TW202212939A - Display device and operating method thereof - Google Patents

Abstract

A display device and an operating method thereof are provided and used for detecting a fingerprint of a finger. The display device has a display region. The display device includes a liquid crystal display panel, a light source, a local adjusting structure, and a plurality of photo sensors. The light source is disposed under the liquid crystal display panel. The local adjusting structure is disposed between the light source and the liquid crystal display panel and includes a first electrode layer, a liquid crystal layer, and a second electrode layer. The photo sensors are disposed in the display region of the liquid crystal display panel.

Description

Display device and method of operating the same

The present invention relates to a display device and an operation method thereof, in particular to a display device with a fingerprint identification function and an operation method thereof.

With the rapid advancement of technology, portable display devices, such as smart phones, tablet PCs, or laptop PCs, have become essential tools in people's lives. As its functions become more and more diverse, it usually stores private information, such as phonebooks, photos or personal identification information, with a certain degree of privacy. In order to protect these data, fingerprint identification devices have been developed for use in portable display devices. However, the traditional fingerprint identification device does not have light transmittance, thus limiting the screen ratio of the display device. To this end, the industry has developed an under-screen fingerprint sensor, such as an optical fingerprint sensor, which enables it to detect fingerprint images without affecting the screen ratio. At present, the mainstream display device with optical fingerprint sensor is an organic light emitting diode display device. The organic light emitting diode display device itself is used as a light source to generate detection light to illuminate the finger, so that the optical fingerprint sensor can detect Acquires fingerprint images from light reflected from the finger. However, after the light is reflected by the finger, it will diverge into complex reflected light, which causes the optical fingerprint sensor to receive the reflected light corresponding to the fingerprints at different positions of the finger, which makes the image detected by the fingerprint identification device unsatisfactory, which in turn affects the result of fingerprint identification. . Therefore, a collimator is usually provided on the fingerprint sensor to filter out the reflected light with a large incident angle. However, if the collimator is used in the liquid crystal display device, the brightness of the display device will be greatly reduced, and the image cannot be displayed normally. Therefore, the combination of setting the collimator on the fingerprint sensor can only be applied to the expensive organic light emitting diodes In the volume display device, the cost of the overall display device cannot be further reduced.

Another embodiment of the present invention provides a display device for detecting a fingerprint of a finger, and the display device has a display area. The display device includes a liquid crystal display panel, a light source, a local adjustment structure and a plurality of light sensors. The light source is arranged under the liquid crystal display panel. The local adjustment structure is arranged between the light source and the liquid crystal display panel, and the local adjustment structure includes a first electrode layer, a liquid crystal layer and a second electrode layer, wherein when the display device performs fingerprint identification, the display area where the finger approaches or touches is A fingerprint identification area, and the haze of the part of the local adjustment structure located in the fingerprint identification area is smaller than the haze of another part of the local adjustment structure located outside the fingerprint identification area. The light sensor is arranged in the display area of the liquid crystal display panel.

Yet another embodiment of the present invention provides an operating method of a display device. The display device includes a light source, a liquid crystal panel disposed on the light source, and a plurality of light sensors. The liquid crystal panel has a display area, and the light sensor is arranged in the display area. First, enter a fingerprint identification mode. When a finger approaches or touches the display area of the display device, the display area where the finger approaches or touches is determined as a fingerprint identification area, and a fingerprint identification step is performed, wherein the fingerprint identification step includes adjusting the liquid crystal panel in the fingerprint identification area. liquid crystal molecules, so that at least a part of the liquid crystal panel located in the fingerprint identification area is in a light-transmitting state, and the light generated by the light source is allowed to pass through at least a part of the liquid crystal panel and be directed to the finger, wherein the finger reflects the light into a reflected light; and use the light The sensor detects the reflected light reflected from the finger to obtain a fingerprint image of the finger. Then, it is determined whether the fingerprint image corresponds to a fingerprint information.

Those skilled in the art can understand the present invention by referring to the following detailed description in conjunction with the accompanying drawings. It should be noted that, in order to facilitate the reader's understanding and to make the drawings concise, the drawings of the present invention only depict A portion of a device is shown, and certain elements in the accompanying drawings are not drawn to scale. In addition, the number and size of each element in the figures are for illustration only, and are not intended to limit the scope of the present invention.

The ordinal numbers such as "first", "second", etc. used in the description and the claimed items are used to modify the elements of the claimed items. They do not imply and represent that the claimed elements have any previous ordinal numbers, nor do they represent The order of a request element and another request element, or the order of the manufacturing method, the use of these ordinal numbers is only used to make a request element with a certain name and another request element with the same name can be clearly distinguished .

It should be noted that the technical solutions provided by the different embodiments hereinafter can be replaced, combined or used in combination, so as to constitute another embodiment without violating the spirit of the present disclosure.

The display device provided by the present invention generates relatively collimated detection light through a part of it, which is used to detect the image of the fingerprint, so that the reflected light from the finger can also be more collimated, so the light of the display device in the display area The sensor can detect a clear image of a fingerprint, so that it can detect fingerprints without affecting the screen ratio.

Please refer to FIGS. 1 to 3. FIG. 1 is a schematic top view of a display device according to a first embodiment of the present invention, and FIG. 2 is a top view of a display device with a first electrode corresponding to the first embodiment of the present invention. , FIG. 3 is a schematic cross-sectional view along the section line AA' of FIG. 2 . For clear illustration, FIG. 2 only illustrates the top-view relationship between the first electrode and the color filter layer. As shown in FIG. 1 , the display device 11 provided in this embodiment has a display area DR for displaying images, and the display area DR has a fingerprint identification area FR for detecting the fingerprint of the finger F. As shown in FIG. For example, the fingerprint recognition area FR may be an area that can be completely covered by the finger F, that is, the area where the fingerprint recognition of the finger F will be performed within a certain period of time. In this embodiment, the finger F can be singular or plural. In this embodiment, the fingerprint recognition area FR is not a specific area in the display area DR, but is any area in the display area DR where the finger F approaches or touches. That is to say, the display device 11 of the present embodiment is a display device for fingerprint on display (FOD), and the fingerprint of the finger F can be detected in any area of the display area DR, that is, any area of the display area DR can detect the fingerprint of the finger F. All areas are latent fingerprint identification areas. In other embodiments, the fingerprint recognition area FR is limited to a part of the display area DR, that is, the latent fingerprint recognition area is limited to a part of the display area DR. The display device 11 of the present embodiment may also have a non-display area NDR, which is located on at least one side of the display area DR, for example, may surround the display area DR, but is not limited thereto, wherein the non-display area NDR may be used, for example, for arranging peripheral components or Opaque element. In some embodiments, since the fingerprint recognition area FR is located in the display area DR, the display device 11 may also not have the non-display area NDR, that is, the display device 11 may have the feature of having no frame. Herein, "proximity" refers to the distance at which the display device 11 can detect the fingerprint of the finger F when the finger F has not yet touched the display device 11 . For example, the distance at which the display device 11 can detect the fingerprint of the finger F may be smaller than the width of the finger F, but is not limited thereto.

