Transmissive and reflective switchable display devices

Abstract

The application discloses a display device switchable between transmission and reflection, comprising an OLED display panel and a liquid crystal display panel arranged on the light emitting side of the OLED display panel; the liquid crystal display panel comprises a second substrate, a liquid crystal layer and a first substrate arranged in sequence, a linear polarizer and a quarter-wave plate are arranged on the first substrate, the quarter-wave plate is arranged on the side of the linear polarizer facing the liquid crystal layer, and the transmission axis of the linear polarizer and the fast and slow axis of the quarter-wave plate are at an angle of 45 degrees. In the transmission mode, the liquid crystal molecules in the whole liquid crystal layer are controlled to be in a standing posture, the OLED display panel is turned on and displays a picture, the light emitted by the OLED display panel can pass through the liquid crystal display panel, and the ambient light reflected by the OLED display panel is absorbed by the linear polarizer, so that the ambient light reflected by the OLED display panel is prevented from reducing the contrast of the transmission display; in the reflection mode, the OLED display panel is turned off, so that the liquid crystal display panel can display a picture by using the ambient light reflected by the OLED display panel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a display device switchable between transmission and reflection. BACKGROUND

[0002] With the development of the information age, the application of display screens is increasingly broad and diversified, and various technical display screens are also developing rapidly. Self-luminous display is the next generation of display after LCD (liquid crystal display), and has the advantages of good image quality, small size, light weight, low driving voltage, low power consumption, no radiation, and relatively low manufacturing cost. Its development and application are increasingly widespread. Self-luminous display includes OLED (Organic Light-Emitting Diode) display and Micro LED (micro light-emitting diode) display.

[0003] OLED display is driven by voltage to emit light by organic light-emitting material, which results in high power consumption of OLED display. Moreover, when natural light from the outside is irradiated onto the OLED screen, it will be reflected back by the metal cathode after penetrating through the encapsulation layer. The reflected light from the cathode will also reduce the display contrast and affect the display. SUMMARY

[0004] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present application is to provide a display device switchable between transmission and reflection, so as to solve the problems of high display power consumption and low contrast in bright environment of OLED display in the prior art.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] The present application provides a display device switchable between transmission and reflection, comprising an OLED display panel and a liquid crystal display panel arranged on the light-emitting side of the OLED display panel.

[0007] The liquid crystal display panel comprises a first substrate, a second substrate arranged opposite to the first substrate, and a liquid crystal layer between the first substrate and the second substrate. The first substrate is located on the side of the liquid crystal layer away from the OLED display panel, and the second substrate is located on the side of the liquid crystal layer facing the OLED display panel. A linear polarizer and a quarter-wave plate are arranged on the first substrate. The quarter-wave plate is located on the side of the linear polarizer facing the liquid crystal layer. The transmission axis of the linear polarizer and the fast and slow axis of the quarter-wave plate are at an angle of 45°. A control electrode is arranged on the second substrate. A common electrode is arranged on the first substrate or the second substrate and cooperates with the control electrode.

[0008] The OLED display panel comprises a substrate, an anode, a light-emitting layer and a cathode which are sequentially arranged on the substrate, and the anode and the cathode are used to control the light-emitting state of the light-emitting layer.

[0009] In the transmission mode, all the liquid crystal molecules in the liquid crystal layer are in the standing posture, the ambient light reflected by the cathode is absorbed by the linear polarizer, the OLED display panel is turned on and displays the picture, and the light emitted by the OLED display panel can pass through the liquid crystal display panel; in the reflection mode, the OLED display panel is turned off, the liquid crystal molecules in the liquid crystal layer in the dark state region are in the standing posture, the ambient light reflected by the cathode in the dark state region is absorbed by the linear polarizer, the liquid crystal molecules in the liquid crystal layer in the bright state region are in the lying posture and have a phase delay of λ / 4, and the ambient light reflected by the cathode in the bright state region can be emitted from the linear polarizer.

[0010] Further, the display device comprises a diffuse reflection structure, and the diffuse reflection structure is arranged on the light-emitting side of the OLED display panel.

[0011] Further, the diffuse reflection structure is arranged on the side of the second substrate facing the liquid crystal layer.

[0012] Alternatively, the diffuse reflection structure is arranged on the side of the second substrate away from the liquid crystal layer.

[0013] Alternatively, the diffuse reflection structure is arranged on the side of the OLED display panel facing the liquid crystal display panel.

[0014] Further, the diffuse reflection structure has a plurality of convex structures, or the diffuse reflection structure is a PDLC liquid crystal box or a PNLC liquid crystal box.

[0015] Further, a plurality of scanning lines, a plurality of data lines and a plurality of thin film transistors are arranged on the second substrate, the scanning lines and the data lines are insulated and crossed to define a plurality of first pixel units arranged in a matrix, the control electrode comprises a pixel electrode corresponding to each first pixel unit, and the pixel electrode is electrically connected to the scanning line and the data line adjacent to the thin film transistor through the thin film transistor.

[0016] Further, the display device has a pattern area and a background area, the control electrode comprises a first electrode and a second electrode which are insulated from each other, the first electrode corresponds to the pattern area, and the second electrode corresponds to the background area.

