Patent Publication Number: US-2020286966-A1

Title: Transparent display panel and displaying method of same

Description:
FIELD OF INVENTION 
     The present disclosure relates to display technologies, and more particularly, to a transparent display panel and a displaying method of the same. 
     BACKGROUND OF INVENTION 
     Transparent displays are favored by people for their high transparency and unique display application effects, and are often displayed as window displays or head-up displays. However, due to low contrast, transparent displays often result in poor viewing performance, especially when ambient is brighter, which has a great influence on a display image. If a liquid crystal display (LCD) is used as a transparent display panel, aperture ratio of a backlight module of the LCD, a color resistance (CF), and a polarizer, and liquid crystal efficiency may cause transmittance of the transparent display to be lower, and then the light utilization rate is lower. At present, transparent display technology is gradually shifting from LCD displays to organic light emitting displays (OLEDs). However, the OLED display technology has lower brightness and higher reflectivity due to device material limitations, resulting in lower contrast. 
     Therefore, there is a need to solve the above problems. 
     SUMMARY OF INVENTION 
     In view of the above, the present disclosure provides a transparent display panel and a displaying method of the same to resolve above-mentioned technical problem. 
     In order to achieve above-mentioned object of the present disclosure, one embodiment of the disclosure provides a transparent display panel including an organic light emitting module and a polymer dispersed liquid crystal module. The polymer dispersed liquid crystal module includes a lower substrate and a display surface. The organic light emitting module is disposed on another side of the lower substrate. The organic light emitting module comprises a display surface. The display surface of the organic light emitting module faces an opposite direction of the display surface of the polymer dispersed liquid crystal module. 
     In one embodiment of the disclosure, the polymer dispersed liquid crystal module includes a lower electrode layer disposed on a lower surface of the lower substrate, a polymer dispersed liquid crystal material disposed under the lower electrode layer, and an upper electrode layer disposed under the polymer dispersed liquid crystal material. 
     In one embodiment of the disclosure, the polymer dispersed liquid crystal module further includes an upper substrate disposed under the upper electrode layer and a polarizer sheet disposed under the upper substrate. A thickness of the polymer dispersed liquid crystal material is one fourth of a wavelength of incident light. 
     In one embodiment of the disclosure, the organic light emitting module and the polymer dispersed liquid crystal module share the lower substrate. The organic light emitting module includes a thin film transistor layer disposed on the lower substrate, an anode layer disposed on the thin film transistor layer, a hole transporting layer disposed on the anode layer, a light emitting layer disposed on the hole transporting layer, an electron transporting layer disposed on the light emitting layer, and a cathode layer disposed on the electron transporting layer. 
     In one embodiment of the disclosure, the transparent display panel further includes a cover plate disposed on the cathode layer. 
     In one embodiment of the disclosure, the organic light emitting module includes a thin film transistor layer disposed on the lower substrate, an anode layer disposed on the thin film transistor layer, a hole transporting layer disposed on the anode layer, a light emitting layer disposed on the hole transporting layer, an electron transporting layer disposed on the light emitting layer, and a cathode layer disposed on the electron transporting layer. 
     In one embodiment of the disclosure, the transparent display panel further includes a cover plate disposed on the cathode layer. 
     Furthermore, another embodiment of the disclosure provides a displaying method of a transparent display panel. The transparent display panel includes an organic light emitting module and a polymer dispersed liquid crystal module. The polymer dispersed liquid crystal module includes a lower substrate and a display surface. The organic light emitting module is disposed on another side of the lower substrate. The organic light emitting module includes a display surface. The display surface of the organic light emitting module faces an opposite direction of the display surface of the polymer dispersed liquid crystal module. The displaying method includes steps of: 
     the organic light emitting module turning on or turning off corresponding pixels according to an image signal; 
     the polymer dispersed liquid crystal module driving the polymer dispersed liquid crystal corresponding to the pixels turning on by the organic light emitting module as a scattering state; and 
     the polymer dispersed liquid crystal module driving the polymer dispersed liquid crystal corresponding to the pixels turning off by the organic light emitting module as a transparent state. 