As shown in FIGS. 1 to 3 , the display device 11 includes a light source 102 , a liquid crystal panel 104 and a plurality of light sensors 106 . The light source 102 can be used to generate light L1, and the liquid crystal panel 104 is disposed on the light source 102 to control whether the light L1 is allowed to penetrate, so that the light L2 emitted from the light emitting surface 104S of the liquid crystal panel 104 can be used for displaying or detecting fingerprints . The liquid crystal panel 104 includes a first electrode layer 108, a liquid crystal layer 110 and a second electrode layer 112, wherein the liquid crystal layer 110 is disposed between the first electrode layer 108 and the second electrode layer 112, and includes liquid crystal molecules 110L, and The amount of light L1 passing through the liquid crystal panel 104 can be adjusted by controlling the deflection direction of the liquid crystal molecules 110L. The first electrode layer 108 includes at least one first electrode 108E1 disposed in the fingerprint identification region FR, and the first electrode 108E1 has a plurality of openings OP for allowing light L1 to pass through during fingerprint detection. In this embodiment, the first electrode layer 108 may include a plurality of first electrodes 108E1 with openings OP, which are insulated from each other and disposed in the display region DR. Each light sensor 106 may correspond to one of the openings OP. When the display device 11 is performing fingerprint identification, by providing a voltage difference between the first electrode 108E1 and the second electrode layer 112 or between the first electrode 108E1 and the third electrode layer 114, the liquid crystal molecules 110L corresponding to the first electrode 108E1 can be rotated In the dark state (that is, the light L1 cannot pass through the liquid crystal panel 104), for example, it rotates to a vertical alignment, and the liquid crystal molecules 110L corresponding to the opening OP will not rotate to the dark state (that is, the light L1 can pass through the liquid crystal panel 104), for example, it is still horizontally aligned. Therefore, the light L1 generated by the light source 102 can only penetrate through the liquid crystal panel 104 corresponding to the opening OP, thereby collimating the light L2 emitted from the light emitting surface 104S of the liquid crystal panel 104 . In this way, the reflected light L3 corresponding to different fingerprint positions received by the light sensor 106 can be reduced, so as to improve the detected image quality and improve the accuracy of fingerprint identification.

Specifically, as shown in FIG. 3 , the liquid crystal panel 104 of the present embodiment may be, for example, a liquid crystal display panel, so the light source 102 may include, for example, a backlight module for generating flat light L1 . The backlight module can be, for example, an edge type or a direct type. When the backlight module is a direct type, the backlight module may include, for example, a plurality of light emitting diodes arranged below the liquid crystal panel 104, but the invention is not limited thereto. In addition, the liquid crystal panel 104 of this embodiment may further include a third electrode layer 114 and an insulating layer 116 , the second electrode layer 112 is disposed between the liquid crystal layer 110 and the third electrode layer 114 , and the insulating layer 116 is disposed on the third electrode layer 114 . Between the second electrode layer 112 and the third electrode layer 114 , the second electrode layer 112 and the third electrode layer 114 are electrically insulated. The second electrode layer 112 includes a plurality of second electrodes 112E, and each of the second electrodes 112E may have at least one slit SL. Providing a voltage difference between 112E and the third electrode layer 114 can generate a horizontal electric field in the liquid crystal layer 110 , thereby controlling the deflection of the liquid crystal molecules 110L in the liquid crystal layer 110 , so that the display device 11 can display an image. In other words, the liquid crystal display panel of this embodiment may be of fringe field switching type, for example. For example, the second electrode 112E can be used as a pixel electrode, and the third electrode layer 114 can be used as a common electrode, but the invention is not limited thereto. In some embodiments, the third electrode layer 114 may also include a plurality of electrodes, respectively corresponding to one second electrode 112E. In this case, one of the second electrode 112E and the electrode may be a pixel electrode, and the other may be a pixel electrode. common electrode. In some embodiments, the second electrode layer 112 may also include a second electrode 112E with a slit SL and an electrode with a slit, and the slit SL of the second electrode 112E and the slit of the electrode are in a plan view direction TD staggered from each other, that is, the liquid crystal display panel may be of in-plane switching type. In some embodiments, the liquid crystal display panel may also be of other types, such as a vertical aligned (VA) type or a multi-domain vertically aligned (MVA) type.

In addition to the first electrode layer 108 , the liquid crystal layer 110 , the second electrode layer 112 , the third electrode layer 114 and the insulating layer 116 , the liquid crystal panel 104 of this embodiment may further include a first substrate 118 , a thin film transistor layer 120 , The color filter layer 122 , the black matrix layer 124 and the second substrate 126 . The first substrate 118 and the second substrate 126 are disposed opposite to each other, and the liquid crystal layer 110 is disposed between the first substrate 118 and the second substrate 126 . In this embodiment, the thin film transistor layer 120 , the third electrode layer 114 , the insulating layer 116 and the second electrode layer 112 can be sequentially formed on the first substrate 118 , and each second electrode 112E can be electrically connected to the thin film Corresponding thin film transistors in the transistor layer 120 (not shown). In some embodiments, when the third electrode layer 114 includes electrodes, the electrodes may be electrically connected to corresponding lines (eg, common lines), but not limited thereto. Since the elements included in the thin film transistor layer 120 , such as thin film transistors, storage capacitors, data lines or scan lines, and their electrical connection methods are well known to those skilled in the art, and there may be various types of changes, here Not much to say.

In addition, in this embodiment, the color filter layer 122 can be disposed between the second substrate 126 and the liquid crystal layer 110, the black matrix layer 124 can also be disposed between the second substrate 126 and the liquid crystal layer 110, and the first electrode Layer 108 may be located between color filter layer 122 and liquid crystal layer 110 and between black matrix layer 124 and liquid crystal layer 110 . For example, the color filter layer 122 , the black matrix layer 124 and the first electrode layer 108 may be sequentially formed on the second substrate 126 , but not limited thereto. In some embodiments, the black matrix layer 124 may also be disposed between the color filter layer 122 and the second substrate 126 , or the color filter layer 122 may be formed in the opening 124 a of the black matrix layer 124 . Further, the color filter layer 122 of this embodiment may include a plurality of first color filters 122a, a plurality of second color filters 122b and a plurality of third color filters 122c, which are disposed on the first electrodes on layer 108. The first color filter 122a, the second color filter 122b and the third color filter 122c may have different colors, respectively, so that the first color filter 122a, the second color filter 122b and the third color filter The light from the color filter 122c can be mixed to produce white light. For example, a first color filter 122a, a second color filter 122b and a third color filter 122c arranged side by side may correspond to the same pixel of the liquid crystal display panel. In addition, the first color filter 122a may be, for example, a red filter, the second color filter 122b may be, for example, a green filter, and the third color filter 122c may be, for example, a blue filter, but not limited to this.

Please continue to refer to FIG. 2 , in this embodiment, each opening OP of the first electrode 108E1 may correspond to the first color filter 122 a , the second color filter 122 b or the third color filter respectively in the plan view direction TD One of the sheets 122c, so that the light L2 used to detect the fingerprint can have the same color. The size of the opening OP may be smaller than that of the corresponding color filter, but is not limited thereto. For example, since red light is easily absorbed by the human body and blue light is easy to affect the light sensor 106, the opening OP of the first electrode 108E1 may correspond to a green filter, but not limited thereto. In some embodiments, each opening OP of the first electrode 108E1 may also correspond to or overlap with the first color filter 122a, the second color filter 122b and the third color filter of the same pixel in the top view direction TD. At least two of the sheets 122c. In addition, the first electrode 108E1 of this embodiment may overlap with a plurality of first color filters 122a, a plurality of second color filters 122b, and a plurality of third color filters 122c in the plan view direction TD, but does not limited to this. In addition, the black matrix layer 124 may have a plurality of openings 124a, each corresponding to a sub-pixel. For example, the first color filter 122a, the second color filter 122b, and the third color filter 122c may respectively correspond to one opening 124a, as shown in FIG. 3, in other words, the first color filter 122a , The second color filter 122b and the third color filter 122c can respectively cover the corresponding openings 124a.

As shown in FIG. 3 , each photo sensor 106 may correspond to an opening OP of the first electrode 108E1 , for example, in the top view direction TD of the display device 11 , each photo sensor 106 is disposed or disposed adjacent to the corresponding opening OP in the corresponding opening OP. In this embodiment, each photo sensor 106 may be disposed in one opening 124a of the black matrix layer 124, respectively. For example, the light sensor 106 may be disposed in the opening 124a corresponding to the second color filter 122b, and between the second color filter 122b and the first electrode 108E1, but not limited thereto. The position of the light sensor 106 can be determined according to the color of the light to be received. In some embodiments, the light sensor 106 may also be disposed on any layer (horizontal plane) between the black matrix layer 124 and the second substrate 126 , such as the same layer as the black matrix layer 124 , or disposed on the thin film transistor layer 120 . middle. The light sensor 106 may be, for example, a photodiode or a phototransistor, but is not limited thereto.

