Display device and mobile terminal including the same

Abstract

The disclosure relates to a display device and a mobile terminal including the same, and includes a first display panel including a first pixel array area and a light transmission area, a second display panel disposed below the first display panel and including a second pixel array area overlapping the light transmission area, and a light guide module disposed between the light transmission area of the first display panel and the second pixel array area of the second display panel to transmit light from the second pixel array area to the light transmission area and refract external light incident through the light transmission area to the outside of the second pixel array area.

Description

Technical Field

[0001] This disclosure relates to a display device and a mobile terminal including the display device. Background Technology

[0002] Based on the material of the light-emitting layer, electroluminescent display devices can be divided into inorganic light-emitting display devices and organic light-emitting display devices. Active-matrix organic light-emitting display devices include self-emissive organic light-emitting diodes (hereinafter referred to as OLEDs) and have advantages such as fast response speed, high luminous efficiency and brightness, and wide viewing angle. In organic light-emitting display devices, an OLED (organic light-emitting diode, referred to as OLED) is formed in each pixel. Organic light-emitting display devices have fast response speed, excellent luminous efficiency, brightness and viewing angle, and because they can display black grayscale, they have excellent contrast and color reproduction.

[0003] Multimedia capabilities of mobile devices have been improved. For example, smartphones now have cameras embedded by default, and the resolution of these cameras has been increased to the level of existing digital cameras. The front camera of smartphones limits screen design, making screen design difficult. To reduce the space occupied by the camera, screen designs including notches or punch-holes have been used in smartphones; however, due to the camera, screen size is still limited, making full-screen display impossible. Summary of the Invention

[0004] To achieve full-screen display, pixels arranged at a lower pixel per inch (PPI) can be placed in the pixel area overlapping with the camera below the display panel. While light transmittance may increase in low-PPI pixel areas, the images captured by the camera may be blurry due to the presence of pixels in these low-PPI areas, thus potentially degrading the image quality. Image quality compensation algorithms can improve image quality degradation but cannot completely eliminate image quality degradation caused by pixel interference.

[0005] The purpose of this disclosure is to address the aforementioned needs and / or problems.

[0006] This disclosure provides a display device and a mobile terminal including the display device to achieve full-screen display and improve the quality of images captured by a camera.

[0007] The problems to be solved by this disclosure are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

[0008] A display device according to an embodiment of the present disclosure includes: a first display panel including a first pixel array region and a light-transmitting region; a second display panel disposed below the first display panel and including a second pixel array region overlapping the light-transmitting region; and a light guide module disposed between the light-transmitting region of the first display panel and the second pixel array region of the second display panel to transmit light from the second pixel array region to the light-transmitting region and refract external light incident through the light-transmitting region away from the second pixel array region.

[0009] A display device according to another embodiment of the present disclosure includes: a display panel comprising a first pixel array region, a light-transmitting region, and a second pixel array region; and a light guide module disposed below the light-transmitting region. The portion of the display panel having the second pixel array region is folded behind the light guide module, such that the second pixel array region faces the light guide module. The light guide module includes a switchable liquid crystal lens disposed between the light-transmitting region and the second pixel array region and includes a liquid crystal layer, to which an electric field is applied according to a liquid crystal driving voltage.

[0010] A mobile terminal according to an embodiment of the present disclosure includes: a display panel including a first pixel array region, a light-transmitting region, and a second pixel array region; a light guide module disposed below the light-transmitting region; an optical sensor module arranged at a position avoiding the light-transmitting region and including one or more optical sensors, wherein external light refracted by the light guide module is incident on the one or more optical sensors; a display module for writing pixel data of an input image into the first and second pixel arrays; and a host system for transmitting the photo data received from the optical sensor module to the display module. The light guide module transmits light from the second pixel array region toward the light-transmitting region and refracts external light incident through the light-transmitting region toward the optical sensor module.

[0011] According to an embodiment of the present disclosure, the display device includes: a first display panel, the first display panel including a first pixel array region and a light-transmitting region, wherein a switchable liquid crystal lens overlapping the light-transmitting region is embedded in the first pixel array region; and a second display panel, the second display panel being disposed below the first display panel and including a second pixel array region overlapping the light-transmitting region, wherein the switchable liquid crystal lens transmits light from the second pixel array region to the light-transmitting region and refracts external light incident through the light-transmitting region away from the second pixel array region.

[0012] According to this disclosure, since the optical sensor module is located in the screen where the image is displayed, full-screen display can be achieved.

[0013] Because there are no pixels or circuit elements in the optical path of external light traveling to the optical sensor module, this disclosure can improve the quality of captured images obtained from the optical sensor module.

[0014] When a user creates a selfie or selfie image using a mobile terminal such as a smartphone, this disclosure can minimize interference from external light incident on the optical sensor module, thereby improving the quality of the selfie image.

[0015] By using data received from the optical sensor module, this disclosure can minimize noise in the output data of the optical sensor module when processing user biometric authentication (e.g., user facial authentication), thereby preventing errors in user authentication processing.