     In one embodiment of the disclosure, the organic light emitting module is turned off and the polymer dispersed liquid crystal module is turned on to display when ambient light is greater than a predetermined luminance. 
     In one embodiment of the disclosure, the organic light emitting module and the polymer dispersed liquid crystal module are both turned on to undergo a transparent display when ambient light is lower than a predetermined luminance. 
     In comparison with prior art, the disclosure of the transparent display panel and the displaying method of the transparent display include the organic light emitting module disposed on another side of the lower substrate. The display surface of the organic light emitting module faces an opposite direction of the display surface of the polymer dispersed liquid crystal module. The polymer dispersed liquid crystal module driving the polymer dispersed liquid crystal corresponding to the pixels turning on by the organic light emitting module as a scattering state. The polymer dispersed liquid crystal module driving the polymer dispersed liquid crystal corresponding to the pixels turning off by the organic light emitting module as a transparent state. So that an embodiment of the transparent display panel of the disclosure behaves as a reflective display under strong ambient light to reduce power consumption and behave as a transparent display when ambient is darker and modulate ambient light by polymer dispersed liquid crystal to enhance contrast. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is schematic view of a structure of a transparent display panel according to an embodiment of the present disclosure. 
         FIG. 2  is a schematic view of a structure of a transparent display panel according to another embodiment of the present disclosure. 
         FIG. 3  is a schematic applying view of a transparent display panel according to an embodiment of the present disclosure. 
         FIG. 4  is another schematic applying view of a transparent display panel according to an embodiment of the present disclosure. 
         FIG. 5  is a schematic flowchart of a displaying method of the transparent display panel according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The following description of the embodiments is provided by reference to the following drawings and illustrates the specific embodiments of the present disclosure. Directional terms mentioned in the present disclosure, such as “up,” “down,” “top,” “bottom,” “forward,” “backward,” “left,” “right,” “inside,” “outside,” “side,” “peripheral,” “central,” “horizontal,” “peripheral,” “vertical,” “longitudinal,” “axial,” “radial,” “uppermost” or “lowermost,” etc., are merely indicated the direction of the drawings. Therefore, the directional terms are used for illustrating and understanding of the application rather than limiting thereof. 
     Referring to  FIG. 1 , one embodiment of the disclosure provides a transparent display panel  1000  including an organic light emitting module  100  and a polymer dispersed liquid crystal (PDLC) module  200 . The polymer dispersed liquid crystal module  200  includes a lower substrate  21  and a display surface  20 . The organic light emitting module  100  is disposed on another side of the lower substrate  21 . The organic light emitting module  100  comprises a display surface  10 . The display surface  10  of the organic light emitting module  100  faces an opposite direction of the display surface  20  of the polymer dispersed liquid crystal module  200 . 
     In one embodiment of the disclosure, the polymer dispersed liquid crystal module  200  includes a lower electrode layer  22  disposed on a lower surface of the lower substrate  21 , a polymer dispersed liquid crystal material  23  disposed under the lower electrode layer  22 , and an upper electrode layer  24  disposed under the polymer dispersed liquid crystal material  23 . 
     In detail, taking a polymer dispersed liquid crystal material of positive dielectric heterogeneity as an example, when there is no external electric field, the liquid crystal materials are irregularly arranged, thereby causing scattering of incident light. When an electric field is applied, the liquid crystal material is regularly arranged, thereby causing partial reflection and partial transmission of the incident light. Therefore, the image can be observed regardless of which side of the double-sided display  200 . 
     In detail, a thickness of the polymer dispersed liquid crystal material  23  is one fourth of a wavelength λ of incident light. The wavelength λ of the incident light is within range of wavelengths of visible light or is a mean of wavelengths of visible light, the disclosure is not limit thereto. 
