 431 and the lower substrate 202 of the first display device 230, and the second polarizer 420 can be disposed on the second electrode 432 and the second display device 330. Between the lower substrate 302, but not limited thereto. For example, the first polarizer 410 can also be disposed between the cathode of the first light-emitting element 224 (electrode layer 222) and the upper substrate 226 of the first display device 230, or placed on the upper substrate 226 of the first display device 230. Outside, or any other suitable location. Similarly, the second polarizer 420 may be disposed between the cathode (electrode layer 322) of the second light emitting element 324 and the upper substrate 326 of the second display device 330, or disposed outside the upper substrate 326 of the second display device 330. Or any other suitable location. In addition, the tunable optical switch unit 430 is not limited to an electro-modulation device, but may also include a photo-modulation device, a mechanical switch, or other device that can control light penetration. The electroluminescent display 200 of the present embodiment can include a signal unit 460, and the signal unit 460 is electrically connected to the first display device 230 and the second display device 330 for providing driving signals to the first display device 230 and the second display. Device 330.

In order to improve the problem that the brightness of the front and back sides of the conventional organic electroluminescent display is opposite to that of the image when performing double-sided display, the first light-emitting element 224 of the electroluminescent display 200 of the present embodiment is taken as an example in FIG. Placed above the first thin film transistor 208 and overlapping each other, the second light emitting elements 324 are placed over the second thin film transistors 308 and overlap each other, and the conductive layers (anodes) 214, 314 are oxidized by a conventional transparent conductive material, such as Indium tin (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO) or a combination thereof, changed to a thicker metal material (opaque) such as aluminum (Al), silver (Ag) or a combination thereof However, the electrode layer (cathode) 222, 322 is a thin metal material (light transmitting), such as aluminum (Al), silver (Ag) or a combination thereof, but is not limited thereto. In other words, the conductive layers (anodes) 214, 314 comprise reflective conductive layers, and the electrode layers (cathodes) 222, 322 comprise transparent electrode layers, such that the light that illuminates the light-emitting layers 220, 320 toward the conductive layers (anodes) 214, 314 is reflected to the other side, and mostly penetrates the electrodes The layers (cathodes) 222, 322 can avoid the problem of different brightness of the front and back sides of the conventional organic electroluminescent display when performing double-sided display, and can still maintain the transmittance of the entire display. In addition, because of the two-sided symmetrical design, when the two-sided display is displayed, the user can choose to display the same picture or different pictures, which solves the problem that the conventional organic electroluminescent display has opposite sides on both sides of the double-sided display.

Please refer to Figures 6A to 6F. 6A to 6F are schematic views of the electroluminescent display of the first preferred embodiment of the present invention in different display states. If the display is to be transparent, the tunable optical switch unit 430 can be adjusted to a light transmitting state, as shown in FIGS. 6A to 6C. To be precise, if the front side single-sided light-transparent display is to be performed, the first display device 230 can be used to provide the first image L1, and the controllable optical switch unit 430 can be adjusted to the light-transmitting state (as shown in FIG. 6A). If the reverse side single-sided light-transparent display is to be performed, the second display device 330 can be used to provide the second image L2, and the controllable optical switch unit 430 can be adjusted to a light-transmitting state (as shown in FIG. 6B); If the double-sided illumination transparent display is to be performed, the first display device 230 and the second display device 330 can be used to provide the first image L1 and the second image L2, respectively, and the adjustable light switch unit 430 is adjusted to be transparent. Status (as shown in Figure 6C). In addition, if the transparent display is not required, the controllable optical switch unit 430 is adjusted to an opaque state, as shown in FIGS. 6D to 6F. To be precise, if the front side single-sided illumination non-transparent display is to be performed, the first display device 230 can be used to provide the first image L1, and the controllable optical switch unit 430 can be adjusted to the opaque state (eg, FIG. 6D). If the reverse side single-sided illumination non-transparent display is to be performed, the second display device 330 can be used to provide the second image L2, and the controllable optical switch unit 430 can be adjusted to be opaque (eg, FIG. 6E). If the double-sided illumination non-transparent display is to be performed, the first display device 230 and the second display device 330 can be used to provide the first image L1 and the second image L2, respectively, and the adjustable optical switch unit is provided. 430 is adjusted to be opaque (as shown in Figure 6F). Therefore, by controlling the controllable optical switch unit 430, whether it is a transparent display (single-sided light-transparent display, double-sided light-transparent display, double-sided non-lighting) or non-transparent display (single-sided display, double-sided display) ), can be easily reached.