In this embodiment, the liquid crystal panel 104 may further include an adhesive layer 128 , an upper polarizer 130 and a lower polarizer (not shown), wherein the upper polarizer 130 can be attached to the upper surface of the second substrate 126 through the adhesive layer 128 The upper and lower polarizers can be attached to the lower surface of the first substrate 118 through another adhesive layer (not shown). In order to clearly show the display device 11 , the lower polarizer and the adhesive layer are omitted in FIG. 3 , but the present invention is not limited thereto. Through the polarization directions of the upper polarizer 130 and the lower polarizer and the alignment direction of the liquid crystal molecules 110L, the liquid crystal panel 104 can achieve a bright state and a dark state. The polarization directions of the upper polarizer 130 and the lower polarizer can be adjusted according to actual needs. In addition, the display device 11 may further include an adhesive layer 132 and a cover plate 134 , wherein the cover plate 134 is attached to the polarizer 130 through the adhesive layer 132 . In some embodiments, the liquid crystal panel 104 may further include a spacer SP disposed in the liquid crystal layer 110 to maintain the thickness of the liquid crystal layer 110 .

Please continue to refer to Figures 1 and 2. The first electrodes 108E1 in this embodiment can be distributed in the entire display area DR, so a part of the first electrodes 108E1 are disposed in the display area DR outside the latent fingerprint identification area that can be used as the fingerprint identification area FR. For example, the first electrode 108E1 can form a touch element, so that the first electrode 108E1 can detect the position when a finger approaches or touches the display device 11 . In this embodiment, the first electrodes 108E1 can be arranged in a matrix and are electrically connected to the touch control elements through wires insulated from each other. In other words, the first electrodes 108E1 in this embodiment can form a self-capacitance touch element, but Not limited to this. Since each of the first electrodes 108E1 in this embodiment is used as a touch electrode, it may overlap with a plurality of second electrodes 112E as pixel electrodes in the plan view direction TD, but is not limited thereto. The overlapping quantity of the second electrode 112E and the single first electrode 108E1 can be adjusted according to the display resolution and touch resolution required by the display device 11 .

The driving method of the display device of this embodiment will be further described below. Please refer to FIG. 4 and FIG. 5, and refer to FIG. 1 and FIG. 3 together. FIG. 4 illustrates the synchronization signal, the driving signal of the third electrode, and the first electrode of the liquid crystal panel according to the first embodiment of the present invention. The timing chart of the driving signal of FIG. 5 is a schematic diagram of displaying an image by the display device according to the first embodiment of the present invention. As shown in FIG. 4 and FIG. 5, the signal provided by the display device 11 to the liquid crystal panel 104 is the synchronization signal S1, which is provided to the area located in the fingerprint identification area FR (for example, at least a part of the area covered by the finger F) The signal of the first electrode 108E1 is the driving signal S2, and the signal provided to the first electrode 108E1 outside the area determined as the fingerprint identification region FR is the driving signal S3. In this embodiment, the synchronization signal S1 may be, for example, a synchronization signal in the vertical direction of the display screen, namely a vertical synchronization signal (Display V-Sync), which is provided to the liquid crystal panel 104 to indicate a frame time (Frame), and is provided synchronously. to scan lines and data lines. In each picture period T1, T2, the display device 11 displays a corresponding picture, wherein the picture period T1, T2 may have a display driving period DT1, DT2 and an interval period BT1, BT2, respectively, and the interval period BT1, BT2 may be, for example, A vertical blank period. In the display driving period DT1, the synchronization signal S1 provided to the liquid crystal panel 104 may be at a high level, the driving signal S2 provided to the first electrode 108E1 in the fingerprint identification area FR and the first electrode 108E1 outside the fingerprint identification area FR The driving signals S3 are all at low level, so the liquid crystal molecules 110L can exhibit horizontal alignment, so that the light L2 emitted from the light emitting surface 104S of the liquid crystal panel 104 can present an image. During the interval period BT1, the synchronization signal S1 provided by the display device 11 is at a low level, and the display signal Sx is at a high level, so that the liquid crystal panel 104 continues to display the same image during the interval period BT1. At the same time, in the interval period BT1, the driving signal S2 provided to the first electrode 108E1 in the fingerprint identification region FR and the driving signal S3 provided to the first electrode 108E1 outside the fingerprint identification region FR can both be at a high level, so that the first electrode 108E1 is at a high level. An electrode 108E1 can detect whether a finger touches the display device 11 . The display signal Sx can be, for example, a data enable (DE) signal.

Next, as shown in FIG. 3 and FIG. 4 , in the display driving period DT2 when the screen period T2 for displaying the next screen is entered, when the display device 11 wants to perform fingerprint recognition, the driving signal S2 is provided to the first electrode 108E1 It can be maintained at the high level until the image of the fingerprint is detected, and then it drops to the low level, that is, the fingerprint detection is stopped. Since the user cannot view the image of the fingerprint recognition area FR when the finger F touches the fingerprint recognition area FR of the display device 11 (eg, at least a part of the area covered by the finger F), the driving signal S2 is maintained at a high level during the display driving period DT2 Bits do not affect the image the user sees. When the driving signal S2 is maintained at a high level, a voltage difference will be generated between the first electrode 108E1 and the second electrode 112E located therebelow and/or the first electrode 108E1 and the third electrode layer 114, so that the liquid crystal molecules 110L are deflected to dark state. For example, the long axes of the liquid crystal molecules 110L may be rotated to a vertical alignment, eg, parallel to the top-view direction TD. Since the first electrode 108E1 has the opening OP, the liquid crystal molecules 110L corresponding to the opening OP will not be deflected to a dark state, for example, still in a horizontal alignment, so the light L1 from the light source 102 can penetrate the display device 11 corresponding to the opening OP to serve as a The detection light (eg, light L2 ), and the traveling direction of the detection light can be close to the normal direction of the display surface 1a of the display device 11 (eg, the top view direction TD), thereby improving the collimation of the detection light. In this way, the mutual interference of the reflected light L3 after the detection light passing through the adjacent openings OP is reflected by the finger can be reduced, so as to improve the image definition detected by the light sensor 106 .

Furthermore, as shown in FIGS. 1 and 4, the driving signal S3 provided to the first electrode 108E1 located outside the fingerprint identification area FR is at a low level during the display driving period DT2, so the display located outside the fingerprint identification area FR is at a low level. Area DR can still display the picture normally. That is to say, the display area DR other than the area covered with the finger F and the fingerprint recognition of the finger F will be performed within a certain period of time can still display images normally. In addition, when the display device 11 does not perform fingerprint recognition, the driving signal S2 provided to the first electrode 108E1 is at a low level during other driving periods (eg, the display driving period DT3 ), so that the fingerprint recognition area FR of the display device 11 can be An image is displayed, as shown in FIG. 5 , so the entire display area DR of the display device 11 can display a complete image.

As can be seen from the above, the display device 11 of the present embodiment not only uses the liquid crystal panel 104 as a device for displaying images, but also enables the light sensor 106 of the display device 11 to detect the light passing through the liquid crystal panel 104 by collimating the detection light. A clear fingerprint image is detected, so the display device 11 can have a fingerprint identification function. Thereby, the overall cost of the display device 11 can be effectively reduced.

The display device of the present invention is not limited to the above-mentioned embodiments. In order to facilitate the comparison of the differences between the first embodiment and other embodiments and simplify the description, the same symbols are used to denote the same elements in other embodiments below, and mainly focus on the differences between the first embodiment and the other embodiments. The differences will be explained, and repeated parts will not be repeated.