     In detail, the polymer dispersed liquid crystal module  100  further includes a thin film transistor layer (not show) disposed under the lower substrate  21 . 
     In detail, the lower electrode layer  22  and the upper electrode layer  24  are configured for controlling twisting of the polymer dispersed liquid crystal. 
     One embodiment of the disclosure, the polymer dispersed liquid crystal module  200  further includes an upper substrate  25  disposed under the upper electrode layer  24  and a polarizer sheet  26  disposed under the upper substrate  25 . 
     In detail, the transparent display panel  1000  may further include an anti-reflection film, which may be a multilayer film structure or a single layer film having a film thickness equal to ¼ of a wavelength λ of incident light. 
     In one embodiment of the disclosure, the organic light emitting module  100  and the polymer dispersed liquid crystal module  200  share the lower substrate  21 . The organic light emitting module  100  includes a thin film transistor layer  11  disposed on the lower substrate  21 , an anode layer  12  disposed on the thin film transistor layer  11 , a hole transporting layer  13  disposed on the anode layer  12 , a light emitting layer  14  disposed on the hole transporting layer  13 , an electron transporting layer  15  disposed on the light emitting layer  14 , and a cathode layer  16  disposed on the electron transporting layer  15 . 
     In detail, the anode layer  12 , the hole transporting layer  13 , the light emitting layer  14 , the electron transporting layer  15 , and the cathode layer  16  constitute an organic light emitting pixel  101  of the organic light emitting module  100 . 
     In detail, the cathode layer  16  includes transparent electrode material. 
     In detail, the transparent electrode material is indium tin oxide. 
     In detail, the lower substrate  21  is transparent substrate. The anode layer  12  of the organic light emitting module  100  includes metallic electrode material to enhance reflection of light beams incident the polymer dispersed liquid crystal module  200 . 
     In detail, because the metal electrode occupies a small area of the transparent display panel  1000 , the reflection effect of the metal electrode does not affect the effect of the transparent display. 
     In one embodiment of the disclosure, the transparent display panel  1000  further includes a cover plate  17  disposed on the cathode layer  16 . 
     Referring to  FIG. 2 , in one embodiment of the disclosure, the organic light emitting module  100 ′ includes a thin film transistor substrate  11 ′ disposed on the lower substrate  21 , a thin film transistor layer  11  disposed on the thin film transistor substrate  11 ′, an anode layer  12  disposed on the thin film transistor layer  11 , a hole transporting layer  13  disposed on the anode layer  12 , a light emitting layer  14  disposed on the hole transporting layer  13 , an electron transporting layer  15  disposed on the light emitting layer  14 , and a cathode layer  16  disposed on the electron transporting layer  15 . 
     In detail, the anode layer  12 , the hole transporting layer  13 , the light emitting layer  14 , the electron transporting layer  15 , and the cathode layer  16  constitute an organic light emitting pixel  101  of the organic light emitting module  100 ′. 
     In detail, the cathode layer  16  includes transparent electrode material. 
     In detail, the transparent electrode material is indium tin oxide. 
     In detail, the lower substrate  21  is transparent substrate. The anode layer  12  of the organic light emitting module  100 ′ includes metallic electrode material to enhance reflection of light beams incident the polymer dispersed liquid crystal module  200 . 
     In detail, because the metal electrode occupies a small area of the transparent display panel  1000 ′, the reflection effect of the metal electrode does not affect the effect of the transparent display. 
     In one embodiment of the disclosure, the transparent display panel  1000 ′ further includes a cover plate  17  disposed on the cathode layer  16 . 