The electroluminescent display 200 of the present embodiment may have different implementation modes. For the sake of simplicity of description and ease of comparison, in the following embodiments, the same components are denoted by the same symbols, and only for different places. Detailed. Please refer to Figure 7. Figure 7 is a schematic view showing another embodiment of the electroluminescent display of the first preferred embodiment of the present invention. As shown in FIG. 7, the electroluminescent display 200' of the present embodiment includes a first signal unit 470 and a second signal unit 480. The first signal unit 470 is electrically connected to the first display device 230 for providing a driving signal. The first display device 230 is electrically connected to the second display device 330 for providing a driving signal to the second display device 330.

As can be seen from the above, the electroluminescent display of the first preferred embodiment places the first illuminating element 224 above the first thin film transistor 208 and overlaps each other, and the second illuminating element 324 is placed in the second thin film transistor 308. Above and overlap each other. The electrode layers (cathodes) 222, 322 are selected from relatively thin metal materials (e.g., aluminum, silver, or combinations thereof), and the conductive layers (anodes) 214, 314 are replaced with thicker metal materials (e.g., aluminum, silver, or combinations thereof). In other words, the conductive layers (anodes) 214, 314 comprise reflective conductive layers, and the electrode layers (cathodes) 222, 322 comprise transparent electrode layers, such that the light that illuminates the light-emitting layers 220, 320 toward the conductive layers (anodes) 214, 314 is reflected to the other side, and most of the electrodes are penetrated Layer (cathode) 222, 322. In this way, the conventional organic electroluminescent display can be prevented from having different brightness on the front and back sides when performing double-sided display, and the transmittance of the entire display can be maintained. In addition, because of the two-sided symmetrical design, when the two-sided display is displayed, the user can choose to display the same picture or different pictures, which solves the problem that the conventional organic electroluminescent display has opposite sides on both sides of the double-sided display. At the same time, by controlling the controllable optical switch unit 430, whether it is transparent display (single-sided light-transparent display, double-sided light-transparent display, double-sided non-lighting) or non-transparent display (single-sided display, double-sided display Display), can be easily achieved.

Please refer to Figure 8. Figure 8 is a schematic view of an electroluminescent display of a second preferred embodiment of the present invention. As shown in FIG. 8 , the electroluminescent display 500 of the present embodiment includes a first display device 530 and a second display device 630 , and the adjustable optical switch unit 730 is disposed on the first display device 530 and the second display device 630 . between. The lower substrate 502 of the first display device 530 is sealed with the lower substrate 602 of the second display device 630 by the sealant 728. The first display device 530 includes a lower substrate 502 (having a driving element region 504 and a light transmitting region 506), a first thin film transistor 508, a first protective layer 510, an opening 512, and a conductive layer 514 (through the opening 512 and the first The thin film transistor 508 is electrically connected), the second protective layer 516, the opening 518 (in at least part of the second protective layer 516 of the light transmitting region 506), the light emitting layer 520 and the electrode layer 522 (located in the conductive layer 514 and the second protection) The upper substrate 526, and the encapsulant 528, wherein the conductive layer 514, the light emitting layer 520 and the electrode layer 522 constitute a first light emitting element 524. In addition, the second display device 630 includes a lower substrate 602 (having a driving element region 604 and a light transmitting region 606 thereon), a second thin film transistor 608, a first protective layer 610, an opening 612, and a conductive layer 614 (through the opening 612 is electrically connected to the second thin film transistor 608), the second protective layer 616, the opening 618 (in at least part of the second protective layer 616 of the transparent region 606), the light emitting layer 620 and an electrode layer 622 (located in the conductive layer) 614 and the second protective layer 616), the upper substrate 626, and the encapsulant 628, wherein the conductive layer 614, the light emitting layer 620 and the electrode layer 622 constitute the second light emitting element 624. The driving element region 504 and the light transmitting region 506 of the first display device 530 correspond to the driving element region 604 and the light transmitting region 606 of the second display device 630, respectively.

