Optical recognition temperature detection module and display device

Abstract

The present disclosure provides an optical recognition temperature detection module and a display device, which belong to the field of display technology. The optical recognition temperature detection module includes a substrate, including a photosensitive area and a virtual area; a photoelectric sensing structure, including a plurality of first pixel units and a plurality of second pixel units, the first pixel unit is located in the virtual area, including a first thin film transistor and a first photoelectric sensor, the second pixel unit is located in the photosensitive area, including a second thin film transistor and a second photoelectric sensor; a light shielding layer, the orthographic projection of the first pixel unit on the substrate is located within the orthographic projection of the light shielding layer on the substrate; a signal detection unit is connected to a signal sensing line, for detecting the current value of at least part of the first pixel unit, and converting the detected current value into a corresponding temperature response value of the first pixel unit; the current value of the first pixel unit is positively correlated with the temperature of the first pixel unit. The present disclosure integrates the image acquisition function and the temperature detection function to reduce the module volume.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to an optical recognition temperature detection module and a display device. Background Art

[0002] As user demands continue to increase, display product processor performance continues to improve. This performance increase inevitably leads to heating issues. At the same time, the addition of more advanced electronic components within display products has led to increasingly severe heating issues. Operating display products in high-temperature environments can cause component lifespan degradation, performance degradation (such as battery swelling), and pose a safety hazard that can easily burn users. Therefore, monitoring the internal temperature of display products is essential.

[0003] Currently, display products on the market only have separate fingerprint sensors and separate temperature sensors inside, both of which take up a large space, are not conducive to internal space design, and increase equipment preparation costs.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present disclosure is to provide an optical recognition temperature detection module and a display device, which integrate image acquisition function and temperature detection function to reduce the module volume.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0007] According to a first aspect of the present disclosure, there is provided an optical recognition temperature detection module, comprising:

[0008] A substrate, comprising a photosensitive area and a dummy area;

[0009] A photoelectric sensing structure is provided on one side of the substrate, the photoelectric sensing structure including a plurality of gate lines and a plurality of signal sensing lines, and a plurality of pixel units defined by the intersection of the plurality of gate lines and the plurality of signal sensing lines, the plurality of pixel units including:

[0010] a plurality of first pixel units, each of the first pixel units being located in the dummy area, each of the first pixel units comprising a first thin film transistor and a first photosensor, wherein a gate of the first thin film transistor is connected to the corresponding gate line, a first electrode of the first thin film transistor is connected to the corresponding signal sensing line, and a first electrode of the first photosensor is connected to the second electrode of the first thin film transistor;

[0011] a plurality of second pixel units, each of the second pixel units being located in the photosensitive area, each of the second pixel units comprising a second thin film transistor and a second photosensor, a gate of the second thin film transistor being connected to the corresponding gate line, a first electrode of the second thin film transistor being connected to the corresponding signal sensing line, and a first electrode of the second photosensor being connected to the second electrode of the second thin film transistor;

[0012] a light shielding layer provided on a side of the photoelectric sensing structure away from the base substrate, wherein the orthographic projection of the first pixel unit on the base substrate is located within the orthographic projection of the light shielding layer on the base substrate, and the orthographic projection of the second photoelectric sensor on the base substrate does not overlap with the orthographic projection of the light shielding layer on the base substrate;

[0013] A gate driving unit, connected to the gate line, for providing a gate driving signal;

[0014] a signal detection unit connected to the signal sensing line, the signal detection unit being configured to detect a current value of at least a portion of the first pixel units and convert the detected current value into a temperature response value corresponding to the first pixel unit;

[0015] The current value of the first pixel unit is positively correlated with the temperature of the first pixel unit.

[0016] In an exemplary embodiment of the present disclosure, the first pixel units are arranged to form an n×m array, wherein n is the number of rows of the array, m is the number of columns of the array, m≥1, n≥1;

[0017] The signal detection unit is used to detect the current value of each of the first pixel units in k columns of the first pixel units in the array, where 1≤k≤m.

[0018] In an exemplary embodiment of the present disclosure, the optical recognition temperature detection module further includes:

[0019] The signal processing unit is configured to average the temperature response values corresponding to the first pixel units obtained by the signal detection unit to obtain an average temperature response value, compare the average temperature response value with a preset threshold, and output a comparison result.

[0020] In an exemplary embodiment of the present disclosure, the first thin film transistor is an amorphous silicon thin film transistor, and the first photosensor is a PIN photodiode.

[0021] In an exemplary embodiment of the present disclosure, the light shielding layer includes a first light shielding portion located in the virtual area and a second light shielding portion located in the photosensitive area;

[0022] The orthographic projection of the first pixel unit on the base substrate is located within the orthographic projection of the first light shielding portion on the base substrate;

[0023] An orthographic projection of a channel region of the second thin film transistor on the base substrate is located within an orthographic projection of the second light shielding portion on the base substrate.

[0024] In an exemplary embodiment of the present disclosure, the temperature response value of the first pixel unit is a grayscale value of an image corresponding to the first pixel unit.

[0025] In an exemplary embodiment of the present disclosure, the current value of the first pixel unit detected by the signal detection unit satisfies the following relationship:

[0026] I dark =I ds +I n ;

[0027] Among them, I ds is the current value when the first thin film transistor is turned on, I n is the reverse current of the first photosensor.