     Referring to  FIGS. 1, 3, and 5 , furthermore, another embodiment of the disclosure provides a displaying method of a transparent display panel. The transparent display panel  1000 ″ includes an organic light emitting module  100 ″ and a polymer dispersed liquid crystal module  200 ″. The polymer dispersed liquid crystal module  200 ″ includes a lower substrate  21  and a display surface  20 . The organic light emitting module  100 ″ is disposed on another side of the lower substrate  21 . The organic light emitting module  100 ″ includes a display surface  10 . The display surface  10  of the organic light emitting module  100 ″ faces an opposite direction of the display surface  20  of the polymer dispersed liquid crystal module  200 ″. The displaying method includes steps of: 
     Block S 1 : the organic light emitting module  100 ″ turning on or turning off corresponding pixels according to an image signal P 1 , P 2 , . . . ; 
     Block S 2 : the polymer dispersed liquid crystal module  200 ″ driving the polymer dispersed liquid crystal  23  corresponding to the pixels P 1  turning on by the organic light emitting module  100 ″ as a scattering state; and 
     Block S 3 : the polymer dispersed liquid crystal module  200 ″ driving the polymer dispersed liquid crystal  23  corresponding to the pixels P 2  turning off by the organic light emitting module  100 ″ as a transparent state. 
     In detail, each pixel P 1 , P 2 , . . . of the organic light emitting module  100 ″ includes, for example, three sub-pixels such as red sub-pixel R, green sub-pixel G, and blue sub-pixel B, but the disclosure is not limit thereto. 
     In detail, a resolution of the organic light emitting module  100 ″ is the same as a resolution of the polymer dispersed liquid crystal module  200 ″, and positions of pixel electrodes of the two modules are in one-to-one correspondence. However, the disclosure is not limited thereto. The resolution of the organic light emitting module  100 ″ may be proportional to the resolution of the polymer dispersed liquid crystal module  200 ″, and the positions of the pixel electrodes of two modules are generally corresponding to each other or having a corresponding relationship. 
     In detail, in order to clearly express light directions in application of the disclosure, some parts of the transparent display panel  1000 ″ in  FIG. 3  are not shown. Only the lower substrate  21 , the pixels P 1 , P 2 , the cover plate  17 , the polymer dispersed liquid crystal material  23 , the upper substrate  25  and the polarizer sheet  26  are shown in the figure. 
     Referring to  FIG. 4 , in one embodiment of the disclosure, the organic light emitting module  100 ″ is turned off and the polymer dispersed liquid crystal module  200 ″ is turned on to display when ambient light is greater than a predetermined luminance. 
     In detail, in order to clearly express light directions in application of the disclosure, some parts of the transparent display panel  1000 ″ in  FIG. 4  are not shown. Only the lower substrate  21 , the pixels P 1 , P 2 , the cover plate  17 , the polymer dispersed liquid crystal material  23 , the upper substrate  25  and the polarizer sheet  26  are shown in the figure. 
     Referring to  FIG. 3 , in one embodiment of the disclosure, the organic light emitting module  100 ″ and the polymer dispersed liquid crystal module  200 ″ are both turned on to undergo a transparent display when ambient light is lower than a predetermined luminance. 
     In detail, the transparent display panel  1000 ″ can adjust according to the intensity of the background light to improve contrast of display of the organic light emitting module  100 ″. 
     In comparison with prior art, the disclosure of the transparent display panel and the displaying method of the transparent display include the organic light emitting module disposed on another side of the lower substrate. The display surface of the organic light emitting module faces an opposite direction of the display surface of the polymer dispersed liquid crystal module. The polymer dispersed liquid crystal module driving the polymer dispersed liquid crystal corresponding to the pixels turning on by the organic light emitting module as a scattering state. The polymer dispersed liquid crystal module driving the polymer dispersed liquid crystal corresponding to the pixels turning off by the organic light emitting module as a transparent state. So that an embodiment of the transparent display panel of the disclosure behaves as a reflective display under strong ambient light to reduce power consumption and behave as a transparent display when ambient is darker and modulate ambient light by polymer dispersed liquid crystal to enhance contrast. 
     The present disclosure has been described by the above embodiments, but the embodiments are merely examples for implementing the present disclosure. It must be noted that the embodiments do not limit the scope of the invention. In contrast, modifications and equivalent arrangements are intended to be included within the scope of the invention.