The electroluminescent display 500 of the present embodiment can include a control unit 750, and the control unit 750 is electrically connected to the adjustable optical switch unit 730. The control unit 750 can be a power switch or an inductive switch for controlling the adjustable optical switch unit 730. In addition, the configurable optical switch unit 730 can include an electro-modulation device such as a liquid crystal device. The liquid crystal device includes a liquid crystal layer 740, a first electrode 731 and a second electrode 732, and the first electrode 731 and the second electrode 732 are respectively located in the liquid crystal. Both sides of layer 740. The electroluminescent display 500 can include a first polarizer 710 and a second polarizer 720, wherein the first electrode 731 is disposed between the liquid crystal layer 740 and the first polarizer 710, and the second electrode 732 is disposed on the liquid crystal layer 740. Between the second polarizer 720 and the second polarizer 720. In this embodiment, the first polarizer 710 can be disposed between the first electrode 731 and the lower substrate 502 of the first display device 530, and the second polarizer 720 can be disposed on the second electrode 732 and the second display device 630. Between the lower substrate 602, but not limited thereto. For example, the first polarizer 710 may also be disposed between the cathode (electrode layer 522) of the first light-emitting element 524 and the upper substrate 526 of the first display device 530, or placed on the upper substrate 526 of the first display device 530. Outside, or any other suitable location. Similarly, the second polarizer 720 may be disposed between the cathode (electrode layer 622) of the second light-emitting element 624 and the upper substrate 626 of the second display device 630, or disposed outside the upper substrate 626 of the second display device 630. Or any other suitable location. In addition, the tunable optical switch unit 730 is not limited to an electro-modulation device, but may also include a photo-modulation device, a mechanical switch, or other device that can control light penetration. The electroluminescent display 500 of the present embodiment can include a signal unit 760, and the signal unit 760 is electrically connected to the first display device 530 and the second display device 630 for providing a driving signal to the first display device 530 and the second display. Device 630.

In this embodiment, the first light-emitting element 524 is placed above the light-transmissive region 506, and does not overlap with the first thin-film transistor 508, and the second light-emitting element 624 is placed above the light-transmitting region 606, not with the second film. The transistors 608 overlap each other. The conductive layer (anode) 514, 614 is made of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO) or a combination thereof, but not limited thereto, the electrode layer (cathode) 522, 622 A thinner metal material such as aluminum (Al), silver (Ag) or a combination thereof is used, but not limited thereto. In other words, in the present embodiment, the conductive layers (anodes) 514, 614 comprise transparent conductive layers, the electrode layers (cathodes) 522, 622 comprise transparent electrode layers, and the anode and cathode systems have light transmitting properties. At this time, if the first display device 530 and the second display device 630 do not provide images, and the adjustable light switch unit 730 is adjusted to a light transmitting state, the electroluminescent display 500 can be made transparent (double-sided non-lighting) ).

Please refer to pictures 9A to 9C. 9A to 9C are schematic views showing the electroluminescent display of the second preferred embodiment of the present invention in different display states. If the transparent display is not required, the tunable optical switch unit 730 is adjusted to an opaque state, as shown in FIGS. 9A to 9C. To be precise, if the front side single-sided illumination non-transparent display is to be performed, the first display device 530 can be used to provide the first image L1, and the controllable optical switch unit 730 can be adjusted to the opaque state (eg, FIG. 9A). As shown, the first image L1 is emitted from the front surface of the electroluminescent display 500, but the first image L1 that is advanced toward the adjustable optical switch unit 730 is blocked; if the reverse side is illuminated, the non-transparent The second display device 630 can be used to provide the second image L2, and the adjustable light switch unit 730 can be adjusted to the opaque state (as shown in FIG. 9B), and the second image L2 is powered by the second image. The opposite side of the excitation light display 500 is emitted, but the second image L2 that is advanced toward the steerable optical switch unit 730 is blocked; if the double-sided illuminating non-transparent display is to be performed, the first display device 530 can be simultaneously utilized. The two display devices 630 respectively provide the first image L1 and the second image L2, and adjust the adjustable light switch unit 730 to an opaque state (as shown in FIG. 9C), and the first image L1 and the second image at this time. L2 will be separately illuminated by the electroluminescent display 500 Front and back exit, but toward the optical switching unit controllable formula advancing the first image and the second image L1 L2 730 will be blocked. Therefore, the electroluminescent display 500 of the present embodiment can avoid the problem that the brightness of the front and back sides of the conventional organic electroluminescent display is different when performing double-sided display. In addition, because of the two-sided symmetrical design, when the two-sided display is displayed, the user can choose to display the same picture or different pictures, which solves the problem that the conventional organic electroluminescent display has opposite sides on both sides of the double-sided display. Therefore, by controlling the controllable optical switch unit 730, whether it is a transparent display (double-sided non-lighting) or a non-transparent display (single-sided display, double-sided display), it can be easily achieved.