[0016] The effects of this disclosure are not limited to those described above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description and the appended claims. Attached Figure Description

[0017] The above and other objects, features, and advantages of this disclosure will become more apparent to those skilled in the art from the detailed description of exemplary embodiments thereof with reference to the accompanying drawings, wherein: Figure 1 This is a view showing the screen of a mobile terminal according to an embodiment of the present disclosure; Figure 2 This is a cross-sectional view schematically showing the pixel array and light-transmitting area of ​​a display panel according to an embodiment of the present disclosure; Figure 3 and Figure 4 It is a cross-sectional view showing in detail the cross-sectional structure of the pixel array of a display panel according to various embodiments of the present disclosure; Figure 5 This is a block diagram illustrating the configuration of the driving unit of a mobile terminal according to an embodiment of the present disclosure; Figure 6A and Figure 6B This is a cross-sectional view showing in detail the structure of the display panel and the light guide module according to the first embodiment of the present disclosure; Figure 7 This is a cross-sectional view showing in detail the structure of the display panel and the light guide module according to the second embodiment of this disclosure; Figure 8 This is a cross-sectional view showing in detail the structure of the display panel and the light guide module according to the third embodiment of this disclosure; Figure 9 and Figure 10 This is a cross-sectional view showing in detail the structure of the display panel and the light guide module according to the fourth embodiment of this disclosure. Detailed Implementation

[0018] The advantages and features of this disclosure, as well as the methods for implementing this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings. However, this disclosure is not limited to the following embodiments, but can be implemented in various different forms. Rather, these embodiments will complete the disclosure and allow those skilled in the art to fully understand its scope. This disclosure is limited only to the scope of the appended claims.

[0019] The shapes, dimensions, ratios, angles, quantities, etc., shown in the accompanying drawings to describe embodiments of this disclosure are merely examples, and this disclosure is not limited thereto. Throughout the specification, the same reference numerals generally denote the same elements. Furthermore, in describing this disclosure, detailed descriptions of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of this disclosure.

[0020] Terms used herein, such as “comprising,” “including,” “having,” and “consisting of,” are generally intended to allow for the addition of other components, unless the term is used in conjunction with the term “only.” Unless otherwise expressly stated, any reference to the singular may include the plural.

[0021] The component is interpreted to include the normal error range, even if not explicitly stated otherwise.

[0022] When using terms such as “above,” “over,” “below,” and “under” to describe the positional relationship between two parts, one or more parts may be located between the two parts, unless the term is used with the terms “immediately” or “directly.”

[0023] The terms “first”, “second”, etc., can be used to distinguish components from each other, but the function or structure of a component is not limited by the ordinal number preceding the component or the component name.

[0024] In this disclosure, the same reference numerals may refer to substantially the same elements.

[0025] The following implementation methods may be combined or integrated with each other in part or in whole, and may be connected and operated in technically different ways. The implementation methods may be performed independently of each other or in relation to each other.

[0026] Each pixel can include multiple subpixels of different colors to reproduce the colors of an image on the screen of the display panel. Each subpixel includes a transistor that functions as a switching element or a driving element. This transistor can be implemented as a TFT (thin-film transistor).

[0027] In the following, various embodiments of this disclosure will be described in detail with reference to the accompanying drawings.

[0028] refer to Figure 1 and Figure 2 The screen of the mobile terminal 1000 is implemented as display panels 100 and 300 of a display device. Display panels 100 and 300 include a first display panel 100 and a second display panel 300. The first display panel 100 is exposed to the outside and displays most of the input image. The second display panel 300 is disposed below the first display panel 100 and is not exposed to the outside. The second display panel 300 displays a portion of the input image.

[0029] The first display panel 100 and the second display panel 300 can be manufactured integrated or separately to be physically separated. Each of the display panels 100 and 300 can be implemented as a flexible display panel, wherein pixels are disposed on a flexible substrate such as a plastic substrate, but is not limited thereto.

[0030] The pixel array regions PA1 and PA2 in the first display panel 100 and the second display panel 300 include multiple data lines, gate lines intersecting the data lines, and pixels connected to the data lines and gate lines. Each pixel includes a light-emitting element EL, a driving element for driving the light-emitting element EL, one or more switching elements, and a capacitor for storing the gate-source voltage of the driving element. Pixel arrays PA1 and PA2 can be implemented as active matrix pixel arrays, wherein each pixel includes a switching element. In another embodiment, the first pixel array region PA1 can be implemented as an active matrix pixel array, while the second pixel array region PA2 can be implemented as a passive matrix pixel array without switching elements.

[0031] The first display panel 100 includes a first pixel array region PA1 and a light-transmitting region UDC that does not have pixels. Pixel data of the input image is written into the first pixel array region PA1. The light-transmitting region UDC does not have pixels. Figure 3 and Figure 4 The circuit layer 12 is shown. The light-transmitting area UDC can be set in the first pixel array area PA1.

[0032] The second display panel 300 includes at least a second pixel array region PA2 that overlaps with the light-transmitting region UDC of the first display panel 100. The second pixel array region PA2 includes pixels that contain some pixel data of the input image and displays a portion of the input image that cannot be reproduced in the light-transmitting region UDC of the first display panel 100. Therefore, the input image can be reproduced as a combination of the images displayed in the first pixel array region PA1 and the second pixel array region PA2.