[0028] In an exemplary embodiment of the present disclosure, the optical recognition temperature detection module further includes:

[0029] a filter film, provided on a side of the light-shielding layer away from the base substrate, for filtering out infrared light, wherein the orthographic projection of the filter film on the base substrate at least covers the photosensitive area;

[0030] A collimating film is provided on a side of the filter film away from the base substrate, wherein the orthographic projection of the collimating film on the base substrate at least covers the photosensitive area, and the collimating film includes a plurality of light-transmitting holes. In a direction perpendicular to the base substrate, a single second photoelectric sensor corresponds to at least one light-transmitting hole.

[0031] According to a second aspect of the present disclosure, there is provided a display device comprising a display panel and the optical recognition temperature detection module as described in the first aspect;

[0032] The display panel is arranged on a side of the light shielding layer away from the base substrate.

[0033] In an exemplary embodiment of the present disclosure, the display device has a fingerprint recognition area and a temperature control area, the display device includes a battery and the optical recognition temperature detection module according to claim 3, the optical sensing structure is located in the fingerprint recognition area, and at least a portion of the battery is located in the temperature control area;

[0034] The preset threshold is set based on a temperature difference between a virtual area corresponding to at least a portion of the first pixel units and the temperature control area.

[0035] The optical recognition temperature detection module provided by the present disclosure has a second pixel unit located in the photosensitive area, including a second thin film transistor and a second photosensor, and the orthographic projection of the second photosensor on the substrate does not overlap with the orthographic projection of the light shielding layer on the substrate, so the second pixel unit can be used for image acquisition. The current value of the first pixel unit is positively correlated with the temperature of the first pixel unit. The signal detection unit is used to detect the current value of at least part of the first pixel unit and convert the detected current value into a corresponding temperature response value. In this way, the temperature response value can correspond to the temperature of the first pixel unit, and the temperature value of the corresponding area of the first pixel unit can be known through the temperature response value, so that the optical recognition temperature detection module provided by the present disclosure has a temperature detection function. In summary, the optical recognition temperature detection module provided by the present disclosure integrates the image acquisition function and the temperature detection function, reduces the module volume, and achieves a high degree of functional integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and other features and advantages of the present disclosure will become more apparent by describing in detail example embodiments thereof with reference to the accompanying drawings.

[0037] Figure 1 1 is a schematic diagram of a planar structure of an optical recognition temperature detection module in an exemplary embodiment of the present disclosure;

[0038] Figure 2 is a schematic cross-sectional view of an optical recognition temperature detection module in an exemplary embodiment of the present disclosure;

[0039] Figure 3 is an equivalent circuit diagram of a first pixel unit and a second pixel unit in an exemplary embodiment of the present disclosure;

[0040] Figure 4 is a schematic cross-sectional view of a display device in an exemplary embodiment of the present disclosure;

[0041] Figure 5 is a schematic diagram of an assembly of a display device in an exemplary embodiment of the present disclosure;

[0042] Figure 6 is a schematic diagram of a temperature-grayscale curve and a modified temperature-grayscale curve in an exemplary embodiment of the present disclosure;

[0043] Figure 7 FIG. 4 is a flow chart of a temperature monitoring application for a display device in an exemplary embodiment of the present disclosure.

[0044] The main components in the figure are described as follows:

[0045] 10-Optical recognition temperature detection module; 11-Array substrate; 100-Base substrate; 110-Photosensitive area; 120-Dummy area; 121-Temperature detection area; 200-Photoelectric sensing structure; 210-Gate line; 220-Signal sensing line; 230-First pixel unit; 231-First thin film transistor; 232-First photosensor; 240-Second pixel unit; 241-Second thin film transistor; 242-Second photosensor; 201-First metal layer; 202-First insulating layer; 203-Active layer; 204-Second metal layer; 205-Second insulating layer; 206-Photosensitive Material layer; 207-third metal layer; 208-third insulating layer; 209-bias voltage layer; 211-fourth insulating layer; 212-protective layer; 213-top shielding layer; 300-light-shielding layer; 310-first light-shielding portion; 320-second light-shielding portion; 400-gate drive unit; 500-signal detection unit; 601-first optical adhesive layer; 602-filter film; 603-second optical adhesive layer; 604-collimating film; 20-display panel; 31-light-shielding layer; 32-metal layer; 30-opening; 40-middle frame; 41-adhesive layer; 42-module frame; 50-battery; 60-back cover. DETAILED DESCRIPTION

[0046] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of the embodiments of the present disclosure.

[0047] In the drawings, the thickness of regions and layers may be exaggerated for clarity. The same reference numerals in the drawings denote the same or similar structures, and thus their detailed description will be omitted.

[0048] The described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure can be practiced without one or more of the specific details, or other methods, components, materials, etc. can be adopted. In other cases, well-known structures, materials or operations are not shown or described in detail to avoid obscuring the main technical ideas of the present disclosure.

[0049] When a structure is “on” another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is “directly” disposed on the other structure, or that the structure is “indirectly” disposed on the other structure via another structure.

[0050] The terms "a," "an," and "the" are used to indicate the presence of one or more elements / components; the terms "including" and "having" are used to indicate an open-ended inclusiveness and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc. The terms "first," "second," etc. are used merely as labels and do not limit the quantity of the items to which they refer.