The electroluminescent display 500 of the present embodiment may have different implementation modes. For the sake of simplification of description and easy comparison, in the following embodiments, the same components are denoted by the same symbols, and only for different places. Detailed. Please refer to Figure 10. Figure 10 is a schematic view showing another embodiment of the electroluminescent display of the second preferred embodiment of the present invention. As shown in FIG. 10, the electroluminescent display 500' of the present embodiment includes a first signal unit 770 and a second signal unit 780. The first signal unit 770 is electrically connected to the first display device 530 for providing a driving signal. The first display device 530 is electrically connected to the second display device 630 for providing a driving signal to the second display device 630.

As can be seen from the above, the electroluminescent display of the second preferred embodiment places the first illuminating element 524 above the light transmitting region 506, does not overlap the first thin film transistor 508, and the second illuminating element 624 is placed. Above the light transmitting region 606, it does not overlap with the second thin film transistor 608. The conductive layer (anode) 514, 614 uses a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO) or a combination thereof, but not limited thereto, the electrode layer (cathode) 522, 622 A thinner metal material such as aluminum (Al), silver (Ag) or a combination thereof is used, but not limited thereto. In other words, in the present embodiment, the conductive layers (anodes) 514, 614 comprise transparent conductive layers, the electrode layers (cathodes) 522, 622 comprise transparent electrode layers, and the anode and cathode systems have light transmitting properties, in which case the first display device 530 and the second The display device 630 does not provide an image, and adjusts the adjustable light switch unit 730 to a light transmitting state to display a transparent display (double-sided non-lighting). If the transparent display is not required, the tunable optical switch unit 730 is adjusted to be opaque, which avoids the problem of different brightness of the front and back sides of the conventional organic electroluminescent display when performing double-sided display. In addition, because of the two-sided symmetrical design, when the two-sided display is displayed, the user can choose to display the same picture or different pictures, which solves the problem that the conventional organic electroluminescent display has opposite sides on both sides of the double-sided display. Therefore, by controlling the controllable optical switch unit 730, whether it is a transparent display (double-sided non-lighting) or a non-transparent display (single-sided display, double-sided display), it can be easily achieved.

In summary, the electroluminescent display of the present invention is a two-sided symmetrical design. When the two-sided display is displayed, the user can select the same picture or a different picture to solve the conventional organic electroluminescent display. The opposite of the image on both sides of the display. In addition, in the electroluminescent display of the present invention, the adjustment of the relative position of the internal components and the selection of materials, or the adjustment of the tunable optical switch unit to the opaque state can be avoided, and the conventional organic electroluminescent display can be prevented from being performed. The brightness of the front and back sides of the double-sided display is different. At the same time, by controlling the tunable optical switch unit, whether it is transparent display or non-transparent display, it can be easily achieved.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