Please refer to FIG. 6 , which is a schematic top view of a display device according to a variation of the first embodiment of the present invention. As shown in FIG. 6 , the difference between this modified embodiment and the above-mentioned embodiment is that a part of the first electrode 108E1 of the display device 12 can be replaced with a third electrode 108E2 without an opening, and the third electrode 108E2 is disposed in the display area DR . Since the third electrode 108E2 does not have an opening, the portion of the display device 12 corresponding to the third electrode 108E2 cannot perform fingerprint recognition. In other words, the display region DR corresponding to the third electrode 108E2 does not have a fingerprint recognition function. In this variant embodiment, the distribution range of the third electrode 108E2 may be determined according to the disposition area of the first electrode 108E1 . For example, the distribution range of the first electrode 108E1 is a latent fingerprint recognition area that can be used as the fingerprint recognition area FR, and the third electrode 108E2 is disposed outside the latent fingerprint recognition area, but not limited thereto. The third electrode 108E2 may be formed of, for example, the first electrode layer 108 . In the top view direction TD, the first color filter 122a, the second color filter 122b and the third color filter 122c may, for example, completely overlap the third electrode 108E2. The outline size of the third electrode 108E2 may be, for example, the same as that of the first electrode 108E1, but is not limited thereto. In the driving method of the display device 12 of the present variant embodiment, the third electrode 108E2 provides the driving signal S3. Since the first electrode 108E1 and the driving signal provided in this variant embodiment are the same as those in the above-mentioned embodiment, they will not be repeated here.

Please refer to FIG. 7 , which is a schematic diagram of a method for fingerprint recognition by a display device according to a second embodiment of the present invention. As shown in FIG. 7 , the display device 2 provided in this embodiment may include a liquid crystal display panel 204 and a light source 102 . The liquid crystal display panel 204 of this embodiment can be any type of liquid crystal display panel, such as a vertical alignment type or a lateral electric field switching type liquid crystal display panel, but not limited thereto. For example, the liquid crystal display panel 204 may include a color filter substrate 2041, a thin film transistor substrate 2042, a liquid crystal layer 110, an upper polarizer 230 and a lower polarizer 216, and the liquid crystal layer 110 is disposed on the color filter substrate 2041 and the thin film Between the transistor substrates 2042 , the upper polarizer 230 and the lower polarizer 216 are respectively disposed on the light exit surface 204S1 and the light entrance surface 204S2 of the liquid crystal display panel 204 . Also, the liquid crystal display panel 204 may include a plurality of pixels PX1, PX2, and each pixel PX1, PX2 may, for example, include sub-pixels SPX1, SPX2, SPX3, respectively. In the present invention, the number of sub-pixels SPX1 , SPX2 and SPX3 in each pixel PX1 and PX2 is not limited to this. In the present embodiment, when the display device 2 performs fingerprint recognition, a part of the non-adjacent pixels PX1 in the fingerprint recognition area FR can be turned on, and another part of the non-adjacent pixels PX2 can be turned off, so that the fingerprint recognition area FR is closed. The liquid crystal layer 110 of the pixels PX1 and PX2 may form a grating 110G. In other words, the turned-on pixels PX1 and the turned-off pixels PX2 are alternately arranged in sequence. In this way, the divergence angle θ of the light penetrating the liquid crystal display panel 204 can be reduced through the size of the openings 110a of the grating 110G and the spacing between the openings 110a, thereby reducing the incident angle of the reflected light entering the light sensor, thereby effectively improving the Detects the collimation of light. The width of the turn-on pixel PX1 and the width of the turn-off pixel PX2 may be, for example, 60 μm, respectively, but not limited thereto. For example, the number of pixels PX1 between adjacent and off pixels PX2 may be one, and the number of pixels PX2 between adjacent and on pixels PX1 may be one, so for a single point light source, the point The divergence angle θ of the light generated by the light source may be less than 11 degrees, but is not limited thereto. The divergence angle θ of the light, the width of the open pixel PX1 and the width of the closed pixel PX2 can be adjusted by changing the number of pixels PX1 between adjacent and closed pixels PX2 and the number of pixels PX2 between adjacent and open pixels PX1 . In some embodiments, the display device 2 may optionally further include a touch element and a cover plate disposed on the liquid crystal display panel 204 .

Please refer to FIG. 8 , which is a schematic diagram of a method for fingerprint identification performed by a display device according to a variation of the second embodiment of the present invention. As shown in FIG. 8 , the difference between this variant embodiment and the above-mentioned embodiment is that the display device 2 provided by this variant embodiment only turns on non-adjacent sub-pixels SPX2 in the fingerprint identification area FR when performing fingerprint identification. , and turn off other sub-pixels SPX1 and SPX3 to form a grating 110G. Since only the width W of a single sub-pixel SPX2 allows light to pass through in this variant embodiment, the width of the opening 110a of the grating 110G can be reduced to reduce the divergence angle of the light passing through the liquid crystal display panel 204. For example, a single-point light source is used. In other words, the divergence angle θ of the light generated by the point light source can be reduced to less than 4 degrees. Thereby, the collimation of the detection light can be effectively improved. In this variant embodiment, the turned-on sub-pixels SPX2 can be, for example, all sub-pixels that generate the same color, such as green sub-pixels. In addition, there may be at least two off sub-pixels between adjacent green sub-pixels SPX2 that are turned on, such as sub-pixels SPX1 and SPX3. In this variant embodiment, when fingerprint identification is performed, the green sub-pixel SPX2 that is turned on is not the adjacent green sub-pixel SPX2, but a green sub-pixel SPX2 that is turned off is disposed therebetween, and other red sub-pixels SPX1 or The blue sub-pixel SPX3 may be turned off, but not limited thereto. In some embodiments, as the distance between the two adjacent sub-pixels SPX2 that are turned on is larger (or the number of sub-pixels is larger), the mutual interference of the detection lights emitted from the two adjacent sub-pixels SPX2 can be reduced, to improve the detected image quality. For example, there may be at least four sub-pixels between two adjacent sub-pixels SPX2 that are turned on.

Please refer to FIG. 9 , which is a schematic cross-sectional view of a display device according to a third embodiment of the present invention. As shown in FIG. 9 , the difference between the display device 31 provided in this embodiment and the display device 11 shown in FIG. 3 is that the liquid crystal panel 304 of the display device 31 is used for collimating detection light, and another It includes a liquid crystal display panel 340 disposed between the light source 102 and the liquid crystal panel 304 for displaying images. Specifically, the liquid crystal panel 304 of this embodiment may only include the second substrate 126 , the first electrode layer 308 , the liquid crystal layer 110 , the second electrode layer 312 and the first substrate 118 , but not include the thin film transistor layer, the third Electrode layer, color filter layer and black matrix layer. The first electrode layer 308 may include at least one first electrode 308E1, and the first electrode 308E1 of this embodiment may have a similar or the same pattern as the first electrode of the first embodiment, and thus may have a plurality of openings OP. The first electrode 308E1 can overlap the second electrode layer 312 in the top view direction TD, and the bright state and the dark state of the liquid crystal panel 304 can be adjusted through the voltage difference between the first electrode 308E1 and the second electrode layer 312 . Since the first electrode 308E1 has the opening OP, when the display device 31 performs fingerprint identification, the part of the liquid crystal panel 304 corresponding to the first electrode 308E1 can be in a dark state, and the part corresponding to the opening OP can be in a bright state, so that the detection light (eg light L2) can be collimated. In this embodiment, the liquid crystal panel 304 may further include an upper polarizer 330U and a lower polarizer 330L, which are respectively attached to the upper surface of the second substrate 126 and the lower surface of the first substrate 118 through the adhesive layers AL1 and AL2. In addition, the liquid crystal panel 304 can be pasted on the light emitting surface 340S of the liquid crystal display panel 340 through the adhesive layer AL3. In some embodiments, the first electrodes 308E1 can be distributed in the entire display area, so that the first electrodes 308E1 can form a touch element for detecting the position of a finger, but not limited thereto. In some embodiments, the first electrode layer 308 may optionally further include a plurality of third electrodes (not shown), and the first electrodes 308E1 and the third electrodes may form a touch element for detecting the position of a finger. In some embodiments, the display device 31 may further include a touch panel disposed on the liquid crystal panel 304 .