[0051] Fingerprint recognition sensors are widely used in the field of identity verification. Product areas where they have been implemented or have great prospects for adoption include consumer electronics such as mobile phones, security identity authentication, and smart door locks. Under-screen fingerprint recognition technology is primarily implemented by placing a fingerprint recognition module beneath the display. When a user presses the display corresponding to the fingerprint recognition area, the fingerprint recognition module captures the fingerprint image or light reflection information corresponding to the fingerprint, thereby enabling fingerprint recognition. Related technologies typically only have separate fingerprint recognition sensors and temperature sensors within display products. Both occupy a large amount of space, hindering internal space design and increasing device manufacturing costs.

[0052] like Figure 1 、 Figure 2 and Figure 3As shown, in an embodiment of the present disclosure, an optical recognition temperature detection module 10 is provided, comprising a base substrate 100, a photoelectric sensing structure 200, a light shielding layer 300, a gate driving unit 400, and a signal detection unit 500. The base substrate 100 comprises a photosensitive area 110 and a dummy area 120; the photoelectric sensing structure 200 is disposed on one side of the base substrate 100. The photoelectric sensing structure 200 comprises a plurality of gate lines 210 and a plurality of signal sensing lines 220, as well as a plurality of pixel units defined by the intersection of the plurality of gate lines 210 and the plurality of signal sensing lines 220. The plurality of pixel units comprises a plurality of first pixel units 230 and a plurality of second pixel units 240. A plurality of first pixel units 230 are provided. The first pixel units 230 are located in the dummy area 120 and include a first thin film transistor 231 and a first photosensor 232. The gate of the first thin film transistor 231 is connected to the corresponding gate line 210, the first electrode of the first thin film transistor 231 is connected to the corresponding signal sensing line 220, and the first electrode of the first photosensor 232 is connected to the second electrode of the first thin film transistor 231. A second pixel unit 240 is located in the photosensitive area 110 and includes a second thin film transistor 241 and a second photosensor 242. A light shielding layer 300 is provided on a side of the photosensor structure 200 away from the substrate 100. The orthographic projection of the first pixel unit 230 on the substrate 100 is located within the orthographic projection of the light shielding layer 300 on the substrate 100. The orthographic projection of the second photosensor 242 on the substrate 100 does not overlap with the orthographic projection of the light shielding layer 300 on the substrate 100. The gate driving unit 400 is connected to the gate line 210 for providing a gate driving signal; the signal detection unit 500 is connected to the signal sensing line 220, and the signal detection unit 500 is used to detect the current value of at least part of the first pixel unit 230 and convert the detected current value into a corresponding temperature response value of the first pixel unit 230; wherein the current value of the first pixel unit 230 is positively correlated with the temperature of the first pixel unit 230.

[0053] The optical recognition temperature detection module 10 provided by the present disclosure has a second pixel unit 240 located in the photosensitive area 110, including a second thin film transistor 241 and a second photosensor 242, and the orthographic projection of the second photosensor 242 on the substrate 100 does not overlap with the orthographic projection of the light shielding layer 300 on the substrate 100, so that the second pixel unit 240 can be used for image acquisition. The current value of the first pixel unit 230 is positively correlated with the temperature of the first pixel unit 230. The signal detection unit 500 is used to detect the current value of at least part of the first pixel unit 230 and convert the detected current value into a corresponding temperature response value. In this way, the temperature response value can correspond to the temperature of the first pixel unit 230, and the temperature value of the corresponding area of the first pixel unit 230 can be obtained through the temperature response value, so that the optical recognition temperature detection module 10 provided by the present disclosure has a temperature detection function. In summary, the optical recognition temperature detection module 10 provided by the present disclosure integrates the image acquisition function and the temperature detection function, reduces the module volume, and achieves a high degree of functional integration.

[0054] The components of the optical recognition temperature detection module 10 provided in the embodiment of the present disclosure are described in detail below with reference to the accompanying drawings:

[0055] like Figures 1 to 3 As shown, the optical recognition and temperature detection module 10 provided by the present disclosure can be used for fingerprint recognition and temperature detection. Figure 1 is a top view of the optical recognition temperature detection module 10 in the embodiment of the present disclosure, Figure 2 FIG. 1 is a schematic cross-sectional view of the optical recognition temperature detection module 10 in an embodiment of the present disclosure.

[0056] The optical recognition temperature detection module 10 provided in the present disclosure includes a base substrate 100 , a photoelectric sensing structure 200 , a light shielding layer 300 , a gate driving unit 400 and a signal detection unit 500 .

[0057] The base substrate 100 may be a glass substrate or a flexible substrate. The base substrate 100 has a photosensitive area 110 and a virtual area 120. The virtual area 120 may be located on one side, both sides, or multiple sides of the photosensitive area 110, which is not limited in the present disclosure. Figure 1 In the illustrated embodiment, the dummy area 120 is located on both sides of the photosensitive area 110 in the first direction X.

[0058] The photoelectric sensing structure 200 is disposed on one side of the base substrate 100. The photoelectric sensing structure 200 includes a plurality of gate lines 210 and a plurality of signal sensing lines 220, as well as a plurality of pixel units defined by the intersection of the plurality of gate lines 210 and the plurality of signal sensing lines 220. The plurality of gate lines 210 may extend along a first direction X and be arranged at intervals along a second direction Y. The plurality of signal sensing lines 220 may extend along the second direction Y and be arranged at intervals along the first direction X. The first direction X and the second direction Y form an angle, which may be any angle greater than 0° and less than or equal to 90°.

