TWI382266B - Bi-stable display device - Google Patents

Description

Bistable display device

The present invention relates to a display device, and more particularly to a bistable display device for improving readability.

With the advancement of display technology, the more mature LCD display has been widely used in a variety of consumer electronic products, such as mobile phones, notebook computers, digital cameras, satellite navigation and so on. However, under the trend of thinning, low power consumption and long life, the technology of electronic paper (E-Paper) has also been born.

The E-Ink electrophoretic display includes a frontplane laminate (FPL) and a thin film transistor array substrate (TFT Array Substrate) as described by E-Ink's Electrophoretic Display (EPD) technology. The front panel includes a transparent electrode and a display layer, wherein the display layer further comprises a plurality of microcapsules and charged particles (black and white) located within the microcapsules. Therefore, by changing the electric field between the pixel electrode of the thin film transistor array substrate and the transparent electrode of the front plate, the charged particles are controlled to move within the microcapsule, and a black and white display having gray scale is presented. Due to the bistable nature of the electrophoretic display, it consumes power only in the transition state, and the advantages of flexibility and portability make the electrophoretic display more commercial.

The existing electrophoretic displays are mostly designed to be reflective, and the ambient light is used as a light source of the display to achieve the display effect. However, when the surrounding ambient light source is weak or in a dark environment, the display effect of the display will be limited, so there is a semi-transparent type with a backlight module. (transflective) The structure of the design to overcome the problem of insufficient ambient light. The penetrating mode in a semi-transmissive electrophoretic display only treats the electrophoretic display medium as a light valve, thus reducing backlight efficiency due to light scattering particles generated in the microcapsules. However, although the backlight module can be used to obtain a better display effect than the reflective type, the loss of the flexural characteristics and the loss of a large amount of energy due to the design of the backlight module are not applicable to various portable types. On the product.

Therefore, how to integrate the light source capable of improving the readability on the structure of the reflective electrophoretic display without affecting the flexibility and the display effect is the object of the present invention.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a bistable display device that provides an auxiliary light source by means of a front light source to improve the readability of the display.

Another object of the present invention is to provide a bistable display device. By integrating a photo sensor, the front light source can adjust the intensity of the light source according to the intensity of the ambient light to provide a stable display image and save unnecessary energy. loss.

A bistable display device according to an embodiment of the invention includes a first substrate, a thin film transistor array, and a bi-stable display panel. The thin film transistor array is disposed on the first substrate and includes a plurality of pixel electrodes. The bistable display panel is disposed on the thin film transistor array, and includes a second substrate, a plurality of closed sections, a display medium, a common electrode, and a plurality of front light sources, wherein the display medium is placed in the closed section, the common electrode and the first Two substrates are disposed on the closed sections, and the front light source is integrated in the second a substrate and a common electrode.

According to an embodiment of the bistable display device of the present invention, the front light source is an Organic Light Emitting Diode (OLED), and the structure thereof comprises a cathode layer, an electron transport layer, a light emitting layer, a hole transport layer and an anode. The layer wherein the cathode layer is aluminum metal (Al) and the anode layer is indium tin oxide (ITO). Since the common electrode of the bistable display panel is also indium tin oxide, the anode layer and the common electrode can form individual patterns on the same plane in the same process, and the front light source is integrated into the bistable display panel by using this method. The second substrate and the common electrode. In addition, the bistable display device of the present invention further includes a photo sensor disposed in the second substrate, and is connected to the front light source by a feedback control element, and adjusts the luminous intensity of the front light source according to the ambient light intensity.

Therefore, the bistable display device of the present invention utilizes characteristics such as thinness, flexibility, and surface luminescence of the organic electroluminescent element, and forms a pixel electrode of the thin film transistor array and the organic electroluminescent element by forming the same on the same plane. The anode layer integrates the front light source into the bistable display panel and the second substrate, thereby improving the problem that the existing electrophoretic display has low readability when the ambient light is insufficient. In addition, the bistable display device of the present invention can be further matched with a light sensor to adjust the luminous intensity of the front light source according to the intensity of the ambient light, so that the user can provide the appropriate light source by the front light source under different ambient light conditions. Brightness, a stable display, and unnecessary energy loss.

Please refer to Figure 1 and Figure 2. 1 is a schematic structural view of a bistable display device according to a first embodiment of the present invention; Another embodiment of the medium 330 is shown in FIG.