The liquid crystal display panel 340 of this embodiment can be any type of liquid crystal display panel, and the fringe electric field switching type is used as an example below, but is not limited thereto. The difference between the liquid crystal display panel 340 of this embodiment and the liquid crystal panel 104 shown in FIG. 3 is that the liquid crystal display panel 340 does not include the first electrode layer, and therefore does not have the touch sensing function and the fingerprint identification function. For example, the liquid crystal display panel 340 may include a third substrate 342, a fourth substrate 344, another liquid crystal layer 346, a thin film transistor layer 348, a third electrode layer 350, an insulating layer 352, a fourth electrode layer 354, a color filter Optical layer 122 and black matrix layer 124 . The third substrate 342 , the fourth substrate 344 , the other liquid crystal layer 346 , the thin film transistor layer 348 , the third electrode layer 350 , the insulating layer 352 , the fourth electrode layer 354 , the color filter layer 122 and the black matrix in this embodiment The layers 124 can be respectively similar to or the same as the first substrate, the second substrate, the liquid crystal layer, the thin film transistor layer, the third electrode layer, the insulating layer, the second electrode layer, the color filter layer, and the black matrix layer of the first embodiment. , so I won't go into details here. Although not shown in FIG. 9 , the liquid crystal display panel 340 may further include a lower polarizer disposed between the third substrate 342 and the light source 102 . The liquid crystal display panel 340 of this embodiment can share the lower polarizer 330L with the liquid crystal panel 304 , and it is not necessary to additionally provide another upper polarizer, but it is not limited thereto.

In addition, in this embodiment, each opening OP of the first electrode 308E1 may correspond to one of the first color filter 122a, the second color filter 122b or the third color filter 122c respectively in the plan view direction TD For example, each opening OP can expose a corresponding second color filter 122b in the top view direction TD, so that the light L2 emitted from the liquid crystal display panel 340 can pass through the part of the liquid crystal panel 304 corresponding to the opening OP to serve as the detection light . The photo sensor 306 of this embodiment may be disposed in the liquid crystal display panel 340, for example, in the opening 124a of the black matrix layer 124 corresponding to the opening OP of the first electrode 308E1, but not limited thereto. In some embodiments, the light sensor 306 may also be disposed in the thin film transistor layer 348 corresponding to the opening OP of the first electrode 308E. In some embodiments, the light sensor 306 may also be disposed in the liquid crystal panel 304 .

Please refer to FIG. 10, which is a schematic cross-sectional view of a display device according to a variation of the third embodiment of the present invention. As shown in FIG. 10 , the display device 32 provided in this embodiment differs from the display device 31 shown in FIG. 9 in that the display device 32 replaces the liquid crystal display panel and the backlight module with a self-luminous display panel 356 . Specifically, the light source 102 includes a self-luminous display panel 356 , such as an organic light-emitting diode display panel, disposed below the liquid crystal panel 304 , that is, the liquid crystal panel 304 is disposed between the self-luminous display panel 356 and the cover plate 134 . In this embodiment, the self-luminous display panel 356 may include a plurality of first light-emitting elements 358a, a plurality of second light-emitting elements 358b, and a plurality of third light-emitting elements 358c disposed on the third substrate 342 for displaying images. The first light-emitting element 358a, the second light-emitting element 358b and the third light-emitting element 358c can respectively generate light of different colors to mix white light. For example, the first light-emitting element 358a can generate blue light, and the second light-emitting element 358b can generate light of different colors. For green light, the third light emitting element 358c can generate red light, but is not limited thereto. The first light emitting element 358a, the second light emitting element 358b and the third light emitting element 358c may include organic light emitting diodes or inorganic light emitting diodes. In the present embodiment, the openings OP of the first electrode 308E1 respectively correspond to or overlap with one of the first light-emitting element 358a, the second light-emitting element 358b or the third light-emitting element 358c in the plan view direction TD, for example, may correspond or overlap One of the second light-emitting elements 358b for generating green light.

In addition, the self-luminous display panel 356 may include a plurality of thin film transistors (TFTs), which are electrically connected to the first light-emitting element 358a, the second light-emitting element 358b and the third light-emitting element 358c, respectively, and the light sensor 306 may be disposed in the self-luminous display panel 356. The light sensor 306 and the light emitting element may be formed on the same third substrate 342 . For clear illustration, the thin film transistor TFT, the light emitting element and the light sensor 306 in FIG. 10 are represented by a single block, and the thin film transistor layer is omitted, but the invention is not limited to this, the thin film transistor, the light emitting element and the light The sensors can also be formed in the same thin film transistor layer. In some embodiments, the light sensor 306 may also be disposed on the lower surface of the third substrate 342 . In addition, the self-luminous display panel 356 may further include an encapsulation cover plate 360 covering the thin film transistor TFT, the light sensor 306 and the light emitting element. In some embodiments, the package cover 360 may be replaced by an encapsulation layer.

Please refer to FIG. 11 , which is a schematic cross-sectional view of a display device according to a fourth embodiment of the present invention. As shown in FIG. 11 , the difference between the display device 4 provided in this embodiment and the above-mentioned third embodiment is that the liquid crystal panel 404 can be disposed between the liquid crystal display panel 440 and the light source 402 . Since the liquid crystal panel 404 of the present embodiment can be the same as the liquid crystal panel 304 of the third embodiment, details are not described here. In this embodiment, the liquid crystal display panel 440 may have a display area DR, and the photo sensor 406 may be disposed in the display area DR of the liquid crystal display panel 440 and disposed corresponding to the opening OP of the first electrode 308E1, for example, in the top view direction TD Above, each light sensor 406 may be adjacent to the corresponding opening OP, so that each light sensor 406 only detects the detection light passing through the corresponding opening OP, but not limited thereto. For clear illustration, the liquid crystal display panel 440 in FIG. 11 only exemplifies the third substrate 342 , the fourth substrate 344 , the liquid crystal layer 346 and the photo sensor 406 , and omits other elements or film layers, but the invention is not limited thereto. In some embodiments, each opening OP of the first electrode 308E1 may still correspond to one of the first color filter, the second color filter or the third color filter respectively in the top view direction TD. In some embodiments, the display device 4 may further include a touch panel disposed on the liquid crystal display panel 440 .

In this embodiment, the light source 402 may be, for example, an edge-type backlight module, which may include a light-emitting element 462 , a light guide plate 464 , a reflection sheet 466 , brightness enhancement films 468 , 470 and a diffusion sheet 472 . The light emitting element 462 can be disposed on the side of the light guide plate 464, the reflection sheet 466 is disposed under the light guide plate 464, the brightness enhancement films 468 and 470 are sequentially stacked on the light exit surface 464S of the light guide plate 464, and the diffusion sheet 472 is disposed on the light guide plate 464. on bright film 470. The brightness enhancement films 468 and 470 of the present embodiment may have, for example, a plurality of stripes extending along different directions, respectively, but not limited thereto. In some embodiments, the light source 402 can also be a direct type backlight module. In some embodiments, the light source 402 may include a plurality of light emitting diodes, which are distributed and disposed directly under the liquid crystal display panel 440 .