[0059] The plurality of pixel units include a plurality of first pixel units 230 and a plurality of second pixel units 240. The first pixel unit 230 is located in the virtual area 120 and includes a first thin-film transistor 231 and a first photosensor 232. The gate of the first thin-film transistor 231 is connected to the corresponding gate line 210, the first electrode of the first thin-film transistor 231 is connected to the corresponding signal sensing line 220, and the first electrode of the first photosensor 232 is connected to the second electrode of the first thin-film transistor 231. The first pixel unit 230 is configured for temperature detection. The second pixel unit 240 is located in the photosensitive area 110 and includes a second thin-film transistor 241 and a second photosensor 242. The gate of the second thin-film transistor 241 is connected to the corresponding gate line 210, the first electrode of the second thin-film transistor 241 is connected to the corresponding signal sensing line 220, and the first electrode of the second photosensor 242 is connected to the second electrode of the second thin-film transistor 241. The second pixel unit 240 is configured for fingerprint recognition.

[0060] In some embodiments of the present disclosure, the second thin film transistor 241 may be an amorphous silicon thin film transistor, and the second photosensor 242 may be a PIN photodiode.

[0061] The gate drive unit 400 is connected to the gate line 210 and is used to provide a drive signal. Specifically, the gate drive unit 400 is used to provide a gate drive signal to the corresponding first thin film transistor 231 or the second thin film transistor 241 to control the opening or closing of the first thin film transistor 231 or the second thin film transistor 241. The pixel units in the same row can be connected to the same gate line 210, but are not limited to this. The gate drive unit 400 is provided in a gate drive chip, which can be provided on one side of the array substrate 11 formed by at least the base substrate 100 and the photoelectric sensing structure 200, and is connected to the array substrate 11 through a chip-on-chip film, or can be integrated on the array substrate 11, which is not specifically limited in the present disclosure.

[0062] The signal detection unit 500 is connected to the signal sensing line 220. In some embodiments, the signal detection unit 500 can be used to detect the electrical signal of the pixel unit, such as the current value. Pixel units in the same column can be connected to the same signal sensing line 220. The signal detection unit 500 is provided in a readout chip, which can be provided on one side of the array substrate 11 formed by at least the base substrate 100 and the photoelectric sensing structure 200, and connected to the array substrate 11 via a chip-on-film. Alternatively, the chip can be integrated into the array substrate 11, and the present disclosure does not specifically limit this.

[0063] like Figure 2 As shown, the photoelectric sensing structure 200 is a multi-layer film stack structure. The photoelectric sensing structure 200 includes a first metal layer 201, a first insulating layer 202, an active layer 203, and a second metal layer 204 stacked in a direction away from the substrate 100. The first metal layer 201 includes the gates of the first and second thin-film transistors 231 and 241, as well as the gate line 210. The active layer 203 includes the channel regions of the first and second thin-film transistors 231 and 241. The material of the active layer 203 can be single-crystalline silicon or amorphous silicon, preferably amorphous silicon. The second metal layer 204 includes the first and second electrodes of the first and second thin-film transistors 231 and 241, as well as the first electrodes of the first and second photosensors 232 and 242. It may also include at least a portion of the signal sensing line 220.

[0064] Furthermore, the photoelectric sensing structure 200 also includes a second insulating layer 205, a photosensitive material layer 206, a third metal layer 207, a third insulating layer 208, and a bias voltage layer 209. The second insulating layer 205 is disposed on the side of the second metal layer 204 away from the substrate 100, and the photosensitive material layer 206 is disposed on the side of the second insulating layer 205 away from the substrate 100. The photosensitive material layer 206 is connected to the second metal layer 204 via a via. Specifically, the orthographic projection of the photosensitive material layer 206 on the substrate 100 at least partially overlaps with the orthographic projections of the first electrodes of the first photosensor 232 and the second photosensor 242 on the substrate 100. The third metal layer 207 is disposed on the side of the photosensitive material layer 206 away from the substrate 100 and includes the second electrodes of the first photosensor 232 and the second photosensor 242. Third insulating layer 208 is disposed on a side of third metal layer 207 away from substrate 100. Bias voltage layer 209 is disposed on a side of third insulating layer 208 away from substrate 100. Bias voltage layer 209 is a conductive layer used to apply a bias voltage. Bias voltage layer 209 is connected to the second electrodes of first photosensor 232 and second photosensor 242 through vias in first insulating layer 202.

[0065] In some embodiments of the present disclosure, the optical recognition temperature detection module 10 further includes a light shielding layer 300, which is disposed on a side of the photoelectric sensing structure 200 away from the base substrate 100. The orthographic projection of the first pixel unit 230 on the base substrate 100 is located within the orthographic projection of the light shielding layer 300 on the base substrate 100, and the orthographic projection of the second photoelectric sensor 242 on the base substrate 100 does not overlap with the orthographic projection of the light shielding layer 300 on the base substrate 100. The thickness of the light shielding layer 300 can be 3000 to 5000A to ensure the light shielding effect. The light shielding layer 300 completely blocks the first pixel unit 230 located in the virtual area 120, thereby preventing light from entering the second photoelectric sensor 242 and generating a photoelectric signal. The second photoelectric sensor 242 is not blocked by the light shielding layer 300, and light can enter the second photoelectric sensor 242 and generate a photoelectric signal.