[0033] In the light-transmitting area UDC of the first display panel 100, there is no opaque material layer that does not block or interfere with light. Therefore, light emitted from the pixels of the second display panel 300 can propagate to the outside through the light-transmitting area UDC, and light from the outside can pass through the light-transmitting area UDC and propagate downwards to the first display panel 100.

[0034] The display device includes a light guide module 200 disposed between a first display panel 100 and a second display panel 300, and an optical sensor module 400 configured to avoid the light-transmitting area UDC so as not to overlap with the light-transmitting area UDC.

[0035] The optical sensor module 400 may include one or more optical sensors, such as an imaging module (or camera) including an image sensor, an infrared sensor module, and an illuminance sensor module. The optical sensor module 400 may be positioned below the first display panel 100 to avoid the light-transmitting area UDC, i.e., it does not overlap with the light-transmitting area UDC. The optical sensor module 400 does not overlap with the second pixel array area PA2. The optical sensor module 400 may overlap with the first pixel array area PA1, but is not limited thereto. The optical sensor module 400 may be coplanar with the second display panel 300.

[0036] A light guide module 200 is disposed between the light-transmitting area UDC of the first display panel 100 and the second pixel array area PA2 of the second display panel 300, so that light from the second pixel array area PA2 passes through the light-transmitting area UDC. On the other hand, the light guide module 200 refracts external light incident through the light-transmitting area UDC of the first display panel 100 away from the second pixel array area PA2. The external light refracted by the light guide module 200 can proceed to the optical sensor module 400, which is configured to avoid the light-transmitting area UDC. Therefore, since there are no pixels or wires connected to pixels in the optical path of the external light guided to the optical sensor module 400, the external light can be incident on the optical sensor module 400 without interference.

[0037] The light emitted from the second pixel array region PA2 passes through the light guide module 200 and propagates to the outside. When a user views the screen of the display device from the outside, he or she can see a perfectly reproduced image with minimal quality difference between the image reproduced on the first display panel 100 and the image reproduced on the second display panel 300.

[0038] like Figure 3 and Figure 4 As shown, the cross-sectional structure of the pixel array of the first display panel 100 may include a circuit layer 12, a light-emitting element layer 14, and an encapsulation layer 16 stacked on the substrate 10.

[0039] Circuit layer 12 may include circuitry required to drive pixels, such as pixel circuitry connected to lines such as data lines, gating lines, and power lines. The wires and circuit elements of circuit layer 12 may include multiple insulating layers, two or more metal layers separated by insulating layers, and active layers of transistors comprising semiconductor materials.

[0040] The light-emitting element layer 14 may include light-emitting elements EL driven by pixel circuitry. The light-emitting elements (hereinafter referred to as EL) may include red (R) light-emitting elements, green (G) light-emitting elements, and blue (B) light-emitting elements. In another embodiment, the light-emitting element layer 14 may include a white light-emitting element and a color filter. The light-emitting elements EL of the light-emitting element layer 14 may be covered by a passivation layer comprising an organic film and a passivation film.

[0041] Encapsulation layer 16 covers light-emitting element layer 14 to seal circuit layer 12 and light-emitting element layer 14. Encapsulation layer 16 may have a multi-insulating film structure in which organic film PCL and inorganic films PAS1 and PAS2 are alternately stacked. Inorganic films PAS1 and PAS2 block the penetration of moisture or oxygen. Organic film PCL flattens the surfaces of inorganic films PAS1 and PAS2. When organic film PCL and inorganic films PAS1 and PAS2 are stacked in multiple layers, the movement path of moisture or oxygen becomes longer than that of a single layer, thereby effectively blocking the penetration of moisture and oxygen that affect light-emitting element layer 14.

[0042] The touch sensor layer 18 is formed on the encapsulation layer 16, and Figure 3 The polarizer 20 shown is or Figure 4 The color filter layer 24 shown can be disposed on the touch sensor layer 18. The touch sensor layer 18 may include a capacitive touch sensor that senses touch input based on capacitance changes before and after the touch input.

[0043] The touch sensor layer 18 may include a metal wiring pattern 19 and insulating films INS1 and INS2 forming the capacitor of the touch sensor. The insulating films INS1 and INS2 can insulate the portions intersecting with the metal wiring pattern 19 and can planarize the surface of the touch sensor layer.

[0044] Polarizer 20 converts the polarization of external light reflected by the metal of touch sensor layer 18 and circuit layer 12 to improve visibility and contrast. Polarizer 20 can be implemented as a polarizer in which a linear polarizer and a phase retardation film are bonded or a circular polarizer. A cover glass can be adhered to the polarizer. A linear polarizer can be interpreted as a half-wave plate (hereinafter referred to as HWP), while a circular polarizer can be interpreted as a quarter-wave plate (hereinafter referred to as QWP).

[0045] Adhesive 31 is applied to polarizer 20 so that cover glass 32 can adhere thereto. Adhesive 31 may be an optically transparent adhesive (hereinafter referred to as OCA).