Please refer to FIGS. 12 and 13. FIG. 12 is a schematic top view of a display device according to a fifth embodiment of the present invention, and FIG. 13 is a schematic cross-sectional view of FIG. 12 along line B-B'. As shown in FIGS. 12 and 13 , the difference between the display device 51 provided in this embodiment and the fourth embodiment is that the light source 502 can omit the diffuser, and the liquid crystal panel can be replaced by a local adjustment structure 574 . Specifically, since the light source 502 omits the diffuser, when the display device 51 displays an image, the local adjustment structure 574 disposed between the light source 502 and the liquid crystal display panel 440 needs to have a certain haze, so that the light source 502 is surrounded by a certain haze. The generated light L1 is uniformly diffused, so that the local adjustment structure 574 needs to have the function of diffusing the light when displaying an image. In addition, when the display device 51 performs fingerprint identification, the haze of the part P1 of the local adjustment structure 574 located in the fingerprint identification area FR may be smaller than the haze of the part P2 of the local adjustment structure 574 located outside the fingerprint identification area FR, that is, the local adjustment structure 574 is located outside the fingerprint identification area FR. The penetration rate of the part P1 of the adjustment structure 574 located in the fingerprint identification area FR is greater than the penetration rate of the part P2 of the local adjustment structure 574 located outside the fingerprint identification area FR. For example, the portion P1 of the local adjustment structure 574 located in the fingerprint identification region FR may be transparent. Therefore, the light L1 generated by the light source 502 can penetrate the transparent portion P1 of the local adjustment structure 574 without being diffused by the diffusing sheet, so that the detection light emitted from the fingerprint identification area FR of the liquid crystal display panel 440 can be nearly collimated , thereby enhancing the fingerprint image detected by the light sensor 406 .

In this embodiment, the local adjustment structure 574 may include a first substrate 518, a second substrate 526, a first electrode layer 576, a liquid crystal layer 578 and a second electrode layer 580, wherein the first substrate 518 is disposed on the Between the second substrate 526 and the light source 502, the liquid crystal layer 578 is disposed between the first substrate 518 and the second substrate 526, the first electrode layer 576 is disposed between the liquid crystal layer 578 and the first substrate 518, and the second electrode layer 580 is disposed between the liquid crystal layer 578 and the second substrate 526 . The first electrode layer 576 may include a plurality of adjustment electrodes 576E, which are insulated from each other and disposed in the display region DR. For example, the adjustment electrodes 576E are arranged in an array manner, and the second electrode layer 580 may cover the entire display area DR, but not limited thereto. At least one of the adjustment electrodes 576E may be disposed in the fingerprint identification region FR. For example, one of the adjustment electrodes 576E may cover the fingerprint identification region FR, but not limited thereto. The liquid crystal molecules of the liquid crystal layer 578 in this embodiment may include polymer disperse liquid crystal (PDLC), polymer network liquid crystal (PNLC), cholesteric liquid crystal, or other suitable liquid crystals. liquid crystal. In addition, the local adjustment structure 574 may further include a plurality of wires 582 to electrically connect each adjustment electrode 576E to the control element 584 separately. In some embodiments, the positions of the first electrode layer 576 and the second electrode layer 580 are interchangeable.

The driving method when the display device 51 of the present embodiment performs fingerprint identification will be further described below, and the liquid crystal layer 578 is taken as an example of polymer dispersed liquid crystal, but not limited thereto. Please refer to FIG. 14 together with FIGS. 12 and 13. FIG. 14 shows a timing diagram of driving signals provided to the adjustment electrodes located in and outside the fingerprint identification area. As shown in FIGS. 12 to 14, when the display device 51 performs fingerprint identification, the display device 51 provides a driving signal S4 to the adjustment electrode 576E located in the fingerprint identification area FR, and provides a driving signal S5 to the fingerprint identification area Adjustment electrode 576E outside FR. Since the driving signal S5 provided to the second electrode layer 580 by the display device 51 during fingerprint recognition is the same as or has a similar voltage value to the driving signal S5 provided to the adjustment electrode 576E located outside the fingerprint recognition area FR, it is not illustrated in the 14th Figure. In this embodiment, the driving signal S5 can be a DC signal, which is a certain voltage V1, and the driving signal S4 is provided in the form of alternating current. The driving signal S4 can be, for example, a square wave signal, that is, the peak value V2 of the driving signal S4 can be greater than The voltage V1 of the signal S5 and the valley value V3 may be lower than the voltage V1 of the driving signal S5. For example, the voltage V1 can be the average value of the peak value V2 and the valley value V3, so that the difference between the voltage V1 and the peak value V2 can be the same as the difference between the voltage V1 and the valley value V3, so that the liquid crystal layer 578 in the fingerprint identification area FR The transparency continues to be consistent.

Please refer to FIG. 13 and FIG. 14 at the same time, when the display device 51 performs fingerprint identification, a voltage difference is provided between the adjustment electrode 576E located in the fingerprint identification area FR and the second electrode layer 580, so that the fingerprint identification area FR is located in a voltage difference. The liquid crystal layer 578 in the middle is transparent, so the light L1 generated by the light source 502 can penetrate the transparent portion P1 of the local adjustment structure 574 and the liquid crystal display panel 440 without being scattered, thereby collimating the emitted detection light; However, there is no voltage difference between the adjustment electrode 576E outside the fingerprint identification area FR and the second electrode layer 580 , so that the liquid crystal layer 578 outside the fingerprint identification area FR presents an opaque or semi-transparent haze. The light emitted from the light can be scattered by the liquid crystal layer 578, and the light emitting surface 574S of the local adjustment structure 574 outside the fingerprint identification area FR emits uniform light for displaying images.

Please refer to FIG. 15 , which is a schematic top view of a display device according to a variation of the fifth embodiment of the present invention. The difference between the display device 52 of this variant embodiment and the display device 51 of FIG. 12 is that the first electrode layer 576 of this variant embodiment can include a plurality of first electrode strips 576SE, and the second electrode layer 580 can include a plurality of first electrode strips 576SE. Two electrode strips 580SE, and the first electrode strip 576SE and the second electrode strip 580SE are staggered in the top view direction TD. In this variant embodiment, the first electrode strips 576SE and the second electrode strips 580SE can form a plurality of overlapping regions OR in the top view direction TD, and at least one overlapping region OR can be located in the fingerprint identification region FR to pass through the first electrode The voltage difference between the strips 576SE and the second electrode strips 580SE controls the overlapping area OR located in the fingerprint identification area FR to appear transparent, and the overlapping area OR located outside the fingerprint identification area FR to appear foggy.

Please refer to FIG. 16 , which is a schematic cross-sectional view of a display device according to another variation of the fifth embodiment of the present invention. The difference between the display device 53 of the present variant embodiment and the display device 51 shown in FIG. 12 is that the display device 53 of the present variant embodiment may include an image sensor 592 disposed under the backlight module 594 and having an image sensor The detector 592 can replace the light sensor 406 in the display device 51 for detecting the fingerprint image of the finger. In this variant embodiment, the display device 53 may further include another light source 596 for generating light for detecting the fingerprint image, but it is not limited thereto. In other embodiments, the display device 53 may also not include the light source 596 . The light source 596 can be disposed under the backlight module 594, for example. In this variant embodiment, the backlight module 594 is designed to allow light from the light source 596 to pass through, and to allow the image sensor 592 to detect the reflected light from the finger. For example, the image sensor 592 may include a complementary metal oxide semiconductor (CMOS) image sensing chip, but is not limited thereto, and the light source 596 may include, for example, visible light emitting diodes or invisible light emitting diodes, wherein no Visible light emitting diodes can be, for example, infrared light emitting diodes, but not limited thereto. In some embodiments, the image sensor 592 may also be disposed in the backlight module 594, for example, disposed between the light guide plate and the reflective sheet, but is not limited thereto. The local adjustment structure 574 , the liquid crystal display panel 440 , and the cover plate 134 of this variant embodiment can be applied to the local adjustment structure, the liquid crystal display panel, and the cover plate of the above-mentioned embodiment, so they will not be repeated here.