[0066] In some embodiments of the present disclosure, the light-shielding layer 300 includes a first light-shielding portion 310 located in the dummy region 120 and a second light-shielding portion 320 located in the photosensitive region 110. The orthographic projection of the first pixel unit 230 on the substrate 100 is located within the orthographic projection of the first light-shielding portion 310 on the substrate 100. The orthographic projection of the channel region of the second thin-film transistor 241 on the substrate 100 is located within the orthographic projection of the second light-shielding portion 320 on the substrate 100. The second light-shielding portion 320 is used to prevent external light from affecting the electrical characteristics of the second thin-film transistor 241 when it reaches the channel region.

[0067] In some embodiments of the present disclosure, the optical recognition temperature detection module 10 further includes a fourth insulating layer 211, a protective layer 212, and a top shielding layer 213. The fourth insulating layer 211 is disposed between the bias voltage layer 209 and the light shielding layer 300. The protective layer 212 is disposed on the side of the light shielding layer 300 away from the base substrate 100, and the top shielding layer 213 is disposed on the side of the protective layer 212 away from the base substrate 100. The orthographic projections of the first pixel unit 230 and the second pixel unit 240 on the base substrate 100 are located within the orthographic projection of the top shielding layer 213 on the base substrate 100, that is, the top shielding layer 213 completely covers the second pixel unit 240 of the photosensitive area 110 and the first pixel unit 230 of the virtual area 120. The top shielding layer 213 is connected to the light shielding layer 300 through the vias on the protective layer 212, effectively preventing the problem of charge accumulation on the light shielding layer 300.

[0068] like Figure 3As shown, the second pixel unit 240 can complete the acquisition of images, such as the acquisition of fingerprint images. Specifically, the second photosensor is equivalent to a capacitor under a negative bias, for example, the first electrode (N electrode) of the second photosensor is applied with a voltage Vdd, and the second electrode (P electrode) of the second photosensor is applied with a voltage Vcom, Vcom < Vdd, such as Vcom = -6V, Vdd = 1V. After being irradiated with light, the second photoelectric sensor 242 generates free electrons, which is equivalent to capacitor discharge, and the voltage of the first electrode begins to drop, such as from 1V to -6V. The gate drive unit 400 turns on the second thin film transistor 241 in sequence, and the signal sensing unit reads the charge loss of each second pixel unit 240 in sequence and converts it into a grayscale image. Different second photosensors 242 can receive different light (light reflected from the fingerprint surface), so the corresponding electrical signals generated by the second photosensors 242 are also different, so that different grayscale images can be converted. After the second thin film transistor 241 is turned on for a period of time, the charge loss is completely read out. At the same time, the first electrode of the second light sensor is loaded with Vdd again, such as 1V, which is equivalent to charging the capacitor. Then the second thin film transistor 241 is turned off, and the charging and discharging cycle is repeated.

[0069] The first pixel unit 230 can perform temperature detection, utilizing the characteristics of thin-film transistors and PIN photodiodes. Amorphous silicon thin-film transistors are highly sensitive to temperature, and the temperature sensitivity of the thin-film transistor can be altered by changing the doping concentration of heavily doped amorphous silicon (n+a-Si) between the source / drain electrodes and the amorphous silicon semiconductor, thereby changing the material properties. When such a thin-film transistor operates in the saturation region, its channel current is positively correlated with temperature. Therefore, the temperature condition can be reflected by measuring the channel current value of the device.

[0070] Specifically, when the thin film transistor operates in the saturation region, the channel current I ds =μ n *C i *W(V gs -V th ) / 2L, where μ n is the electron drift mobility in the channel, C i is the capacitance per unit area of the gate dielectric layer, W and L are the length and width of the channel respectively, V gs and V th are the gate-source voltage and threshold voltage respectively. Among the above parameters, the one that is related to temperature is V th and μ n According to ΔV th / V th =(E F -E C )*ΔT / kT 2 , where ΔV this the threshold voltage change, E F is the Fermi level of amorphous silicon, E C is the conduction band energy level of amorphous silicon, ΔT is the temperature change, T is the temperature, and k is the Boltzmann constant. From this formula, we can see that the threshold voltage V th As the temperature increases, it decreases. According to Δμ n / μ n =ΔT*(1+E a / kT) / T, where Δμ n is the change in electron drift mobility in the channel, ΔT is the temperature change, T is the temperature, k is the Boltzmann constant, E a is the thermal activation energy of amorphous silicon. From this formula, we can know that μ n As the temperature increases, it increases. In summary, when the operating temperature of the thin film transistor increases, the electron channel electron mobility μ n and threshold voltage V th The change of will also increase the channel current, that is, the channel current I ds Positively correlated with temperature.

[0071] For a PIN photodiode, when a reverse voltage is applied, the reverse current is positively correlated with the temperature. Specifically, the reverse current formula is I n = C*T*ex((-q*V0) / (k*T)), where C is a constant related to the PIN junction area and doping concentration, and is also constant within a certain range. V0 is the potential difference between the PIN conduction band and the valence band, and for a given junction material, V0 is a constant. Therefore, as temperature increases, the reverse current also positively correlates with temperature. Specifically, as temperature rises, minority carrier motion in the PIN intensifies, carrier activity increases, and the reverse current increases.