[0017] Further, the first substrate is provided with a black matrix and a color resist layer, the black matrix is used to separate the color resist layers from each other, the liquid crystal display panel has a first pixel unit corresponding to the color resist layer, the OLED display panel has a second pixel unit corresponding to the color resist layer, and the first pixel unit and the second pixel unit correspond to each other one by one.

[0018] Further, the first substrate is provided with the common electrode matched with the control electrode, the liquid crystal molecules in the liquid crystal layer are arranged parallel to the first substrate and the second substrate, the arrangement direction of the liquid crystal molecules close to the first substrate is perpendicular to the arrangement direction of the liquid crystal molecules close to the second substrate, and the liquid crystal layer has a phase delay of λ / 4 in an initial state.

[0019] Alternatively, the first substrate is provided with the common electrode matched with the control electrode, the liquid crystal molecules in the liquid crystal layer are arranged perpendicular to the first substrate and the second substrate, the long axis of the liquid crystal molecules is at an angle of 45° with the transmission axis of the linear polarizer when the liquid crystal molecules are in a lying posture, and the liquid crystal layer has a phase delay of λ / 4.

[0020] Further, the liquid crystal layer comprises liquid crystal molecules and nanoparticles mixed with each other, the refractive index of the nanoparticles is different from the refractive index of the liquid crystal molecules, the nanoparticles and the liquid crystal molecules match with each other and can reflect light and scatter light.

[0021] Further, the refractive index of the nanoparticles is different from the refractive index of the liquid crystal molecules by 0.1 or more.

[0022] And / or, the nanoparticles are in a spherical structure or a strip-shaped structure.

[0023] And / or, the diameter of the nanoparticles is 5nm-500nm.

[0024] And / or, the nanoparticles are in a white or transparent state.

[0025] The present application has the beneficial effect that: by setting the liquid crystal display panel on the light emitting side of the OLED display panel, and the liquid crystal display panel is provided with a linear polarizer and a quarter-wave plate that cooperate with each other. In the transmission mode, the liquid crystal molecules in the whole liquid crystal layer are controlled to be in the standing posture, the OLED display panel is turned on and displays the picture, so that the light emitted by the OLED display panel can pass through the liquid crystal display panel, and the ambient light reflected by the OLED display panel is absorbed by the linear polarizer, thereby avoiding the ambient light reflected by the OLED display panel to reduce the contrast of the transmission display; in the reflection mode, the OLED display panel is turned off, and the liquid crystal display panel normally displays, so that the liquid crystal display panel can use the ambient light reflected by the OLED display panel to display the picture, so as to reduce the power consumption of the display. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structure schematic diagram of the display device in the initial state in the embodiment one of the present application.

[0027] Figure 2 is a plane structure schematic diagram of the second substrate in the embodiment one of the present application.

[0028] Figure 3 is a structure schematic diagram of the display device in the bright state in the reflection mode in the embodiment one of the present application.

[0029] Figure 4 is a light path principle schematic diagram of the display device in the bright state in the reflection mode in the embodiment one of the present application.

[0030] Figure 5 is a structure schematic diagram of the display device in the dark state in the reflection mode in the embodiment one of the present application.

[0031] Figure 6 is a light path principle schematic diagram of the display device in the dark state in the reflection mode in the embodiment one of the present application.

[0032] Figure 7 is a structure schematic diagram of the display device in the bright state in the transmission mode in the embodiment one of the present application.

[0033] Figure 8 is a light path principle schematic diagram of the display device in the bright state in the transmission mode in the embodiment one of the present application.

[0034] Figure 9 is one of the structure schematic diagrams of the display device in the initial state in the embodiment two of the present application.

[0035] Figure 10 is the second structure schematic diagram of the display device in the initial state in the embodiment two of the present application.

[0036] Figure 11is a structural schematic view of the display device in the dark state in the reflective mode in Embodiment Three of the present application.

[0037] Figure 12 is a structural schematic view of the display device in the bright state in the reflective mode in Embodiment Three of the present application.

[0038] Figure 13 is a structural schematic view of the display device in the initial state in Embodiment Four of the present application.

[0039] Figure 14 is one of the planar structural schematic views of the display device in Embodiment Four of the present application.

[0040] Figure 15 is one of the planar structural schematic views of the control electrode in Embodiment Four of the present application.

[0041] Figure 16 is another planar structural schematic view of the display device in Embodiment Four of the present application.

[0042] Figure 17 is another planar structural schematic view of the control electrode in Embodiment Four of the present application.

[0043] Figure 18 is a structural schematic view of the display device in the screen-off display state in Embodiment Four of the present application.

[0044] Figure 19 is a structural schematic view of the display device in the initial state in Embodiment Five of the present application.

[0045] Figure 20 is a planar structural schematic view of the first substrate in Embodiment Five of the present application.

[0046] Figure 21 is a planar structural schematic view of the OLED display panel in Embodiment Five of the present application.

[0047] Figure 22 is a structural schematic view of the display device in the initial state in Embodiment Six of the present application.

[0048] Figure 23 is a structural schematic view of the spherical nano-particle and the liquid crystal molecule in Embodiment Six of the present application.