Please refer to FIG. 17 , which is a block diagram illustrating a control element of a display device according to a sixth embodiment of the present invention. In this embodiment, the display device 61 can be applied to the display device of any of the above-mentioned embodiments, and the following is further described in detail by taking the display device 61 as the display device 51 of FIG. 13 as an example. As shown in FIGS. 13 and 17, the display device 61 may include a backlight control element 686, an integrated control element 688 and a main element 690, which are electrically connected to each other, wherein the integrated control element 688 may include a touch display control element 688T and a fingerprint Identify control element 688F. The backlight control element 686 can be used to control the brightness of the light source 502 and the local adjustment structure 574, so that the local adjustment structure 574 is partially transparent or the whole surface is foggy. The integrated control element 688 can be used to control the light source 502 , the local adjustment structure 574 and the light sensor 406 . The touch display control element 688T can be used to control the touch element to detect the position where the finger approaches or touches, and in the fingerprint recognition mode, when the finger approaches or touches the display area DR, the finger approaches or touches the display area DR. The area is determined as the fingerprint recognition area FR. The fingerprint identification control element 688F can be used to control the light source 502, the local adjustment structure 574 and the light sensor 406, and in the fingerprint identification mode, the fingerprint identification step is performed to obtain the fingerprint image of the finger. Therefore, when the touch display control element 688T in the integrated control element 688 detects that the finger is approaching or touching the display device 61, the information can be directly transmitted to the fingerprint recognition control element 688F, and directly to the backlight control element 686, or It is transmitted to the backlight control element 686 through the main element 690 for fingerprint identification. When the fingerprint identification control element 688F detects a fingerprint image, it can notify the backlight control element 686 to stop fingerprint identification directly or through the main element 690 . In this embodiment, the integrated control element 688 may be a single chip with a microprocessor (MCU). In some embodiments, when the display device 61 can be applied to the display devices of the above-mentioned first to fourth embodiments, the integrated control element 688 can be used to control the light source, the liquid crystal panel and the light sensor.

Please refer to FIG. 18 , which is a block diagram illustrating a control element of a display device according to a variation of the sixth embodiment of the present invention. As shown in FIG. 18 , the difference between the display device 62 of this variant embodiment and the display device 61 of the above-mentioned embodiment is that the touch display control element 688T and the fingerprint recognition control element 688F of the display device 62 of the present variant embodiment are separated from each other, Therefore, the touch display control element 688T and the fingerprint recognition control element 688F can be electrically connected to the main element 690 respectively. In this variant embodiment, the touch display control element 688T can be electrically connected to the fingerprint recognition control element 688F. Therefore, the touch display control element 688T can directly or through the main element 690 send a message to the fingerprint recognition control element 688F, so as to further directly or through the main element 690 to notify the backlight control element 686 to adjust the local adjustment structure 574 to be partially transparent or the entire surface foggy. Likewise, in this variant embodiment, the touch display control element 688T and the fingerprint recognition control element 688F can be a single chip with a microprocessor (MCU), respectively.

The operation method of the above-mentioned display device will be further described below. Please refer to FIG. 19 , which is a schematic flowchart of an operation method of a display device according to a seventh embodiment of the present invention. The display device of this embodiment can also be applied to the display device of any of the above-mentioned embodiments. As shown in FIG. 19 , the operation method of the display device provided in this embodiment includes steps S12 to S30 . For the convenience of description, the following will take the display device 11 in FIG. 3 as an example and further describe the process in FIG. 19 in detail, but it is not limited thereto. First, step S12 is performed to make the display device 11 enter the fingerprint recognition mode. For example, the user can perform step S12 by pressing a function key of the display device 11 or by detecting whether a finger touches the display device 11 through the display device 11 , but not limited thereto. Next, step S16 is performed, that is, a touch detection step is performed to detect whether a finger approaches or touches the display device 11 . When the finger approaches or touches the display area DR of the display device 11 , the area of the display area DR that the finger approaches or touches is determined as the fingerprint recognition area FR. When the display device 11 determines that there is no finger approaching or touching, step S16 is performed again until a finger approaching or touching is detected. In some embodiments, the operating method may further include performing step S14 between steps S12 and S16, so as to use the display device 11 to display the position that can be used as the fingerprint identification area FR, so that the user can know the position that can be used for fingerprint identification. Location.

When the display device 11 determines that a finger is approached or touched, the fingerprint identification step is performed. The fingerprint identification step may include step S18 and step S20. In step S18 , the alignment direction of the liquid crystal molecules 110L of the liquid crystal panel 104 located in the fingerprint identification region FR is adjusted, so that at least a part of the liquid crystal panel 104 located in the fingerprint identification region FR is in a light-transmitting state, and the light L1 generated by the light source 102 is allowed. The finger F is emitted to the finger F through at least a part L2 of the liquid crystal panel 104, wherein the finger F reflects the light L2 into a reflected light L3. For example, in step S18, a voltage difference may be provided between the first electrode 108E1 and the second electrode 112E and/or the first electrode 108E1 and the third electrode layer 114, so that the voltage difference between the first electrode 108E1 and the first electrode 108E1 in the top view direction TD The overlapping liquid crystal molecules 110l may be vertically aligned, so the portion of the liquid crystal panel 104 corresponding to the first electrode 108E1 may be opaque, while the liquid crystal molecules 110L that do not overlap the first electrode 108E1 in the top view direction TD may be horizontally aligned , so the portion of the liquid crystal panel 104 corresponding to the opening OP of the first electrode 108E1 can present a light-transmitting state. Thereby, the light L2 emitted from the light emitting surface 104S of the liquid crystal panel 104 can be collimated. In some embodiments, the display device 11 may not perform step S16, but directly perform step S18 after step S12 or step S14.

In this embodiment, step S18 may optionally include increasing the brightness of the light corresponding to a portion of the liquid crystal panel 104 . Specifically, in order to increase the brightness of the reflected light L3 detected by the light sensor 106, the brightness of the light L2 emitted from the part of the liquid crystal panel 104 located in the fingerprint identification area FR can be further increased in this step S18 . For example, without affecting the image displayed by the display device 11 in the display area outside the fingerprint recognition area FR, a local dimming technique can be used to adjust the height of the light generated by the light source 102 in the fingerprint recognition area. The brightness of the light L1, but not limited thereto.

Then, in step S20, the light sensor 106 is used to detect the reflected light L3 reflected from the finger F, so as to obtain a fingerprint image of the finger F. Then, step S22 is performed to compare the detected fingerprint image with a fingerprint information to determine whether the fingerprint image matches the fingerprint information. In this embodiment, the fingerprint information can be stored in the display device 11 in advance, but is not limited thereto. In some embodiments, the fingerprint information may include at least one fingerprint image.

When the fingerprint image matches the fingerprint information, step S24 is performed to execute a specific function. For example, specific functions may be, but not limited to, allowing the user to use a cell phone, allowing financial transactions, or allowing access to private data. When the fingerprint image does not match the fingerprint information, step S26 may optionally be performed to count the number of times of non-matching.

Next, step S28 is performed to determine whether the number of non-conformities is greater than N, where N can be a positive integer, such as 3 or 5. When the number of times of non-compliance is greater than N, step S30 can be selectively performed to enter another verification mode, so that the user can still execute the specific function. For example, another authentication mode may be an input password mode, a graphic unlock mode, or other suitable authentication mode. When the number of times of non-compliance is less than or equal to N, step S16 may be selectively performed again.