[0072] In the present disclosure, the first pixel unit 230 of the virtual area 120 is shielded by the light shielding layer 300. Therefore, the first thin film transistor 231 and the first photosensor 232 are not illuminated by light and no photocurrent is generated. When the first thin film transistor 231 is turned on, only the current Ids of the first thin film transistor 231 and the reverse current In of the first photosensor 232 flow out. Therefore, the total current I read out of the first pixel unit 230 is dark =I ds +I n , that is, the current value of the first pixel unit 230 is positively correlated with the temperature, that is, I dark =α*ΔT, T is temperature, α is the coefficient.

[0073] The signal detection unit 500 is connected to the signal sensing line 220 and is configured to detect the current value of at least a portion of the first pixel unit 230 and convert the detected current value into a temperature response value corresponding to the first pixel unit 230. The temperature response value of the first pixel unit 230 is the image grayscale value corresponding to the first pixel unit 230. When using the first pixel unit 230 for temperature detection, the gate drive unit controls the corresponding first thin-film transistor 231 to turn on. The signal detection unit 500 detects the current value of the corresponding first pixel unit 230 and converts it into the corresponding temperature response value, i.e., the image grayscale value. Because the current value of the first pixel unit 230 is positively correlated with the temperature, the temperature value of the area corresponding to the first pixel unit 230 can be detected.

[0074] Specifically, within a certain temperature range, such as 20°C-80°C, which range can be selected according to the possible range of the actual display product, the image grayscale values corresponding to certain first pixel units 230 in the virtual area 120 at different temperatures within the temperature range can be tested, and the average value can be taken to make a temperature-grayscale curve, and the corresponding relationship between temperature and image grayscale value can be found, so that the image grayscale value can obtain the corresponding temperature value.

[0075] like Figure 1 As shown, in some embodiments of the present disclosure, the current value of all or part of the first pixel units 230 in the virtual area 120 can be detected, that is, part of the first pixel units 230 are selected for temperature monitoring, so that a smaller number of pixels are turned on for use, which is beneficial to reducing the power consumption of the module. For example, the first pixel units 230 are arranged to form an n×m array, where n is the number of rows of the array, m is the number of columns of the array, m≥1, n≥1; the signal detection unit 500 is used to detect the current value of each first pixel unit 230 in the k columns of first pixel units 230 in the array, 1≤k≤m. The k columns of first pixel units 230 constitute the temperature detection area 121. Then the number of the detected first pixel units 230 is k×n. The positions of the selected k columns of first pixel units 230 are not limited. In Figure 1 In the illustrated embodiment, the virtual areas 120 are located on the left and right sides of the photosensitive area 110. The virtual areas 120 on either side have columns a and b of first pixel units 230, respectively, where a + b = m. Partial columns of the first pixel units 230 on both sides can be selected for temperature detection. For example, column c of the first pixel units 230 in column a on the left side is selected, where c ≤ a, and column d of the first pixel units 230 in column b on the right side is selected, where d < b and c + d = k.

[0076] The optical recognition temperature detection module 10 provided herein can implement temperature monitoring using the first pixel unit 230. In some embodiments, the optical recognition temperature detection module 10 further includes a signal processing unit configured to average the temperature response values corresponding to the first pixel unit 230 obtained by the signal detection unit 500 to obtain an average temperature response value, compare the average temperature response value with a preset threshold, and output a comparison result. The signal processing unit can be integrated into the readout chip.

[0077] In some embodiments, the average temperature response value is the average image grayscale value, and the preset threshold is the image grayscale value threshold, the value of which can be set according to actual conditions. For example, the average grayscale threshold corresponding to the measured temperature of the multiple first pixel units 230 being 50°C can be set as the preset threshold. The preset threshold can include multiple thresholds, such as a first threshold and a second threshold. During the comparison, the signal processing unit can compare the obtained average temperature response value, such as the average image grayscale value, with the first threshold and the second threshold, and output the comparison result. Different responses can be made based on different comparison results, such as activating the temperature detection function of the optical recognition temperature detection module 10. When the measured average image grayscale value of the multiple first pixel units 230 is less than the first threshold, the module temperature is monitored at a low frequency. When the measured average image grayscale threshold of the multiple first pixel units 230 is greater than the first threshold, the module temperature is monitored at a high frequency. When the measured average image grayscale threshold of the multiple first pixel units 230 is greater than the second threshold, certain functions in the module are disabled to reduce module power consumption and thereby reduce module temperature.

[0078] In some embodiments of the present disclosure, the first pixel unit 230 located in the virtual area 120 may also be configured to perform noise reduction processing on the electrical signal generated by the second pixel unit 240. For example, the current value of the first pixel unit 230 is used as a reference signal, and noise reduction processing is performed on the electrical signal generated by the second pixel unit 240 based on the reference signal. Furthermore, the first thin-film transistor 231 and the second thin-film transistor 241 have the same structure, and the first photosensor 232 and the second photosensor 242 have the same structure, to ensure that the capacitance and resistance of the virtual area 120 are substantially the same as those of the photosensitive area 110.