[0046] Color filter layer 24 may include a red color filter CF_R, a green color filter CF_G, and a blue color filter CF_B. Color filter layer 24 may also include a black background pattern BM. Color filter layer 24 can absorb a portion of the wavelength of light reflected from circuit layer 12 and touch sensor layer 18, replacing the function of polarizer 20, and can improve the color purity of the image reproduced in the first pixel array region PA1. Therefore, in Figure 4 In the cross-sectional structure shown, polarizer 20 is not required.

[0047] The color filter layer 24 may include an organic film PAC covering the color filters CF_R, CF_G, and CF_B, as well as the black background pattern BM, and planarizing the surface of the color filter layer 24. The cover glass 32 may be adhered to the organic film PAC of the color filter layer 24.

[0048] The cross-sectional structure of the pixel array of the second display panel 300 can be the same as that of the pixel array of the first display panel 100, or it can be a different structure. For example, at least one of the touch sensor layer 18, polarizer 20, and color filter layer 24 can be removed from the second display panel 300.

[0049] Figure 5 This is a block diagram illustrating the configuration of the driving unit of a mobile terminal according to an embodiment of the present disclosure.

[0050] Reference Figure 5 The host system 50 of the mobile terminal can be connected to a power module, sensor module, communication module, display module, etc. The sensor module includes an optical sensor module 400. The host system 50 may include an application processor (hereinafter referred to as AP).

[0051] The host system 50 scales the input image to fit the resolution of the first pixel array area PA1 and the second pixel array area PA2 of the display panel, and sends the scaled input image to the display module.

[0052] The host system 50 can reproduce a photographic image on the screen by sending photographic data received from the imaging module of the optical sensor module 400 to the display module. The host system 50 can determine the brightness of the operating environment of the mobile terminal 1000 based on data from the illuminance sensor of the optical sensor module 400, and can adjust the brightness of the image reproduced on the screen. The host system 50 can process user facial authentication based on data received from the infrared sensor module of the optical sensor module 400.

[0053] The display module includes a display controller 52 and a display panel driver 54 to write pixel data of an input image to a first pixel array PA1 and a second pixel array PA2. The display controller 52 sends pixel data of the input image received from the host system 50 to the display panel driver 54.

[0054] The display panel driver 54 includes: a data driver that converts pixel data received from the display controller 52 into a gamma-compensated voltage to output a data voltage; and a gating driver that outputs a gating signal such as a scan pulse. The data voltage of the pixel data is provided to the data lines of pixel array regions PA1 and PA2. The gating signal is provided to the gating lines of pixel array regions PA1 and PA2. The display panel driver 54 may also include a touch sensor driver. The display controller 52 may include a timing controller that controls the operating timing of the display panel driver 54.

[0055] The host system 50 or display controller 52 can control the lens driver 56 and the optical sensor driver 58.

[0056] The lens driver 56 drives the switchable liquid crystal lens of the light guide module 200 under the control of the host system 50 or the display controller 52, so that external light is refracted toward the optical sensor module 400, while driving light emitted from the pixels of the second display panel 300 passes through.

[0057] The optical sensor driver 58 drives each optical sensor of the optical sensor module 400 under the control of the host system 50 or the display controller 52, and sends the output data of the optical sensor to the host system 50.

[0058] Figure 6A and Figure 6B This is a cross-sectional view showing in detail the structure of the display panel and the light guide module according to the first embodiment of this disclosure.

[0059] Reference Figure 6A and Figure 6B The first display panel 100 includes a first pixel array region PA1, a linear polarizer 22, and a first circular polarizer 21.

[0060] The first pixel array region PA1 includes at least a circuit layer 12, a light-emitting element layer 14, and an encapsulation layer 16, and displays most of the input image. A transparent portion 101 without pixels and circuit elements is disposed in the light-transmitting region UDC of the first display panel 100. The transparent portion 101 is made only of a transparent insulating material, such as the organic film and / or inorganic film in the circuit layer 12 and the light-emitting element layer 14.

[0061] Linear polarizer 22 and first circular polarizer 21 can cover the light-transmitting region UDC and the display area in which the first pixel array region PA1 is disposed. In the light-transmitting region UDC, the first circular polarizer 21 can be disposed between the linear polarizer 22 and the transparent portion 101. The linear polarizer 22 and the first circular polarizer 21 can be patterned to be disposed only in the light-transmitting region UDC. The linear polarizer 22 allows linearly polarized light from the incident light propagating along a first optical axis (e.g., a horizontal optical axis) to pass through. The linear polarizer 22 can be a half-wave plate (HWP). By delaying the phase of the linearly polarized light by 45 degrees, the light passing through the first circular polarizer 21 is converted into circularly polarized light.

[0062] The second display panel 300 overlaps with the first display panel 100, and the light guide module 200 is placed between them. The second pixel array region PA2 overlaps with the light-transmitting region UDC to display an image in the light-transmitting region UDC.

[0063] The light guide module 200 is disposed below the light-transmitting area UDC of the first display panel 100. The light guide module 200 may include a switchable liquid crystal lens 220 and a second circular polarizer 210 disposed between the switchable liquid crystal lens 220 and the first display panel 100.