In summary, the display device provided by the present invention can not only use the liquid crystal display panel as a device for displaying images, but also can collimate the detection light penetrating the liquid crystal display panel through the opening of the first electrode or the local adjustment structure, so that the display can be displayed. The light sensor of the device can detect a clear fingerprint image, so the display device can have a fingerprint recognition function in the display area. Thereby, the overall cost of the display device can be effectively reduced. The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

11, 12, 2, 31, 32, 4, 51, 52, 53, 61, 62: Display device 1a: Display surface 102, 402, 502, 596: light source 104, 304, 404: LCD panel 104S, 204S1, 340S, 574S: light-emitting surface 106, 306, 406: light sensor 108, 308, 576: the first electrode layer 108E1, 308E1: the first electrode 108E2: The third electrode 110, 346, 578: liquid crystal layer 110L: Liquid crystal molecules 110G: Grating 112, 312, 580: the second electrode layer 112E: Second electrode 114, 350: the third electrode layer 116, 352: insulating layer 118, 518: The first substrate 120, 348: thin film transistor layer 122: color filter layer 122a: first color filter 122b: Second color filter 122c: Third color filter 124: black matrix layer 126, 526: Second substrate 128, 132, AL1, AL2, AL3: Adhesive layer 130, 230, 330U: Upper polarizer 134: Cover Board 204, 340, 440: LCD panel 204S2: light incident surface 2041: Color filter substrate 2042: Thin Film Transistor Substrates 216, 330L: lower polarizer 342: Third substrate 344: Fourth substrate 354: Fourth electrode layer 356: Self-illuminating display panel 358a: first light-emitting element 358b: second light-emitting element 358c: The third light-emitting element 360: Package cover 462: Light-emitting element 464: light guide plate 466: Reflector 468, 470: Brightness Enhancement Film 472: Diffuser 574: Local adjustment structure 576E: Adjustment Electrodes 576SE: First electrode strip 580SE: Second electrode strip 582: Wire 584: Control element 592: Image Sensor 594: Backlight Module 686: Backlight Control Components 688: Integrated control elements 688T: Touch Display Control Components 688F: Fingerprint identification control element 690: Main element A-A', B-B': section line DR: Display area FR: Fingerprint recognition area F: finger NDR: non-display area OR: overlapping area P1, P2: Partially SPX1, SPX2, SPX3: Subpixels PX1, PX2: Pixels θ: divergence angle W: width L1, L2: light L3: Reflected light OP, 110a, 124a: Opening SL: Slit TFT: Thin Film Transistor SP: Spacer S1: Sync signal S2, S3, S4, S5: drive signal Sx: Display signal T1, T2: picture period DT1, DT2, DT3: Display the driving period BT1, BT2: Interval period TD: Top view direction V1: Voltage V2: Peak V3: Valley S12, S14, S16, S18, S20, S22, S24, S26, S28, S30: Steps

FIG. 1 is a schematic top view of a display device according to a first embodiment of the present invention. FIG. 2 is a schematic top view of a display device corresponding to a single first electrode located in the fingerprint identification area and a third electrode outside the fingerprint identification area according to the first embodiment of the present invention. Fig. 3 is a schematic cross-sectional view taken along line A-A' in Fig. 2 . FIG. 4 is a timing diagram of a synchronization signal, a driving signal of the third electrode, and a driving signal of the first electrode of the liquid crystal panel according to the first embodiment of the present invention. FIG. 5 is a schematic diagram of displaying an image by the display device according to the first embodiment of the present invention. FIG. 6 is a schematic top view of a display device according to a variation of the first embodiment of the present invention. FIG. 7 is a schematic diagram illustrating a method for fingerprint recognition by the display device according to the second embodiment of the present invention. FIG. 8 is a schematic diagram illustrating a method for performing fingerprint recognition on a display device according to a variation of the second embodiment of the present invention. FIG. 9 is a schematic cross-sectional view of a display device according to a third embodiment of the present invention. FIG. 10 is a schematic cross-sectional view of a display device according to a variation of the third embodiment of the present invention. FIG. 11 is a schematic cross-sectional view of a display device according to a fourth embodiment of the present invention. FIG. 12 is a schematic top view of a display device according to a fifth embodiment of the present invention. Fig. 13 is a schematic cross-sectional view taken along line B-B' of Fig. 12 . FIG. 14 is a timing diagram of driving signals provided to the adjustment electrodes located in and outside the fingerprint identification area. FIG. 15 is a schematic top view of a display device according to a variation of the fifth embodiment of the present invention. FIG. 16 is a schematic cross-sectional view of a display device according to another variation of the fifth embodiment of the present invention. FIG. 17 is a block diagram illustrating a control element of a display device according to a sixth embodiment of the present invention. FIG. 18 is a block diagram illustrating a control element of a display device according to a variation of the sixth embodiment of the present invention. FIG. 19 is a schematic flowchart of an operation method of a display device according to a seventh embodiment of the present invention.

1a: Display surface

102: Light source

104: LCD panel

104S: light-emitting surface

106: Light sensor

108: first electrode layer

108E1: first electrode

110: Liquid crystal layer

110L: Liquid crystal molecules

112: the second electrode layer

112E: Second electrode

114: the third electrode layer

116: Insulation layer

118: The first substrate

120: thin film transistor layer

122: color filter layer

122a: first color filter

122b: Second color filter

122c: Third color filter

124: black matrix layer

126: Second substrate

128, 132: Adhesive layer

130: Upper polarizer

134: Cover Board

FR: Fingerprint recognition area

L1, L2 light

L3: Reflected light

OP, 124a: Opening

SL: Slit

TD: Top view direction

F: finger

A-A': section line

Claims (8)

A display device for detecting a fingerprint of a finger, the display device has a display area, and the display device includes: a liquid crystal display panel; a light source, disposed under the liquid crystal display panel; A local adjustment structure is disposed between the light source and the liquid crystal display panel. The local adjustment structure includes a first electrode layer, a liquid crystal layer and a second electrode layer. When the display device performs fingerprint recognition, the finger The display area that is approached or touched is a fingerprint identification area, and the haze of the part of the local adjustment structure located in the fingerprint identification area is smaller than the haze of another part of the local adjustment structure located outside the fingerprint identification area; as well as A plurality of light sensors are arranged in the display area of the liquid crystal display panel. The display device of claim 1, wherein the first electrode layer includes a plurality of adjustment electrodes, and at least one of the plurality of adjustment electrodes is disposed in the display area. The display device of claim 1, wherein the first electrode layer includes a plurality of first electrode strips, the second electrode layer includes a plurality of second electrode strips, and the plurality of first electrode strips and the plurality of first electrode strips The two electrode strips are staggered in a top view direction of the display device. The display device of claim 1, wherein the liquid crystal layer comprises polymer dispersed liquid crystal, polymer network liquid crystal or cholesteric liquid crystal. A method of operating a display device, wherein the display device includes a light source, a liquid crystal panel disposed on the light source, and a plurality of light sensors, the liquid crystal panel has a display area, and the plurality of light sensors are disposed on In the display area, the operation method includes: Enter a fingerprint identification mode; When a finger approaches or touches the display area of the display device, the display area where the finger approaches or touches is determined as a fingerprint identification area, and a fingerprint identification step is performed, wherein the fingerprint identification step includes: Adjust the liquid crystal molecules of the liquid crystal panel located in the fingerprint identification area, so that at least a part of the liquid crystal panel located in the fingerprint identification area presents a light-transmitting state, and allows the light generated by the light source to pass through the at least part of the liquid crystal panel and emit light towards the finger, wherein the finger reflects the light as a reflected light; and Using the plurality of light sensors to detect the reflected light from the finger to obtain a fingerprint image of the finger; and It is judged whether the fingerprint image corresponds to a fingerprint information. The operation method of a display device according to claim 5, wherein the display device further comprises a touch element, and the operation method further comprises a touch detection step using the touch element before the fingerprint identification step is performed , to detect whether the finger approaches or touches the display device, and when the display device determines that the finger approaches or touches, the fingerprint identification step is performed. The operating method of the display device according to claim 6, further comprising using the display device to display the position of the fingerprint identification area before performing the touch detection step. The operation method of the display device according to claim 5, further comprising increasing the brightness of the light corresponding to the at least part of the liquid crystal panel when adjusting the liquid crystal molecules.

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