[0079] like Figure 4As shown, the optical recognition temperature detection module 10 provided by the present disclosure also includes a filter film 602 and a collimating film 604. The filter film 602 is provided on the side of the light shielding layer 300 away from the base substrate 100. The filter film 602 can be an infrared filter layer for filtering out infrared light in the light. Under strong ambient light, most of the light passing through the finger is infrared light (wavelength range is 760nm ~ 1000nm). The infrared filter layer blocks infrared light, thereby reducing the impact of ambient light on the second photoelectric sensor 242 and improving the accuracy of image acquisition. The collimating film 604 is provided on the side of the filter film 602 away from the base substrate 100. The orthographic projection of the collimating film 604 on the base substrate 100 covers at least the photosensitive area 110. The collimating film 604 includes a plurality of light-transmitting holes. In the direction perpendicular to the base substrate 100, a single second photoelectric sensor 242 corresponds to at least one light-transmitting hole. The light-transmitting hole plays a role in collimating the light. Specifically, the base substrate 100, the photoelectric sensing structure 200, the light shielding layer 300, and the top shielding layer 213 constitute the array substrate 11. The filter film 602 and the collimating film 604 are stacked on one side of the array substrate 11. Furthermore, the filter film 602 and the array substrate 11 can be bonded together via a first optical adhesive layer 601, and the filter film 602 and the collimating film 604 can be bonded together via a second optical adhesive layer 603.

[0080] like Figure 4 and Figure 5 As shown, the optical recognition temperature detection module 10 provided by the present disclosure can be used for temperature monitoring of display products. The present disclosure also discloses a display device, comprising a display panel 20 and the optical recognition temperature detection module 10 in any of the above embodiments. The display panel 20 is arranged on the side of the light-shielding layer 300 away from the base substrate 100. Specifically, the display panel 20 is arranged on the side of the collimating film 604 away from the base substrate 100. The display panel 20 may be an OLED (Organic Light-Emitting Diode) display panel 20. The display panel 20 may include structures such as a pixel driving circuit board, a light-emitting device layer, a color filter layer and a cover plate, and the specific details of the present disclosure are not described in detail here. When fingerprint collection is performed, the fingerprint contacts the display panel 20, and the light emitted by the display panel 20 is reflected on the fingerprint surface and then directed toward the photoelectric sensing structure 200. The second pixel unit 240 in the photoelectric sensing structure 200 generates a corresponding electrical signal based on the received light (light reflected by the fingerprint surface). The electrical signal is transmitted to the signal detection unit 500 through the second thin-film transistor 241, the signal sensing line 220, etc. The signal detection unit 500 can complete fingerprint image collection and recognition by identifying the valley ridge image of the fingerprint at the corresponding position based on the received electrical signal.

[0081] The display device further includes a light-shielding layer 31 and a metal layer 32, such as a graphite layer and a copper foil layer. The metal layer 32 is disposed on a side of the light-shielding layer 31 away from the display panel 20. Both the metal layer 32 and the light-shielding layer 300 have openings 30 formed therein. The orthographic projection of the photoelectric sensing structure 200 on the display panel 20 is located within the orthographic projection of the openings 30 on the display panel 20.

[0082] The display device also includes a middle frame 40, to which the optical recognition temperature detection module 10 and the display panel 20 can be mounted. The optical recognition temperature detection module 10 can be connected to the middle frame 40 via an adhesive layer 41. For example, a module frame 42 is provided on the middle frame 40, to which the optical recognition temperature detection module 10 is mounted. Furthermore, the display device may also include a battery 50, a back cover 60, and the like.

[0083] In some embodiments of the present disclosure, the display device has a fingerprint recognition area 01 and a temperature control area 02, the optical recognition temperature detection module 10 is located in the fingerprint recognition area 01, and at least part of the battery 50 is located in the temperature control area 02. The temperature detection function of the optical recognition temperature detection module 10 can be used to monitor the temperature of the display device. Furthermore, in the above embodiment, the preset threshold value of the temperature detection function of the optical recognition temperature detection module 10 can be set based on the temperature difference between the temperature control area 02 and the fingerprint recognition area 01 of the display device, specifically based on the temperature difference between the temperature control area 02 and the virtual area 120 corresponding to at least part of the pixel units. This method can compensate for the temperature difference in higher temperature areas such as the battery 50 of the display device, making the temperature monitoring of the display device more reasonable.

[0084] like Figure 6 As shown, in the above embodiment, a temperature-grayscale curve is drawn for certain first pixel units 230 in the virtual area 120. When used in a display device, based on the temperature difference between the temperature control area 02 and the virtual area 120 corresponding to at least some of the pixel units, a modified temperature-grayscale curve is generated that takes into account the temperature difference, and a preset threshold is set based on the curve.

[0085] like Figure 7 As shown, the following example illustrates the application scenario of the temperature monitoring function of the display device. It includes the following steps:

[0086] Step S100: Turn on the temperature monitoring function of the display device, that is, turn on the temperature detection function of the optical recognition temperature detection module 10. The preset threshold includes a first threshold and a second threshold, the second threshold being greater than the first threshold. The preset threshold can be a grayscale threshold or a temperature threshold corresponding to the grayscale threshold.

[0087] Step S200, after turning on the temperature monitoring function, the optical recognition temperature detection module 10 monitors the internal temperature of the display device at a lower frequency to determine whether the temperature exceeds the first threshold. When the temperature does not exceed the first threshold, the low-frequency monitoring is continued. When the temperature exceeds the first threshold, the display device can remind the user of the temperature of the display device and start monitoring the internal temperature of the display device at a higher frequency. If the temperature of the display device rises further and exceeds the second threshold, some non-essential components in the display device are disconnected to protect the components and reduce power consumption. In addition, if the temperature does not exceed the second threshold within a period of time after exceeding the first threshold, it can be monitored at a lower frequency or at a higher frequency, and there is no specific limitation.