[0064] The first circular polarizer 21 and the second circular polarizer 210 overlap with the transparent portion 101 of the first display panel 100 inserted therebetween. The second circular polarizer 210 delays the phase of the circularly polarized light incident from the first circular polarizer 21 by 45 degrees, converting it into linearly polarized light propagating along a second optical axis (e.g., perpendicular to the optical axis). The second circular polarizer 210 also delays the phase of the linearly polarized light incident from the convertible liquid crystal lens 220 by 45 degrees, converting it into circularly polarized light.

[0065] The switchable liquid crystal lens 220 includes a first transparent electrode 221 formed on a first transparent substrate, a second transparent electrode 224 formed on a second transparent substrate, and a lens 223 and a liquid crystal layer 222 formed between the first and second transparent substrates. An alignment film may be formed on at least one of the first and second transparent substrates. In another embodiment, when the first transparent electrode 221 and the second transparent electrode 224 are patterned along a specific alignment direction, for example, when patterned as stripes, the alignment film may be omitted.

[0066] The first transparent electrode 221 and the second transparent electrode 224 face each other, with the liquid crystal layer 222 inserted between them to form an electric field in the liquid crystal layer 222 according to the liquid crystal driving voltage. The liquid crystal layer 222 can selectively refract incident light using the anisotropy of the refractive index of the liquid crystal molecules to adjust the light path. The liquid crystal layer 222 can be implemented in a vertically aligned nematic liquid crystal (hereinafter referred to as VA) mode or other liquid crystal modes. The first transparent electrode 221 and the second transparent electrode 224 of the switchable liquid crystal lens 220 can be formed of indium tin oxide (hereinafter referred to as ITO), but are not limited thereto.

[0067] Lens 223 can be formed from an insulating material with a suitable refractive index in an organic or inorganic film formed on the circuit layer 12 and the light-emitting element layer 14. Due to its different refractive index from that of the liquid crystal layer 222, lens 223 refracts external light passing through the liquid crystal layer 222.

[0068] exist Figure 6A and Figure 6B In this context, "SW" represents a switching element used to apply a liquid crystal driving voltage from the lens driver 56. In display mode, the switching element SW is off, while in optical sensor driving mode, the switching element SW is on to form an electric field in the liquid crystal layer 222. The refractive index of the switchable liquid crystal lens 220 can vary according to the liquid crystal driving voltage. Therefore, the focal length of the light refracted by the switchable liquid crystal lens 220 and the image forming position (focus position) can be adjusted according to the liquid crystal driving voltage. In the optical sensor driving mode that drives the switchable liquid crystal lens 220, the light refracted by the switchable liquid crystal lens 220 can advance to the lens of the optical sensor module 400, which is positioned to avoid the light-transmitting region UDC.

[0069] When the switching element SW is turned off, there is no potential difference between the first transparent electrode 221 and the second transparent electrode 224. In this case, the liquid crystal director of the liquid crystal layer 222 is in the horizontal direction.

[0070] When the switching element SW is turned on, a reference voltage is applied to either the first transparent electrode 221 or the second transparent electrode 224, and a liquid crystal driving voltage is applied to the other. At this time, the liquid crystal molecules rotate due to the potential difference between the first transparent electrode 221 and the second transparent electrode 224, causing the direction of the electric field between the first transparent electrode 221 and the second transparent electrode 224 to be parallel to the long axis direction of the liquid crystal molecules. Simultaneously, the liquid crystal director of the liquid crystal layer 222 changes in the vertical direction.

[0071] Lens 223 can be formed of transparent organic or inorganic materials. The thickness of lens 223 decreases as the distance from the optical sensor module 400 decreases, and a lens surface is formed on the surface of lens 223.

[0072] In display mode, no electric field is applied to the switchable liquid crystal lens 220. In display mode, there is no difference in refractive index between the liquid crystal layer 222 and the lens 223. Therefore, in display mode, as... Figure 6A As shown, light from the pixels in the second pixel array region PA2 passes through the switchable liquid crystal lens 220, the second circular polarizer 210, and the light-transmitting region UDC of the first display panel (100) and proceeds to the outside.

[0073] In the optical sensor driving mode, an electric field is applied to the switchable liquid crystal lens 220. In this mode, the liquid crystal director of the liquid crystal layer 222 can be changed, allowing the refractive index of the liquid crystal layer 222 to be greater than that of the lens 223. In the optical sensor mode, as... Figure 6B As shown, linearly polarized light along the first optical axis, passing through linear polarizer 22, is converted into circularly polarized light by first circular polarizer 21, then passes through second circular polarizer 210 and becomes linearly polarized light along the second optical axis before proceeding to switchable liquid crystal lens 220. Due to the refractive index difference between liquid crystal layer 222 and lens 223, external light incident on switchable liquid crystal lens 220 proceeds to optical sensor module 400. An inverted image of an external object can be formed on optical sensor module 400. In optical sensor driving mode, optical sensor module 400 converts incident light into electrical signals.

[0074] Circular polarizers 21 and 210 are configured between the linear polarizer 22 and the switchable liquid crystal lens 220, but this disclosure is not limited thereto. n (n is a positive integer greater than or equal to 0) A λ / 2 phase retardation layer can be disposed between the linear polarizer 22 and the switchable liquid crystal lens 220. Here, λ is the wavelength of light. In display mode, a circular polarizer (or a λ / 4 phase retardation layer) can be disposed between the linear polarizer 22 and the switchable liquid crystal lens 220 to reduce the non-uniformity of the images reproduced in the first pixel array region PA1 and the second pixel array region PA2.