The bistable display device of the first embodiment of the present invention includes a first substrate 100, a thin film transistor array 200, and a bi-stable display panel 300. The thin film transistor array 200 is disposed on the first substrate 100 and includes a plurality of pixel electrodes 210. The bistable display panel 300 is disposed on the thin film transistor array 200 and includes a second substrate 310, a plurality of closed sections 320, a display medium 330, a common electrode 340, and a plurality of front light sources 350. The common electrode 340 and the second substrate 310 are disposed on the closed sections 320 , and the front light source 350 is integrated into the second substrate 310 and the common electrode 340 .

In the present embodiment, the closed section 320 is defined by a plurality of microcups, but is not intended to limit the scope of the present invention, and may be defined by a plurality of microcapsules or a plurality of partition walls. Each microcup 320 includes a side wall 325, and a plurality of front light sources 350 are respectively disposed corresponding to the side walls 325. The second substrate 310 is disposed on the common electrode 340.

In the first embodiment of the present invention, the display medium 330 is a plurality of charged dye particles, including negatively charged black particles 331 and positively charged white particles 332, and the pixel electrodes 210 of the thin film transistor array 200 are The electric field of the common electrode 340 of the bistable display panel 300 is changed to control the black particles 331 and the white particles 332 to move within the microcup 320, presenting a black and white display with gray scale. Although the display medium 330 of the embodiment of the present invention is disclosed by two charged dye particles, the scope of the present invention should not be limited. The display medium 330 may also be a dielectric black fluid 333 and a plurality of positively charged white particles. Another embodiment of 334 (as shown in Figure 2), because the rest of the structure The same as the embodiment of Fig. 1, which will not be repeated here.

Please refer to FIG. 1 , FIG. 3A , FIG. 3B , and FIG. 4 . FIG. 3A is a schematic diagram showing the configuration of the light source 350 on the bistable display panel 300 before the embodiment of the present invention; FIG. 3B is another configuration of the light source 350 on the bistable display panel 300 before the embodiment of the present invention. FIG. 4 is a schematic structural view of a front light source 350 in an embodiment of the present invention.

In the first embodiment of the present invention, the front light source 350 is an Organic Light Emitting Diode (OLED), and the structure thereof comprises a cathode layer 351, an electron transport layer 352, a light emitting layer 353, and a hole. The transport layer 354 and an anode layer 355, wherein the cathode layer 351 is aluminum metal (Al), and the anode layer 355 is indium tin oxide (ITO). Since the common electrode 340 of the bistable display panel 300 is also indium tin oxide, the anode layer 355 and the common electrode 340 can form individual patterns on the same plane in the same process, and the front light source is integrated by this method. 350 is within the second substrate 310 of the bistable display panel 300 and the common electrode 340.

In addition, in the configuration of the front light source 350, since the front light source 350 is respectively disposed corresponding to the sidewall 325 of the microcup 320, wherein the anode layer 355 and the common electrode 340 can be integrated in the same plane, the condition of the product and the uniform distribution of the front light source can be visually recognized. The front light source 350 is designed as a point light source arranged in a spaced relationship or a surface light source arranged in a strip shape (as shown in FIGS. 3A and 3B).

Referring to FIG. 5, it is a schematic structural view of a bistable display device according to a second embodiment of the present invention. Since the light source 350 is configured before the bistable display device of the first embodiment, even after the brightness is uniformized, It can cause visual discomfort to the user due to the outwardly diverging light source. In addition, the bistable display device of the embodiment of the invention is a reflective bistable display device, so that the strong ambient light can provide sufficient display light source, but the surface of the cathode layer is a metal layer, which causes light reflection. The situation may cause visual discomfort to the user. Therefore, the bistable display device of the second embodiment further includes a light shield 356 and an anti reflection 400 in comparison with the bistable display device of the first embodiment, wherein the light shielding layer 356 The anti-reflection layer 400 is disposed on the second substrate 310. Thereby, the visual sensation caused by the front light source 350 and the ambient light can be significantly improved.

Please refer to FIG. 6, which is a schematic structural view of a bistable display device according to a third embodiment of the present invention. The bistable display device of the third embodiment of the present invention is based on the structure of the bistable display device of the first embodiment or the second embodiment, and a photo sensor 500 is added to the second substrate 310. The light source intensity of the front light source 350 is adjusted according to the ambient light intensity by using a feedback control element connected to the plurality of front light sources 350.