[0088] It should be understood that the present disclosure is not limited in its application to the detailed structure and arrangement of the components set forth in this specification. The present disclosure is capable of other embodiments and can be implemented and executed in a variety of ways. The aforementioned variations and modifications fall within the scope of the present disclosure. It should be understood that the present disclosure disclosed and defined in this specification extends to all alternative combinations of two or more individual features mentioned or evident in the text and / or the drawings. All of these different combinations constitute multiple alternative aspects of the present disclosure. The embodiments of this specification illustrate the best mode known for implementing the present disclosure and will enable those skilled in the art to utilize the present disclosure.

Claims

1. An optical recognition temperature detection module, characterized in that: include: A substrate, comprising a photosensitive area and a dummy area; A photoelectric sensing structure is provided on one side of the substrate, the photoelectric sensing structure including a plurality of gate lines and a plurality of signal sensing lines, and a plurality of pixel units defined by the intersection of the plurality of gate lines and the plurality of signal sensing lines, the plurality of pixel units including: a plurality of first pixel units, each of the first pixel units being located in the dummy area, each of the first pixel units comprising a first thin film transistor and a first photosensor, wherein a gate of the first thin film transistor is connected to the corresponding gate line, a first electrode of the first thin film transistor is connected to the corresponding signal sensing line, and a first electrode of the first photosensor is connected to the second electrode of the first thin film transistor; a plurality of second pixel units, each of the second pixel units being located in the photosensitive area, each of the second pixel units comprising a second thin film transistor and a second photosensor, a gate of the second thin film transistor being connected to the corresponding gate line, a first electrode of the second thin film transistor being connected to the corresponding signal sensing line, and a first electrode of the second photosensor being connected to the second electrode of the second thin film transistor; a light shielding layer provided on a side of the photoelectric sensing structure away from the base substrate, wherein the orthographic projection of the first pixel unit on the base substrate is located within the orthographic projection of the light shielding layer on the base substrate, and the orthographic projection of the second photoelectric sensor on the base substrate does not overlap with the orthographic projection of the light shielding layer on the base substrate; A gate driving unit, connected to the gate line, for providing a gate driving signal; a signal detection unit connected to the signal sensing line, the signal detection unit being configured to detect a current value of at least a portion of the first pixel units and convert the detected current value into a temperature response value corresponding to the first pixel unit; The first thin film transistor operates in a saturation region, and the current value of the first pixel unit is positively correlated with the temperature of the first pixel unit.

2. The optical recognition temperature detection module according to claim 1, characterized in that: The first pixel units are arranged to form an n×m array, where n is the number of rows of the array, m is the number of columns of the array, m≥1, n≥1; The signal detection unit is used to detect the current value of each of the first pixel units in k columns of the first pixel units in the array, where 1≤k≤m.

3. The optical recognition temperature detection module according to claim 1, characterized in that: The optical recognition temperature detection module also includes: The signal processing unit is configured to average the temperature response values corresponding to the first pixel units obtained by the signal detection unit to obtain an average temperature response value, compare the average temperature response value with a preset threshold, and output a comparison result.

4. The optical recognition temperature detection module according to claim 1, characterized in that: The first thin film transistor is an amorphous silicon thin film transistor, and the first photosensor is a PIN photodiode.

5. The optical recognition temperature detection module according to claim 1, characterized in that: The light shielding layer includes a first light shielding portion located in the virtual area and a second light shielding portion located in the photosensitive area; The orthographic projection of the first pixel unit on the base substrate is located within the orthographic projection of the first light shielding portion on the base substrate; An orthographic projection of a channel region of the second thin film transistor on the base substrate is located within an orthographic projection of the second light shielding portion on the base substrate.

6. The optical recognition temperature detection module according to claim 1, characterized in that: The temperature response value of the first pixel unit is the image grayscale value corresponding to the first pixel unit.

7. The optical recognition temperature detection module according to claim 1, characterized in that: The current value of the first pixel unit detected by the signal detection unit satisfies the following relationship: I dark =I ds +I n ; Among them, I ds is the current value when the first thin film transistor is turned on, I n is the reverse current of the first photosensor.

8. The optical recognition temperature detection module according to claim 1, characterized in that: The optical recognition temperature detection module also includes: a filter film, provided on a side of the light-shielding layer away from the base substrate, for filtering out infrared light, wherein the orthographic projection of the filter film on the base substrate at least covers the photosensitive area; A collimating film is provided on a side of the filter film away from the base substrate, wherein the orthographic projection of the collimating film on the base substrate at least covers the photosensitive area, and the collimating film includes a plurality of light-transmitting holes. In a direction perpendicular to the base substrate, a single second photoelectric sensor corresponds to at least one light-transmitting hole.

9. A display device, characterized in that: comprising a display panel and an optical recognition temperature detection module according to any one of claims 1 to 8; The display panel is arranged on a side of the light shielding layer away from the base substrate.

10. A display device, characterized in that: The display device has a fingerprint recognition area and a temperature control area, the display device includes a battery and the optical recognition temperature detection module according to claim 3, the optical recognition temperature detection module is located in the fingerprint recognition area, and at least a portion of the battery is located in the temperature control area; The preset threshold is set based on a temperature difference between a virtual area corresponding to at least a portion of the first pixel units and the temperature control area.

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