[0075] Figure 7 This is a cross-sectional view showing in detail the structure of the display panel and the light guide module according to the second embodiment of this disclosure.

[0076] Reference Figure 7 The first display panel 100 includes a first pixel array region PA1 with an embedded switchable liquid crystal lens 220, a linear polarizer 23, and a circular polarizer 24.

[0077] The first pixel array region PA1 includes at least a circuit layer 12, a light-emitting element layer 14, and an encapsulation layer 16, and displays most of the input image. A switchable liquid crystal lens 220 is disposed in the light-transmitting region UDC of the first display panel 100, which has no pixels.

[0078] The linear polarizer 23 can cover the display area and the light-transmitting area UDC where the first pixel array region PA1 is disposed. The linear polarizer 23 transmits linearly polarized light propagating along the second optical axis (e.g., perpendicular to the optical axis) from the incident light. The phase retardation layer of the circular polarizer 24 is disposed on the linear polarizer 23 and the first pixel array region PA1. The circular polarizer 24 can be patterned so that only a transparent portion exists in the light-transmitting area UDC, without the phase retardation layer of the circular polarizer 24. The switchable liquid crystal lens 220 can overlap with the linear polarizer 23, and the transparent portion between the switchable liquid crystal lens 220 and the linear polarizer 23 does not have a phase retardation layer.

[0079] The second display panel 300 is disposed below the first display panel 100 and at least partially overlaps with the first display panel 100. The second pixel array region PA2 overlaps with the light-transmitting region UDC to display an image in the light-transmitting region UDC. The switchable liquid crystal lens 220 is disposed in the light-transmitting region UDC on the same layer as the first pixel array region PA1.

[0080] In the display mode, no electric field is applied to the switchable liquid crystal lens 220. In this case, since there is no refractive index difference between the liquid crystal layer and the lens of the switchable liquid crystal lens 220, light from the pixels of the second pixel array region PA2 is transmitted to the light-transmitting region UDC of the first display panel 100 and proceeds to the outside.

[0081] In the optical sensor driving mode, an electric field is applied to the switchable liquid crystal lens 220. At this time, due to the refractive index difference between the liquid crystal layer and the lens of the switchable liquid crystal lens 220, the linearly polarized light passing through the second optical axis of the linear polarizer 23 is refracted in the switchable liquid crystal lens 220 and advances to the optical sensor module 400, which is arranged to avoid the light-transmitting region UDC.

[0082] Figure 8 This is a cross-sectional view showing in detail the structure of the display panel and the light guide module according to the third embodiment of this disclosure.

[0083] Reference Figure 8 The first display panel 100 includes a first pixel array region PA1 and a linear polarizer 25. A switchable liquid crystal lens 220 is embedded in the first pixel array region PA1, and the linear polarizer 25 is disposed on the switchable liquid crystal lens 220 in the light-transmitting region UDC.

[0084] The first pixel array region PA1, comprising at least a circuit layer 12, a light-emitting element layer 14, and a packaging layer 16, displays most of the input image. A switchable liquid crystal lens 220 is disposed in the light-transmitting region UDC of the first display panel 100, which has no pixels.

[0085] The phase retardation layer of the linear polarizer 25 does not cover the first pixel array region PA1 and is disposed in the light-transmitting region UDC. Therefore, the linear polarizer 25 can be patterned to be disposed only in the light-transmitting region UDC.

[0086] The second display panel 300 is disposed below the first display panel 100 and at least partially overlaps with the first display panel 100. The second pixel array region PA2 overlaps with the light-transmitting region UDC to display an image in the light-transmitting region UDC. The switchable liquid crystal lens 220 is disposed in the light-transmitting region UDC on the same layer as the first pixel array region PA1.

[0087] In the display mode, no electric field is applied to the switchable liquid crystal lens 220. In this case, since there is no refractive index difference between the liquid crystal layer and the lens of the switchable liquid crystal lens 220, light from the pixels of the second pixel array region PA2 is transmitted to the light-transmitting region UDC of the first display panel 100 and proceeds to the outside.

[0088] In the optical sensor driving mode, an electric field is applied to the switchable liquid crystal lens 220. At this time, due to the refractive index difference between the liquid crystal layer and the lens of the switchable liquid crystal lens 220, the linearly polarized light passing through the second optical axis of the linear polarizer 25 is refracted in the switchable liquid crystal lens 220 and advances to the optical sensor module 400 arranged to avoid the light-transmitting area (UDC).

[0089] Figure 9 and Figure 10 This is a cross-sectional view showing in detail the structure of the display panel and the light guide module according to the fourth embodiment of this disclosure.

[0090] Reference Figure 9 and Figure 10 The display panel 500 is manufactured to a size larger than the screen of the mobile terminal 1000, and a portion of the display panel is folded back. The second pixel array region PA2 is disposed on the rear part B of the folded-back display panel 500.