[0049] Figure 24 is a structural schematic view of the strip nano-particle and the liquid crystal molecule in Embodiment Six of the present application. DETAILED DESCRIPTION

[0050] In order to further clarify the technical means and effects taken by the present application to achieve the predetermined inventive purpose, the specific embodiments, structures, features and effects of the transmissive and reflective switchable display device according to the present application are described in detail below in combination with the drawings and preferred embodiments.

[0051] [Embodiment One]

[0052] Figure 1 is a structural schematic diagram of the display device in the initial state in Embodiment One of the present application. Figure 2 is a planar structural schematic diagram of the second substrate in Embodiment One of the present application.

[0053] As shown in Figure 1 and Figure 2 , Embodiment One of the present application provides a transmissive and reflective switchable display device, which includes an OLED display panel 20 and a liquid crystal display panel 10 arranged on the light-emitting side of the OLED display panel 20. The OLED display panel 20 is used to control the picture display in the transmissive mode, and the liquid crystal display panel 10 is used to control whether the light reflected by the OLED display panel 20 can be emitted out of the liquid crystal display panel 10.

[0054] The OLED display panel 20 includes a substrate 21, an anode 22, a light-emitting layer 23 and a cathode 24 arranged on the substrate 21 in sequence, and the light-emitting layer 23 is located between the anode 22 and the cathode 24. The anode 22 and the cathode 24 are used to control the light-emitting state of the light-emitting layer 23. By applying corresponding electrical signals to the anode 22 and the cathode 24, the corresponding light-emitting layer 23 is controlled to emit light. The anode 22 can include an Indium Tin Oxide (ITO) trace layer, a silver (Ag) reflection layer and an ITO electrode layer arranged on the substrate 21 in sequence. The ITO trace layer and the ITO electrode layer can also be replaced by Indium Zinc Oxide (IZO) trace layer and IZO electrode layer, etc. The cathode 24 can be made of silver, silver-magnesium (Mg) alloy, molybdenum (Mo), aluminum (AL), etc. It can be understood that the anode 22, the light-emitting layer 23 and the cathode 24 are not the whole surface structure, but have a patterned structure corresponding to the pixels. For more detailed description of the OLED display panel 20, please refer to the prior art, which will not be described here.

[0055] The liquid crystal display panel 10 comprises a first substrate 11, a second substrate 12 arranged opposite to the first substrate 11, and a liquid crystal layer 13 between the first substrate 11 and the second substrate 12, the first substrate 11 is located on the side of the liquid crystal layer 13 away from the OLED display panel 20, and the second substrate 12 is located on the side of the liquid crystal layer 13 facing the OLED display panel 20. In this embodiment, the liquid crystal molecules 131 in the liquid crystal layer 13 are positive liquid crystal molecules, that is, liquid crystal molecules with positive dielectric anisotropy. The liquid crystal molecules 131 are aligned parallel to the first substrate 11 and the second substrate 12, the alignment direction of the liquid crystal molecules 131 on the side close to the first substrate 11 is perpendicular to the alignment direction on the side close to the second substrate 12, and the liquid crystal molecules 131 are twisted by 90° or 270° from the side close to the first substrate 11 to the second substrate 12, so as to realize the TN display mode. The liquid crystal layer 13 has a phase delay of λ / 4 in the initial state, so that the reflective liquid crystal display device is in a bright state in the initial state, so as to realize the normal white mode in the reflective mode.

[0056] The first substrate 11 is provided with a linear polarizer 141 and a quarter-wave plate 142, the quarter-wave plate 142 is located on the side of the linear polarizer 141 facing the liquid crystal layer 13, and the transmission axis of the linear polarizer 141 and the fast and slow axes of the quarter-wave plate 142 (the fast axis and the slow axis of the quarter-wave plate 142 are perpendicular to each other) are at an angle of 45°. For example, the transmission axis of the linear polarizer 141 is 0°, the fast axis of the quarter-wave plate 142 is 45°, and the slow axis of the quarter-wave plate 142 is -45°.

[0057] In this embodiment, the second substrate 12 is provided with a control electrode 121, and the first substrate 11 is provided with a common electrode 112 matched with the control electrode 121. The control electrode 121 comprises a pixel electrode corresponding to each first pixel unit P1, and the common electrode 112 is a planar electrode covering the first substrate 11. The pixel electrode is used to apply a gray-scale voltage, so as to form a vertical electric field with the common electrode 112, thereby controlling the liquid crystal molecules 131 to perform a vertical deflection in the vertical direction. Of course, in other embodiments, the common electrode 112 can also be arranged on the second substrate 12 to form a fringe field switching mode (FFS) or an in-plane switching mode (IPS).

[0058] As Figure 2As shown, the second substrate 12 is provided with a plurality of scan lines 1 and a plurality of data lines 2 on the side facing the liquid crystal layer 13, the plurality of scan lines 1 and the plurality of data lines 2 are insulated and crossed with each other to define a plurality of first pixel units P1, each first pixel unit P1 is provided with a pixel electrode and a thin film transistor 3, the pixel electrode is electrically connected with the data line 2 adjacent to the thin film transistor 3 through the thin film transistor 3. The thin film transistor 3 includes a gate, an active layer, a drain and a source, the gate is located in the same layer as the scan line 1 and is electrically connected, the gate is insulated from the active layer through an insulating layer, the source is electrically connected with the data line 2, and the drain is electrically connected with the pixel electrode through a contact hole.