100. . . Organic electroluminescent display

102. . . Lower substrate

108. . . Thin film transistor

110. . . First protective layer

114. . . anode

116. . . Second protective layer

120. . . Luminous layer

122. . . cathode

124. . . Organic light-emitting diode

126. . . Upper substrate

128. . . Plastic closures

200. . . Electroluminescent display

200’. . . Electroluminescent display

202. . . Lower substrate

204. . . Drive component area

206. . . Light transmission area

208. . . First thin film transistor

210. . . First protective layer

212. . . Opening

214. . . Conductive layer

216. . . Second protective layer

218. . . Opening

220. . . Luminous layer

222. . . Electrode layer

224. . . First illuminating element

226. . . Upper substrate

228. . . Plastic closures

230. . . First display device

302. . . Lower substrate

304. . . Drive component area

306. . . Light transmission area

308. . . Second thin film transistor

310. . . First protective layer

312. . . Opening

314. . . Conductive layer

316. . . Second protective layer

318. . . Opening

320. . . Luminous layer

322. . . Electrode layer

324. . . Second illuminating element

326. . . Upper substrate

328. . . Plastic closures

330. . . Second display device

428. . . Plastic closures

430. . . Adjustable optical switch unit

440. . . Liquid crystal layer

450. . . control unit

460. . . Signal unit

470. . . First signal unit

480. . . Second signal unit

500. . . Electroluminescent display

500’. . . Electroluminescent display

502. . . Lower substrate

504. . . Drive component area

506. . . Light transmission area

508. . . First thin film transistor

510. . . First protective layer

512. . . Opening

514. . . Conductive layer

516. . . Second protective layer

518. . . Opening

520. . . Luminous layer

522. . . Electrode layer

524. . . First illuminating element

526. . . Upper substrate

528. . . Plastic closures

530. . . First display device

602. . . Lower substrate

604. . . Drive component area

606. . . Light transmission area

608. . . Second thin film transistor

610. . . First protective layer

612. . . Opening

614. . . Conductive layer

616. . . Second protective layer

618. . . Opening

620. . . Luminous layer

622. . . Electrode layer

624. . . Second illuminating element

626. . . Upper substrate

628. . . Plastic closures

630. . . Second display device

728. . . Plastic closures

730. . . Adjustable optical switch unit

740. . . Liquid crystal layer

750. . . control unit

760. . . Signal unit

770. . . First signal unit

780. . . Second signal unit

L1. . . First image

L2. . . Second image

410. . . First polarizer

420. . . Second polarizer

431. . . First electrode

432. . . Second electrode

710. . . First polarizer

720. . . Second polarizer

731. . . First electrode

732. . . Second electrode

Figure 1 is a schematic diagram of a pixel region of a conventional organic electroluminescent display.

FIG. 2A is a schematic diagram of an image presented on the front side of a conventional organic electroluminescent display when performing double-sided transparent display.

FIG. 2B is a schematic diagram of an image presented on the reverse side of a conventional organic electroluminescent display when performing double-sided transparent display.

3 is a schematic view of a first display device of an electroluminescent display according to a first preferred embodiment of the present invention.

4 is a schematic view of a second display device of an electroluminescent display according to a first preferred embodiment of the present invention.

Figure 5 is a schematic view of an electroluminescent display of the first preferred embodiment of the present invention.

6A to 6F are schematic views of the electroluminescent display of the first preferred embodiment of the present invention in different display states.

Figure 7 is a schematic view showing another embodiment of the electroluminescent display of the first preferred embodiment of the present invention.

Figure 8 is a schematic view of an electroluminescent display of a second preferred embodiment of the present invention.

9A to 9C are schematic views showing the electroluminescent display of the second preferred embodiment of the present invention in different display states.

Figure 10 is a schematic view showing another embodiment of the electroluminescent display of the second preferred embodiment of the present invention.

200. . . Electroluminescent display

202. . . Lower substrate

204. . . Drive component area

206. . . Light transmission area

208. . . First thin film transistor

210. . . First protective layer

212. . . Opening

214. . . Conductive layer

216. . . Second protective layer

218. . . Opening

220. . . Luminous layer

222. . . Electrode layer

224. . . First illuminating element

226. . . Upper substrate

228. . . Plastic closures

230. . . First display device

302. . . Lower substrate

304. . . Drive component area

306. . . Light transmission area

308. . . Second thin film transistor

310. . . First protective layer

312. . . Opening

314. . . Conductive layer

316. . . Second protective layer

318. . . Opening

320. . . Luminous layer

322. . . Electrode layer

324. . . Second illuminating element

326. . . Upper substrate

328. . . Plastic closures

330. . . Second display device

428. . . Plastic closures

410. . . First polarizer

420. . . Second polarizer

430. . . Adjustable optical switch unit

431. . . First electrode

432. . . Second electrode

440. . . Liquid crystal layer

450. . . control unit

460. . . Signal unit

Claims (18)