As can be seen from the above, the bistable display device of the present invention has the following effects and advantages:

The bistable display device of the present invention utilizes characteristics such as thinness, flexibility, and surface luminescence of the organic electroluminescent element, and forms the common electrode 340 of the bistable display panel 300 and the organic electroluminescent element by forming the same plane. The anode layer 345 integrates the front light source 350 into the second substrate 310 of the bistable display panel 300 and the common electrode 340, thereby improving the problem that the existing electrophoretic display has low readability when the ambient light is insufficient. In addition, the bistable display device of the present invention can be further matched with the light sensor 500. The illumination intensity of the front light source 350 is adjusted according to the intensity of the ambient light, so that the user can obtain a stable display image by using the appropriate brightness provided by the front light source under different ambient light conditions, and save unnecessary energy loss.

The present invention has been disclosed in the above embodiments, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application attached.

100‧‧‧First substrate

200‧‧‧film transistor array

210‧‧‧ pixel electrodes

300‧‧‧Bistable display panel

310‧‧‧second substrate

320‧‧‧closed interval

325‧‧‧ side wall

330‧‧‧Display media

331‧‧‧Black particles

332‧‧‧White particles

333‧‧‧Black fluid

334‧‧‧White particles

340‧‧‧Common electrode

350‧‧‧ Front light source

351‧‧‧ cathode layer

352‧‧‧Electronic transport layer

353‧‧‧Lighting layer

354‧‧‧ hole transport layer

355‧‧‧anode layer

356‧‧‧Lighting layer

400‧‧‧Anti-reflective layer

500‧‧‧Photosensor

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood.

Fig. 1 is a schematic view showing the structure of a bistable display device according to a first embodiment of the present invention.

Fig. 2 is a view showing another embodiment of the medium shown in Fig. 1.

3A is a schematic view showing the arrangement of a light source on a bistable display panel before the embodiment of the present invention.

FIG. 3B is a schematic diagram showing another configuration of the light source on the bistable display panel before the embodiment of the present invention.

Figure 4 is a schematic view showing the structure of a front light source in the embodiment of the present invention.

Figure 5 is a schematic view showing the structure of a bistable display device according to a second embodiment of the present invention.

Figure 6 is a block diagram showing the structure of a bistable display device according to a third embodiment of the present invention.

100‧‧‧First substrate

200‧‧‧film transistor array

210‧‧‧ pixel electrodes

300‧‧‧Bistable display panel

310‧‧‧second substrate

320‧‧‧closed interval

325‧‧‧ side wall

330‧‧‧Display media

331‧‧‧Black particles

332‧‧‧White particles

340‧‧‧Common electrode

350‧‧‧ Front light source

Claims (14)

A bistable display device comprising: a first substrate; a thin film transistor array disposed on the first substrate and comprising a plurality of pixel electrodes; and a bistable display panel disposed on the thin film transistor array And comprising a second substrate, a plurality of closed sections, a display medium, a common electrode, and a plurality of front light sources, wherein the display medium is disposed in the closed sections, and the common electrode and the second substrate are disposed on In the closed sections, each of the front light sources is an organic electroluminescent element, and the organic electroluminescent element comprises an anode layer, and the anode layer and the common electrode are formed into individual patterns by the same material, so that The front light sources are integrated on the second substrate and the common electrode. The bistable display device of claim 1, wherein the closed intervals are defined by a plurality of microcapsules, a plurality of microcups or a plurality of dividing walls. The bistable display device of claim 2, wherein each of the closed sections comprises a side wall, and the front light sources respectively correspond to the side wall configurations. The bistable display device of claim 3, wherein the structure of each of the organic electroluminescent elements along the second substrate toward the bistable display panel is a cathode layer and an electron transport layer. a light emitting layer, a hole transport layer and the anode layer. The bistable display device according to claim 4, wherein The cathode layer is a metal and the anode layer is indium tin oxide. The bistable display device of claim 5, wherein the common electrode of the bistable display panel is indium tin oxide, and the anode layers of the organic electroluminescent elements are located same plane. The bistable display device of claim 6, wherein the front light sources are point sources in spaced configurations. The bistable display device of claim 6, wherein the front light sources are surface light sources in a strip configuration. The bistable display device of claim 7 or 8, wherein each of the front light sources further comprises a light shielding layer disposed on the cathode layer. The bistable display device of claim 1, further comprising an anti-reflection layer disposed on the second substrate. The bistable display device of claim 1, further comprising a photo sensor disposed in the second substrate. The bistable display device of claim 1, wherein the display medium is a plurality of charged dye particles. The bistable display device of claim 12, wherein the dye particles comprise negatively charged black particles and positively charged white particles. The bistable display device of claim 1, wherein the display medium is a dielectric black fluid and a plurality of positively charged white particles.