[0059] In the embodiment, the first substrate 11 is provided with a black matrix 111 and transparent areas, the black matrix 111 is used to separate the plurality of transparent areas from each other, the liquid crystal display panel 10 has the first pixel units P1 corresponding to the transparent areas, so that the black and white picture display is realized in the reflection mode. Further, as shown in Figure 1 As shown, the OLED display panel 20 has the second pixel units P2 corresponding to the light-emitting layer 23, wherein the first pixel units P1 can correspond to the second pixel units P2 one by one, of course, each first pixel unit P1 can also correspond to a plurality of second pixel units P2, or a plurality of first pixel units P1 correspond to one second pixel unit P2.

[0060] Further, the display device includes a diffuse reflection structure 122, the diffuse reflection structure 122 is arranged on the light-emitting side of the OLED display panel 20, the diffuse reflection structure 122 disperses the ambient light, so that the diffuse reflection effect is realized in the reflection mode, so as to improve the display effect. In the embodiment, the diffuse reflection structure 122 is arranged on the side of the second substrate 12 facing the liquid crystal layer 13, the diffuse reflection structure 122 has a plurality of convex structures, which is similar to the frosted structure, the diffuse reflection structure 122 can be made of OC material and is made on the side of the second substrate 12 facing the liquid crystal layer 13 by using nano-imprinting.

[0061] The first substrate 11, the second substrate 12 and the substrate 21 can be made of glass, acrylic and polycarbonate materials. The material of the control electrode 121 and the common electrode 112 can be indium tin oxide (ITO) or indium zinc oxide (IZO) and the like.

[0062] Figure 3 is a structural schematic diagram of the display device in the bright state in the reflection mode in the embodiment one of the present application. Figure 4 is a light path principle schematic diagram of the display device in the bright state in the reflection mode in the embodiment one of the present application. As shown in Figure 3As shown, in the bright state of the reflective mode, the OLED display panel 20 is turned off, no voltage is applied to the pixel electrode in the bright state area, and the liquid crystal molecules 131 in the liquid crystal layer 13 remain in the initial flat and twisted state. At this time, the liquid crystal layer 13 has a phase delay of λ / 4, and the ambient light reflected by the cathode 24 in the bright state area can be emitted from the linear polarizer 141. As shown in the figure, Figure 4 As shown, the ambient light I becomes linearly polarized light (for example, 0°) after passing through the linear polarizer 141, and the linearly polarized light becomes circularly polarized light (for example, left-handed) after passing through the quarter-wave plate 142. The circularly polarized light becomes linearly polarized light (for example, 0°) after passing through the liquid crystal layer 13, and the linearly polarized light does not change in polarization direction after being reflected by the cathode 24. The reflected light becomes circularly polarized light (for example, left-handed) after passing through the liquid crystal layer 13, and the circularly polarized light becomes linearly polarized light (for example, 0°) after passing through the quarter-wave plate 142, and then is emitted from the linear polarizer 141 to achieve the bright state of the reflective mode.

[0063] Figure 5 FIG. 4 is a structural schematic diagram of the display device in the dark state of the reflective mode in the first embodiment of the present application. Figure 6 FIG. 5 is a schematic diagram of the light path principle of the display device in the dark state of the reflective mode in the first embodiment of the present application. As shown in the figure, Figure 5 As shown, in the dark state of the reflective mode, the LED display panel 20 is turned off, a common voltage is applied to the common electrode 112, and a dark state voltage (for example, 5V) is applied to the pixel electrode in the dark state area. A strong vertical electric field (E1) is formed between the pixel electrode and the common electrode 112, Figure 5 The liquid crystal molecules 131 in the liquid crystal layer 13 are deflected in the vertical direction and are perpendicular to the first substrate 11 and the second substrate 12. At this time, the liquid crystal molecules 131 in the dark state area are all in the standing posture and have no phase delay, and the ambient light reflected by the cathode 24 in the dark state area is absorbed by the linear polarizer 141. As shown in the figure, Figure 6 As shown, the ambient light I becomes linearly polarized light (for example, 0°) after passing through the linear polarizer 141, and the linearly polarized light becomes circularly polarized light (for example, left-handed) after passing through the quarter-wave plate 142. The circularly polarized light is still circularly polarized light (for example, left-handed) after passing through the liquid crystal layer 13, and the circularly polarized light is opposite in rotation direction (becomes right-handed) after being reflected by the cathode 24. The reflected light is still circularly polarized light (for example, right-handed) after passing through the liquid crystal layer 13, and the circularly polarized light becomes linearly polarized light (for example, 90°) after passing through the quarter-wave plate 142, and then is absorbed by the linear polarizer 141 to achieve the dark state of the reflective mode.