An electroluminescent display comprising: a first display device comprising a first light emitting element and a first thin film transistor, wherein the first light emitting element and the first thin film transistor do not overlap; a second display device, a second light emitting element and a second thin film transistor, wherein the second light emitting element and the second thin film transistor do not overlap; and a controllable optical switch unit disposed on the first display device and the second Between the display devices; wherein the controllable optical switch unit has a light transmitting state and an opaque state. The electroluminescent display of claim 1, further comprising a control unit, and the control unit is electrically connected to the regulatable optical switch unit. The electroluminescent display device of claim 1, wherein the tunable optical switch unit comprises a liquid crystal device, and the liquid crystal device comprises a first electrode, a second electrode, and the first electrode and the second electrode One of the liquid crystal layers. The electroluminescent display of claim 3, further comprising a first polarizer and a second polarizer, wherein the first electrode is disposed between the liquid crystal layer and the first polarizer, and the second The electrode system is disposed between the liquid crystal layer and the second polarizer. The electroluminescent display of claim 1, wherein the first illuminating element comprises a first organic illuminating diode, and the first organic illuminating diode comprises a conductive layer, A light emitting layer and an electrode layer. The electroluminescent display of claim 5, wherein the conductive layer comprises a transparent conductive layer, and the electrode layer comprises a transparent electrode layer. The electroluminescent display of claim 1, wherein the second illuminating element comprises a second organic light emitting diode, and the second organic light emitting diode comprises a conductive layer, a luminescent layer and an electrode layer. The electroluminescent display of claim 7, wherein the conductive layer comprises a transparent conductive layer, and the electrode layer comprises a transparent electrode layer. The electroluminescent display of claim 1 further includes a signal unit, and the signal unit is electrically connected to the first display device and the second display device. The electroluminescent display of claim 1, further comprising a first signal unit and a second signal unit, wherein the first signal unit is electrically connected to the first display device, and the second signal unit is electrically connected To the second display device. An electroluminescent display comprising: a first display device comprising a first light emitting element and a first thin film transistor, wherein the first light emitting element overlaps the first thin film transistor, the first light emitting element comprising a first organic light emitting diode, the first organic light emitting diode The pole body comprises a conductive layer, a light emitting layer and an electrode layer, the conductive layer comprises a reflective conductive layer, and the electrode layer comprises a transparent electrode layer; a second display device comprises a second light emitting component and a second a thin film transistor, wherein the second light emitting element overlaps the second thin film transistor; and a controllable optical switch unit disposed between the first display device and the second display device; wherein the adjustable The optical switch unit has a light transmitting state and an opaque state. The electroluminescent display of claim 11, further comprising a control unit, and the control unit is electrically connected to the regulatable optical switch unit. The electroluminescent display of claim 11, wherein the tunable optical switch unit comprises a liquid crystal device, and the liquid crystal device comprises a first electrode, a second electrode, and the first electrode and the second electrode One of the liquid crystal layers. The electroluminescent display of claim 13, further comprising a first polarizer and a second polarizer, wherein the first electrode is disposed between the liquid crystal layer and the first polarizer, and the second The electrode system is disposed between the liquid crystal layer and the second polarizer. The electroluminescent display of claim 11, wherein the second illuminating element comprises a second organic illuminating diode, and the second OLED comprises a conductive layer, a luminescent layer and an electrode layer. The electroluminescent display of claim 15 wherein the conductive layer comprises a reflective conductive layer and the electrode layer comprises a transparent electrode layer. The electroluminescent display of claim 11, further comprising a signal unit, and the signal unit is electrically connected to the first display device and the second display device. The electroluminescent display of claim 11, further comprising a first signal unit and a second signal unit, wherein the first signal unit is electrically connected to the first display device, and the second signal unit is electrically connected To the second display device.