[0091] The portion of the display panel 500 containing the second pixel array region PA2 is folded behind the light guide module 200, such that the second pixel array region PA2 faces the light guide module 200. Therefore, in the display panel 500, the light guide module 200 and the second pixel array region PA2 overlap under the light-transmitting region UDC where there are no pixels.

[0092] The display panel 500 has a front portion A with a first pixel array region PA1 and a rear portion B with a second pixel array region PA2 that overlaps with the light-transmitting region UDC.

[0093] The first pixel array region PA1 and the second pixel array region PA2 include a circuit layer 12 and a light-emitting element layer 14. The light-transmitting region UDC includes a transparent portion 101 made of only transparent insulating material in the circuit layer 12 and the light-emitting element layer 14.

[0094] The first pixel array region PA1, located on the front portion A of the display panel 500, includes at least a circuit layer 12, a light-emitting element layer 14, and an encapsulation layer 16, and displays most of the image. The region C between the first pixel array region PA1 and the second pixel array region PA2 can be a blank area where pixels are not needed. Pixels may not be formed in this region C, but this disclosure is not limited thereto. The second pixel array region PA2, located on the rear portion B of the display panel 500, overlaps with the light-transmitting region UDC, and displays the image in the light-transmitting region UDC.

[0095] The light guide module 200 is positioned between the front A and rear B of the display panel 500. For example... Figure 7 and Figure 8 As shown, the switchable liquid crystal lens 220 of the light guide module 200 can be embedded in the front part A of the display panel 500, or as... Figure 9 As shown, it can be set in the space between the front A and the rear B of the display panel 500.

[0096] Because the display panel 500 is folded, when the pixels of the first pixel array region PA1 and the pixels of the second pixel array region PA2 are implemented with the same emission type, the light can be directed in opposite directions. With this in mind, the pixels of the first pixel array region PA1 can be implemented as top-emitting, while the pixels of the second pixel array region PA2 can be implemented as bottom-emitting.

[0097] To increase the efficiency of light emitted from the pixels in the second pixel array region PA2, a reflective layer 502 can be formed to reflect light incident from the pixels in the second pixel array region PA2 to the light-transmitting region UDC. The reflective layer 502 can be formed of a metal with high reflectivity in the circuit layer 12.

[0098] The optical sensor module 400 is disposed near the rear portion B of the display panel 500 to avoid the light-transmitting area UDC. The optical sensor module 400 may overlap with the first pixel array area PA1, but this disclosure is not limited thereto.

[0099] The objectives to be achieved by the present disclosure, the means to achieve those objectives, and the effects of the present disclosure have not specifically described the basic features of the claims. Therefore, the scope of the claims is not limited to the contents of this disclosure.

[0100] Although embodiments of the present disclosure have been described in more detail with reference to the accompanying drawings, the present disclosure is not limited thereto and can be implemented in many different forms without departing from the technical concept of the present disclosure. Therefore, the embodiments disclosed herein are provided for illustrative purposes only and are not intended to limit the technical concept of the present disclosure. The scope of the technical concept of the present disclosure is not limited thereto. Therefore, it should be understood that the above embodiments are illustrative in all respects and do not limit the present disclosure. The scope of protection of the present disclosure should be interpreted based on the appended claims, and all technical concepts within their equivalents should be interpreted as falling within the scope of the present disclosure.

[0101] Cross-references to related applications

[0102] This application claims priority and benefit to Korean Patent Application No. 10-2021-0172699, filed on December 6, 2021, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A display device, the display device comprising: A first display panel, the first display panel including a first pixel array area and a light-transmitting area; A second display panel is disposed below the first display panel and includes a second pixel array area that overlaps with the light-transmitting area; as well as A light guide module is disposed between the light-transmitting area of ​​the first display panel and the second pixel array area of ​​the second display panel. The light guide module includes a switchable liquid crystal lens, which comprises a liquid crystal layer and a lens. The liquid crystal layer is disposed between the light-transmitting area of ​​the first display panel and the second pixel array area of ​​the second display panel, and is subject to an electric field according to the liquid crystal driving voltage. The lens is used to refract light passing through the liquid crystal layer. When the electric field is not applied to the liquid crystal layer, the light guide module transmits light from the second pixel array region to the light-transmitting region. When the electric field is applied to the liquid crystal layer, a refractive index difference is generated between the refractive index of the liquid crystal layer and the refractive index of the lens, and the light guide module refracts external light incident through the light-transmitting region away from the second pixel array region.

2. The display device according to claim 1, wherein The first pixel array region includes a circuit layer and a light-emitting element layer, and The light-transmitting area includes a transparent portion, which is made of a transparent insulating material only in the circuit layer and the light-emitting element layer.

3. The display device according to claim 1, further comprising: An optical sensor module is disposed at a position that avoids the light-transmitting area, and external light refracted by the light guide module is incident on the optical sensor module.

4. The display device according to claim 3, wherein, The optical sensor module is coplanar with the second display panel.

5. The display device according to claim 1, wherein, The switchable liquid crystal lens also includes: A first transparent electrode and a second transparent electrode are facing each other, and the liquid crystal layer is inserted between the first transparent electrode and the second transparent electrode to form the electric field in the liquid crystal layer according to the liquid crystal driving voltage.