[0064] Figure 7 FIG. 6 is a structural schematic diagram of the display device in the bright state of the transmissive mode in the first embodiment of the present application. Figure 8 FIG. 7 is a schematic diagram of the light path principle of the display device in the bright state of the transmissive mode in the first embodiment of the present application. As shown in the figure, Figure 7As shown, in transmission mode, the OLED display panel 20 is turned on and displays an image. The image displayed in transmission mode is controlled by the OLED display panel 20. A common voltage is applied to the common electrode 112, and a dark state voltage (e.g., 5V) is applied to all pixel electrodes, forming a strong vertical electric field between the pixel electrodes and the common electrode 112. Figure 7 In the liquid crystal layer 13 (E1), the liquid crystal molecules 131 in the liquid crystal layer 13 are deflected vertically and perpendicular to the first substrate 11 and the second substrate 12. At this time, all the liquid crystal molecules 131 are in an upright position and have no phase retardation. The ambient light reflected by the cathode 24 is absorbed by the linear polarizer 141, but the light emitted by the OLED display panel 20 can pass through the liquid crystal display panel 10. (Reference) Figure 6 As shown, for ambient light, ambient light I becomes linearly polarized (e.g., 0°) after passing through linear polarizer 141. The linearly polarized light then becomes circularly polarized (e.g., left-handed) after passing through quarter-wave plate 142. The circularly polarized light remains circularly polarized (e.g., left-handed) after passing through liquid crystal layer 13. After reflection by cathode 24, the circularly polarized light reverses its polarization (becomes right-handed). The reflected light remains circularly polarized (e.g., right-handed) after passing through liquid crystal layer 13. The circularly polarized light then becomes linearly polarized (e.g., 90°) after passing through quarter-wave plate 142, and is then absorbed by linear polarizer 141. Figure 8 As shown, the light emitted from the OLED display panel 20 (backlight) passes sequentially through the liquid crystal layer 13 and the quarter-wave plate 142 without change, then passes through the linear polarizer 141 to become linearly polarized light (e.g., 0°) and exits from the linear polarizer 141. This allows the light emitted from the OLED display panel 20 to pass through the liquid crystal display panel 10 and, in transmission mode, to control the displayed image through the OLED display panel 20. Furthermore, the ambient light reflected by the OLED display panel 20 is absorbed by the linear polarizer 141, thereby preventing the ambient light reflected by the OLED display panel 20 from reducing the contrast of the transmission display.

[0065] [Example 2]

[0066] Figure 9 This is one of the structural schematic diagrams of the display device in its initial state in Embodiment 2 of the present invention. Figure 10 This is the second schematic diagram of the display device in its initial state according to Embodiment 2 of the present invention. Figure 9 and Figure 10 The transmission and reflection switchable display device provided in Embodiment 2 of the present invention is similar to that in Embodiment 1. Figures 1 to 8 The display devices that can switch between transmission and reflection are basically the same, except that in this embodiment:

[0067] like Figure 9 As shown, the diffuse reflection structure 122 is disposed on the side of the second substrate 12 away from the liquid crystal layer 13. Alternatively, as... Figure 10As shown, the diffuse reflection structure 122 is arranged on the side of the OLED display panel 20 facing the liquid crystal display panel 10. That is, the diffuse reflection structure 122 is arranged between the liquid crystal display panel 10 and the OLED display panel 20, thereby avoiding the influence of the convex structure of the diffuse reflection structure 122 on the alignment of the liquid crystal layer 13, and causing the problem of Domain disorder. Of course, in other embodiments, the diffuse reflection structure 122 is also a PDLC (polymer dispersed liquid crystal) liquid crystal cell or a PNLC (Polymer Network Liquid Crystal) liquid crystal cell. The PDLC liquid crystal cell and the PNLC liquid crystal cell have scattering effect on light in the haze state, and can also achieve diffuse reflection effect in the reflection mode to improve the display effect.

[0068] Those skilled in the art should understand that the remaining structure and working principle of the embodiment are the same as those of Embodiment One, and will not be repeated here.

[0069] [Embodiment Three]

[0070] Figure 11 is a structural schematic diagram of the display device in the reflection mode dark state in Embodiment Three of the present application. Figure 12 is a structural schematic diagram of the display device in the reflection mode bright state in Embodiment Three of the present application. As shown in Figure 11 and Figure 12 The transmissive and reflective switchable display device provided in Embodiment Three of the present application is basically the same as the transmissive and reflective switchable display device in Embodiments One ( Figures 1 to 9 ), Two ( Figure 9 and Figure 10 ), and the difference is that, in the present embodiment:

[0071] As shown in Figure 11As shown, the first substrate 11 is provided with a common electrode 112 matched with the control electrode 121, the liquid crystal molecules 131 in the liquid crystal layer 13 are aligned perpendicularly to the first substrate 11 and the second substrate 12, when the liquid crystal molecules 131 are in a flat posture, the long axis of the liquid crystal molecules 131 is at 45° with the light transmission axis of the linear polarizer 141, at this time, the liquid crystal layer 13 has a phase delay of λ / 4. Further, the liquid crystal molecules 131 are negative liquid crystal molecules, i.e. liquid crystal molecules with negative dielectric anisotropy. The liquid crystal molecules 131 are aligned perpendicularly to the first substrate 11 and the second substrate 12 to realize a VA display mode. When the liquid crystal molecules 131 are in a flat posture, the long axis of the liquid crystal molecules 131 is at 45° with the light transmission axis of the linear polarizer 141, at this time, the liquid crystal layer 13 has a phase delay of λ / 4. The pre-tilt angle of the liquid crystal molecules 131 can be 80-90° to facilitate the deflection towards the flat posture and orient the deflection direction of the liquid crystal molecules 131. In this embodiment, by aligning the liquid crystal molecules 131 perpendicularly to the first substrate 11 and the second substrate 12, the liquid crystal display panel 10 can prevent the OLED display panel 20 from reflecting ambient light in the initial state, and in the transmissive display mode, it is not necessary to apply a driving voltage on the control electrode 121, which is more energy-saving.

[0072] Those skilled in the art should understand that the remaining structure and working principle of this embodiment are the same as those of Embodiment One and Embodiment Two, which will not be described here.

[0073] [Embodiment Two]

[0074] Figure 13 is a structural schematic diagram of the display device in the initial state in Embodiment Four of the application. Figure 14 is one of the planar structural schematic diagrams of the display device in Embodiment Four of the application. Figure 15 is one of the planar structural schematic diagrams of the control electrode in Embodiment Four of the application. Figure 16 is another of the planar structural schematic diagrams of the display device in Embodiment Four of the application. Figure 17 is another of the planar structural schematic diagrams of the control electrode in Embodiment Four of the application. Figures 13 to 17 As shown, the transmissive and reflective switchable display device provided by Embodiment Two of the application is basically the same as the transmissive and reflective switchable display device in Embodiment One ( Figures 1 to 8 ), Embodiment Two ( Figure 9 and Figure 10 ), Embodiment Three ( Figure 11 and Figure 12 ), and the difference is that, in this embodiment:

[0075] The display device has a pattern area 110 and a background area 120, the control electrode 121 includes a first electrode 121a and a second electrode 121b which are insulated from each other, the first electrode 121a corresponds to the pattern area 110, and the second electrode 121b corresponds to the background area 120. As shown in Figure 14 and Figure 15 The pattern area 110 can be an identification pattern, such as a product logo; as shown in Figure 16 and Figure 17 The pattern area 110 can also be a clock pattern, so as to display time by ambient light when the screen is off. Since the control electrode 121 in the present application includes the first electrode 121a corresponding to the pattern area 110 and the second electrode 121b corresponding to the background area 120, the control logic of the control electrode 121 is simpler, and the circuit design on the second substrate 12 can be simplified.

[0076] Figure 18 is a structural schematic diagram of the display device in the screen-off display state in the fourth embodiment of the present application. As shown in Figure 18 In the screen-off display state, the OLED display panel 20 is turned off, the common electrode 112 is applied with a common voltage, the first electrode 121a is not applied with a voltage, the liquid crystal molecules 131 corresponding to the pattern area 110 remain in the initial flat and twisted state, at this time, the liquid crystal layer 13 has a phase delay of λ / 4, the ambient light reflected by the cathode 24 in the pattern area 110 can be emitted from the linear polarizer 141, so as to make the pattern area 110 in a bright state; the second electrode 121b is applied with a dark state voltage (for example, 5V), a strong vertical electric field is formed between the second electrode 121b and the common electrode 112, the liquid crystal molecules 131 corresponding to the background area 120 are deflected in the vertical direction and are perpendicular to the first substrate 11 and the second substrate 12, at this time, the liquid crystal molecules 131 of the background area 120 are in a standing posture and have no phase delay, the ambient light reflected by the cathode 24 in the background area 120 is absorbed by the linear polarizer 141, so as to make the pattern area 110 in a dark state. Therefore, the bright state pattern corresponding to the pattern area 110 can be displayed when the screen is off. Of course, in other embodiments, in the screen-off display state, the first electrode 121a can be applied with a dark state voltage (for example, 5V), and the second electrode 121b is not applied with a voltage, so as to display the dark state pattern corresponding to the pattern area 110 when the screen is off.

[0077] Those skilled in the art should understand that the remaining structure and working principle of the present embodiment are the same as those of the first embodiment, the second embodiment and the third embodiment, and will not be described here.

[0078] [Embodiment Five]

[0079] Figure 19 is a structural schematic diagram of the display device in the initial state in the fifth embodiment of the present application. Figure 20This is a schematic diagram of the planar structure of the first substrate in Embodiment 5 of the present invention. Figure 21 This is a schematic diagram of the planar structure of the OLED display panel in Embodiment 5 of the present invention. Figures 19 to 21 As shown, the display device with switchable transmission and reflection provided in Embodiment 5 of the present invention is similar to that in Embodiment 1 (… Figures 1 to 8 Example 2 Figure 9 and Figure 10 Example 3 Figure 11 and Figure 12 Example 4 Figures 13 to 18 The display devices that can switch between transmission and reflection are basically the same, except that in this embodiment:

[0080] like Figures 19 to 21 As shown, the first substrate 11 is provided with a black matrix 111 and a color resist layer 113. The black matrix 111 is used to separate multiple color resist layers 113 from each other. The color resist layer 113 includes red, green and blue color resist materials, which correspond to red, green and blue pixels respectively, so that the display device can realize full-color reflective display.