6. The display device according to claim 3, wherein, The thickness of the lens decreases as the distance from the optical sensor module decreases.

7. The display device according to claim 1, wherein, The first display panel further includes: At least a linear polarizer and a first circular polarizer are stacked on the light-transmitting area.

8. The display device according to claim 7, wherein, The optical guide module also includes: A second circular polarizer is disposed between the switchable liquid crystal lens and the first circular polarizer, and The first and second circular polarizers overlap with the transparent portion of the first display panel, which is inserted between the first and second circular polarizers.

9. The display device according to claim 1, wherein, The first display panel further includes: At least a linear polarizer is stacked on the light-transmitting area.

10. The display device according to claim 9, wherein, In the first display panel, the switchable liquid crystal lens overlaps with the linear polarizer, and the transparent portion between the switchable liquid crystal lens and the linear polarizer does not have a phase retardation layer.

11. A display device, the display device comprising: The display panel includes a first pixel array area, a light-transmitting area, and a second pixel array area. as well as A light guide module is disposed below the light-transmitting area. In this configuration, the portion of the display panel containing the second pixel array area is folded behind the light guide module, such that the second pixel array area faces the light guide module. The light guide module includes a switchable liquid crystal lens disposed between the light-transmitting area and the second pixel array area. The switchable liquid crystal lens comprises a liquid crystal layer and a lens. The liquid crystal layer is subjected to an electric field according to a liquid crystal driving voltage, and the lens is used to refract light passing through the liquid crystal layer. When the electric field is not applied to the liquid crystal layer, the light guide module transmits light from the second pixel array region to the light-transmitting region. When the electric field is applied to the liquid crystal layer, a refractive index difference is generated between the refractive index of the liquid crystal layer and the refractive index of the lens, and the light guide module refracts external light incident through the light-transmitting region away from the second pixel array region.

12. The display device according to claim 11, wherein, Each of the first pixel array region and the second pixel array region includes a circuit layer and a light-emitting element layer, and The light-transmitting area includes a transparent portion, which is made of a transparent insulating material only in the circuit layer and the light-emitting element layer.

13. The display device according to claim 11, further comprising: An optical sensor module is disposed at a position that avoids the light-transmitting area, and external light refracted by the light guide module is incident on the optical sensor module.

14. The display device according to claim 11, wherein, The switchable liquid crystal lens also includes: A first transparent electrode and a second transparent electrode are facing each other, and the liquid crystal layer is inserted between the first transparent electrode and the second transparent electrode to form the electric field in the liquid crystal layer according to the liquid crystal driving voltage.

15. A mobile terminal, the mobile terminal comprising: The display panel includes a first pixel array area, a light-transmitting area, and a second pixel array area. The light guide module is disposed below the light-transmitting area, wherein the portion of the display panel having the second pixel array area is folded behind the light guide module, such that the second pixel array area faces the light guide module. An optical sensor module is disposed at a location that avoids the light-transmitting area and includes one or more optical sensors, wherein external light refracted by the light guide module is incident on the one or more optical sensors; A display module, configured to write pixel data of an input image into the first pixel array region and the second pixel array region; and The host system is used to transmit photo data received from the optical sensor module to the display module. The light guide module includes a switchable liquid crystal lens disposed between the light-transmitting area and the second pixel array area. The switchable liquid crystal lens comprises a liquid crystal layer and a lens. The liquid crystal layer is subjected to an electric field according to a liquid crystal driving voltage, and the lens is used to refract light passing through the liquid crystal layer. When the electric field is not applied to the liquid crystal layer, the light guide module transmits light from the second pixel array region toward the light-transmitting region. When the electric field is applied to the liquid crystal layer, a refractive index difference is generated between the refractive index of the liquid crystal layer and the refractive index of the lens, and the light guide module refracts the external light incident through the light-transmitting region toward the optical sensor module.

16. The mobile terminal according to claim 15, wherein, The switchable liquid crystal lens also includes: A first transparent electrode and a second transparent electrode are facing each other, and the liquid crystal layer is inserted between the first transparent electrode and the second transparent electrode to form the electric field in the liquid crystal layer according to the liquid crystal driving voltage.

17. The mobile terminal according to claim 15, wherein, The host system processes user facial authentication based on data received from the optical sensor module.

18. A display device, the display device comprising: A first display panel, comprising a first pixel array region and a light-transmitting region, wherein a switchable liquid crystal lens overlapping the light-transmitting region is embedded in the first pixel array region; and A second display panel is disposed below the first display panel and includes a second pixel array region overlapping the light-transmitting area. The switchable liquid crystal lens includes a liquid crystal layer and a lens. The liquid crystal layer is subjected to an electric field according to a liquid crystal driving voltage, and the lens is used to refract light passing through the liquid crystal layer. When the electric field is not applied to the liquid crystal layer, the switchable liquid crystal lens transmits light from the second pixel array region to the light-transmitting region. When the electric field is applied to the liquid crystal layer, a refractive index difference is generated between the refractive index of the liquid crystal layer and the refractive index of the lens. The switchable liquid crystal lens refracts external light incident through the light-transmitting region away from the second pixel array region.

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