[0081] Furthermore, the liquid crystal display panel 10 has a first pixel unit P1 corresponding to the color resist layer 113, and the OLED display panel 20 has a second pixel unit P2 corresponding to the light-emitting layer 23. The first pixel unit P1 and the second pixel unit P2 are in one-to-one correspondence. Since the first substrate 11 in this embodiment is a color filter substrate, in order not to affect the display of the color image on the OLED display panel 20, the first pixel unit P1 and the second pixel unit P2 need to be in one-to-one correspondence, and the colors of the first pixel unit P1 and the second pixel unit P2 also need to correspond, that is, the red first pixel unit P1 corresponds to the red second pixel unit P2, the green first pixel unit P1 corresponds to the green second pixel unit P2, and the blue first pixel unit P1 corresponds to the blue second pixel unit P2.

[0082] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4, and will not be repeated here.

[0083] [Example 6]

[0084] Figure 22 This is a schematic diagram of the display device in its initial state according to Embodiment Six of the present invention. Figure 22 As shown, the display device with switchable transmission and reflection provided in Embodiment Six of the present invention is similar to that in Embodiment One (…). Figures 1 to 8 Example 2 Figure 9 and Figure 10 Example 3 Figure 11 and Figure 12 Example 4Figures 13 to 18 ), the transmissive and reflective switchable display device in example five ( Figures 22 to 24 ) is basically the same, the difference is that in the present embodiment:

[0085] The liquid crystal layer 13 comprises liquid crystal molecules 131 and nano-particles 132 mixed with each other, the refractive index of the nano-particles 132 is different from that of the liquid crystal molecules 131, the nano-particles 132 cooperate with the liquid crystal molecules 131 and can reflect and scatter light. Since the nano-particles 132 can scatter light after cooperating with the liquid crystal molecules 131, the diffuse reflection structure 122 can be omitted in the present embodiment, so that the thickness of the display device is thinner. Moreover, the nano-particles 132 can also reflect light after cooperating with the liquid crystal molecules 131, so that the utilization rate of ambient light in the reflective mode can be improved, and the contrast of the reflective display can be improved.

[0086] The proportion of the nano-particles 132 in the liquid crystal layer 13 is 45% to 65%, and the proportion is preferably 50%. The diameter of the nano-particles 132 is 5nm to 500nm, the nano-particles 132 are in white or transparent state, the nano-particles 132 can increase the reflection and scattering effect of incident light, improve the reflectivity of the display device as a whole, and increase the viewing angle. The nano-particles 132 can be made of inorganic or organic materials and uniformly dispersed in the liquid crystal layer 13 and stably exist. The refractive index of the nano-particles 132 is different from that of the liquid crystal molecules 131, and the difference between the refractive index of the nano-particles 132 and that of the liquid crystal molecules 131 is preferably above 0.1, so as to increase the reflection and refraction at the interface between the liquid crystal molecules 131 and the nano-particles 132. Of course, in actual application, the specific material of the nano-particles 132 can be selected according to actual needs, as long as the material meets the requirements of different refractive index from the liquid crystal molecules 131, diameter of 5nm to 500nm, and white or transparent.

[0087] Figure 23 is a structural schematic diagram of the spherical nano-particles and the liquid crystal molecules in the present embodiment. Figure 24 is a structural schematic diagram of the strip-shaped nano-particles and the liquid crystal molecules in the present embodiment. As shown in Figure 23 , the nano-particles 132 can be in spherical structure with a diameter of 5nm to 500nm, the nano-particles 132 can be organic macromolecules and uniformly dispersed in combination with the liquid crystal molecules 131; of course, the nano-particles 132 can also be inorganic nano-particles, such as SiOx particles, etc. As shown in Figure 24 , the nano-particles 132 can also be in strip-shaped structure, such as carbon nanotubes, glass fibers, etc., and uniformly mixed with the liquid crystal molecules 131, the diameter of the nano-particles 132 is 5nm to 20nm, and the length is 5nm to 500nm.

[0088] Those skilled in the art should understand that the remaining structure and working principle of the embodiment are the same as those of Embodiment 1, Embodiment 2, Embodiment 3, Embodiment 4, and Embodiment 5, and will not be described here.

[0089] In this article, the orientation words such as up, down, left, right, front, back and the like are defined according to the position of the structure in the drawing and the position of the structure relative to each other in the drawing, just to express the technical solution clearly and conveniently. It should be understood that the use of the orientation words should not limit the scope of the application. It should also be understood that the terms "first" and "second" used herein are only used for name distinction and do not limit the quantity and order.

[0090] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the disclosed technical content without departing from the scope of the technical solution of the present application, and any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A display device that can switch between transmission and reflection, characterized in that, Includes an OLED display panel (20) and a liquid crystal display panel (10) disposed on the light-emitting side of the OLED display panel (20); The liquid crystal display panel (10) includes a first substrate (11), a second substrate (12) disposed opposite to the first substrate (11), and a liquid crystal layer (13) located between the first substrate (11) and the second substrate (12). The first substrate (11) is located on the side of the liquid crystal layer (13) away from the OLED display panel (20), and the second substrate (12) is located on the side of the liquid crystal layer (13) facing the OLED display panel (20). A linear polarizer (141) and a quarter-wave plate (142) are provided on the first substrate (11). The quarter-wave plate (142) is located on the side of the linear polarizer (141) facing the liquid crystal layer (13). The light transmission axis of the linear polarizer (141) is at a 45° angle to the fast and slow axis of the quarter-wave plate (142). A control electrode (121) is provided on the second substrate (12). A common electrode (112) cooperating with the control electrode (121) is provided on the first substrate (11) or the second substrate (12). The liquid crystal layer (13) includes liquid crystal molecules (131) and nanoparticles (132) that are mixed together. The refractive index of the nanoparticles (132) is different from that of the liquid crystal molecules (131). The nanoparticles (132) and the liquid crystal molecules (131) cooperate with each other and can reflect and scatter light. The OLED display panel (20) includes a substrate (21) and an anode (22), a light-emitting layer (23) and a cathode (24) sequentially disposed on the substrate (21). The anode (22) and the cathode (24) are used to control the light-emitting state of the light-emitting layer (23). In transmission mode, the liquid crystal molecules (131) in the entire liquid crystal layer (13) are all in an upright position. The ambient light reflected by the cathode (24) is absorbed by the linear polarizer (141). The OLED display panel (20) is turned on and displays an image. The light emitted by the OLED display panel (20) can pass through the liquid crystal display panel (10). In reflection mode, the OLED display panel (20) is turned off. The liquid crystal molecules (131) in the liquid crystal layer (13) in the dark region are all in an upright position. The ambient light reflected by the cathode (24) in the dark region is absorbed by the linear polarizer (141). The liquid crystal molecules (131) in the liquid crystal layer (13) in the bright region are all in a lying position and have a phase delay of λ / 4. The ambient light reflected by the cathode (24) in the bright region can be emitted from the linear polarizer (141).

2. The display device with switchable transmission and reflection according to claim 1, characterized in that, The display device includes a diffuse reflection structure (122), which is disposed on the light-emitting side of the OLED display panel (20).

3. The display device with switchable transmission and reflection according to claim 2, characterized in that, The diffuse reflection structure (122) is disposed on the side of the second substrate (12) facing the liquid crystal layer (13); Alternatively, the diffuse reflection structure (122) may be disposed on the side of the second substrate (12) away from the liquid crystal layer (13); Alternatively, the diffuse reflection structure (122) may be disposed on the side of the OLED display panel (20) facing the liquid crystal display panel (10).

4. The display device with switchable transmission and reflection according to claim 2, characterized in that, The diffuse reflection structure (122) has multiple protrusions, or the diffuse reflection structure (122) is a PDLC liquid crystal cell or a PNLC liquid crystal cell.

5. The display device with switchable transmission and reflection according to claim 1, characterized in that, The second substrate (12) is provided with multiple scan lines (1), multiple data lines (2) and multiple thin film transistors (3). The scan lines (1) and the data lines (2) are mutually insulated and cross each other to form multiple first pixel units (P1) distributed in a matrix. The control electrode (121) includes pixel electrodes that correspond one-to-one with the first pixel units (P1). The pixel electrodes are electrically connected to the scan lines (1) and the data lines (2) adjacent to the thin film transistors (3) through the thin film transistors (3).

6. The display device with switchable transmission and reflection according to claim 1, characterized in that, The display device has a pattern area (110) and a background area (120). The control electrode (121) includes a first electrode (121a) and a second electrode (121b) that are insulated from each other. The first electrode (121a) corresponds to the pattern area (110), and the second electrode (121b) corresponds to the background area (120).

7. The display device with switchable transmission and reflection according to any one of claims 1-6, characterized in that, The first substrate (11) is provided with a black matrix (111) and a color resist layer (113). The black matrix (111) is used to separate the multiple color resist layers (113) from each other. The liquid crystal display panel (10) has a first pixel unit (P1) corresponding to the color resist layer (113). The OLED display panel (20) has a second pixel unit (P2) corresponding to the light-emitting layer (23). The first pixel unit (P1) and the second pixel unit (P2) correspond one-to-one.

8. The display device with switchable transmission and reflection according to any one of claims 1-6, characterized in that, The first substrate (11) is provided with a common electrode (112) that cooperates with the control electrode (121). The liquid crystal molecules (131) in the liquid crystal layer (13) are aligned parallel to the first substrate (11) and the second substrate (12). The alignment direction of the liquid crystal molecules (131) on the side closer to the first substrate (11) is perpendicular to the alignment direction on the side closer to the second substrate (12). The liquid crystal layer (13) has a phase delay of λ / 4 in the initial state. Alternatively, the first substrate (11) is provided with a common electrode (112) that cooperates with the control electrode (121). The liquid crystal molecules (131) in the liquid crystal layer (13) are aligned perpendicular to the first substrate (11) and the second substrate (12). When the liquid crystal molecules (131) are in a flat position, the long axis of the liquid crystal molecules (131) is at 45° with the light transmission axis of the linear polarizer (141). At this time, the liquid crystal layer (13) has a phase delay of λ / 4.

9. The display device with switchable transmission and reflection according to claim 1, characterized in that, The refractive index of the nanoparticles (132) differs from that of the liquid crystal molecules (131) by more than 0.

1. And / or, the nanoparticles (132) are spherical or strip-shaped structures; And / or, the diameter of the nanoparticles (132) is 5 nm to 500 nm; And / or, the nanoparticles (132) are white or transparent.

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