WO2019071559A1 - Optical image sensing system - Google Patents

Abstract

An optical image sensing system (100), comprising a signal transmitting module (10), a signal receiving module (20), and a signal processing module (30). The signal transmitting module (10) comprises a luminous source (11) and a pulse frequency control unit (12). The pulse frequency control unit (12) generates a pulse frequency control signal. The luminous source (11) emits a periodic pulsed optical signal of a preset frequency according to the pulse frequency control signal. The pulsed optical signal of each period comprises a first phase optical signal of first intensity and a second phase optical signal of second intensity. The signal receiving module (20) receives the first phase optical signal and the second phase optical signal reflected by an object, processes the first phase optical signal reflected by the object as a first phase electric signal, and processes the second phase optical signal reflected by the object as a second phase electric signal. The signal processing module (30) performs signal processing and subtraction on the first phase electric signal and the second phase electric signal. Interference of external light to the signal collection result can be effectively eliminated.

Description

 Optical image sensing system

 Technical field

 [0001] This solution belongs to the field of image sensing technology, and in particular, to an optical image sensing system.

 Background technique

 [0002] With the continuous development of science and technology, biometric image sensing technologies such as fingerprint recognition, facial recognition, vein recognition, and iris recognition are widely used in smart terminals such as mobile phones, check-in machines, door locks, etc., which improves the security of smart terminals. performance.

 technical problem

 [0003] The existing optical image sensing system is highly susceptible to interference from natural light or light emitted by the terminal itself when collecting the optical signal reflected by the object, thereby causing inaccurate acquisition results, thereby reducing the biometric recognition performance of the terminal.

 Problem solution

 Technical solution

 [0004] A first aspect of an embodiment of the present disclosure provides an optical image sensing system including a signal transmitting module, a signal receiving module, and a signal processing module;

 [0005] the signal transmitting module and the signal receiving module are electrically connected to the signal processing module;

 [0006] The signal transmitting module includes a light emitting source and a pulse frequency control unit, the pulse frequency control unit sends a pulse frequency control signal, and the light emitting source emits a periodic pulse light signal of a preset frequency according to the pulse frequency control signal. The pulsed optical signal of each period includes a first phase optical signal of a first intensity and a second phase optical signal of a second intensity; the signal receiving module receives the first phase optical signal reflected by the object and the first a two-phase optical signal, the first phase optical signal reflected by the object is processed into a first phase electrical signal, and the second phase optical signal reflected by the object is processed into a second phase electrical signal; the signal processing module Signal processing and subtraction are performed on the first phase electrical signal and the second phase electrical signal to obtain an effective electrical signal.

In one embodiment, the optical image sensing system further includes a filter disposed between the signal transmitting module and the signal receiving module; [0008] The filter filters the optical signal reflected by the object, and transmits the first phase optical signal and the second phase optical signal reflected by the object to the signal receiving module.

In one embodiment, the transmission band of the filter is the same as the wavelength range of the first phase optical signal and the second phase optical signal.

[0010] In one embodiment, the pulsed light signal comprises one or more of infrared light, ultraviolet light, or any visible colored light.

 [0011] In one embodiment, the illumination source comprises an LED lamp, a cold cathode fluorescent lamp or an array of LED lamps.

 [0012] In one embodiment, the signal receiving module includes at least one photosensitive element.

 [0013] In one embodiment, the signal processing module includes a signal amplifying unit and a logic operation unit;

[0014] the signal amplifying unit is electrically connected to the signal receiving module and the logic computing unit;

 [0015] the signal amplifying unit performs signal amplification on the first phase electrical signal and the second phase electrical signal

And the logic operation unit performs a subtraction operation on the amplified first phase electrical signal and the second phase electrical signal to obtain the effective electrical signal.

[0016] In an embodiment, the signal processing module further includes a filtering unit electrically connected to the signal amplifying unit and the logic operation unit, wherein the filtering unit pairs the amplified first phase electrical signal and The second phase electrical signal is filtered.

[0017] In one embodiment, the logic operation unit includes a sample and hold circuit including two first phase switches, two second phase switches, a first isolation device, and a second isolation device. [0018] the first isolation device is connected between the two first phase switches, and the second isolator is connected between the two second phase switches, wherein the first one is The phase switch and one of the second phases are connected to the signal amplifying unit, and the other of the second phase switches is connected to the other phase.

 [0019] In one embodiment, the optical image sensing system is applied to a display device, the display device including a backlight module, a display module, a display control module, a filter, the signal receiving module, and the signal Processing module

[0020] The backlight module includes the signal transmitting module, the light emitting source includes an infrared LED; the signal receiving module includes an array of photosensitive elements composed of a plurality of photosensitive elements, and an area of the signal receiving module is greater than or equal to The area of the display module, the signal receiving module is disposed above the display module Or the lower filter; the filter is an infrared filter that transmits infrared light; the display control module is electrically connected to the display module, and the display control module controls the infrared light to pass through the display module. Advantageous effects of the invention

 Beneficial effect

 [0021] The present scheme receives a first phase optical signal and a second phase optical signal reflected by an object by transmitting a periodic pulse optical signal including a first phase light signal of a first intensity and a second phase light signal of a second intensity. And processing the corresponding first phase electrical signal and the second phase electrical signal, and then subtracting the first phase electrical signal and the second phase electrical signal to cancel ambient light in the reflected signal or light emitted by the terminal itself , effectively eliminate the interference of external light on the signal acquisition results, to avoid misjudgment and misidentification.

 Brief description of the drawing

 DRAWINGS

 [0022] In order to more clearly illustrate the technical solutions in the embodiments of the present solution, the drawings used in the description of the embodiments will be briefly described below. Obviously, the drawings in the following description are some implementations of the present solution. For example, other drawings may be obtained from those of ordinary skill in the art in light of the inventive work.

1 is a schematic structural diagram of an optical image sensing system according to Embodiment 1 of the present application;

2 is a schematic diagram of a waveform of a periodic pulsed optical signal according to Embodiment 1 of the present embodiment;

3 is a schematic structural diagram of an optical image sensing system according to Embodiment 2 of the present embodiment;

4 is a schematic structural diagram of an optical image sensing system according to Embodiment 3 of the present embodiment;

5 is a schematic structural diagram of a display device according to Embodiment 4 of the present embodiment.

Embodiments of the invention

[0028] In the following description, for the purposes of illustration and description However, it will be apparent to those skilled in the art that the present invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details. Block the description of this program.

 [0029] In order to explain the technical solutions described in the present solution, the following description will be made by way of specific embodiments.

[0030] Embodiment 1:

 [0031] As shown in FIG. 1 , an embodiment of the present disclosure provides an optical image sensing system 100 including a signal transmitting module 10 , a signal receiving module 20 , and a signal processing module 30 . The signal transmitting module 10 includes a light source 1 . 1 and a pulse frequency control unit 12; wherein the signal transmitting module 10 and the signal receiving module 20 are electrically connected to the signal processing module 30. In this embodiment, the pulse frequency control unit is configured to emit a pulse frequency control signal, and the pulse frequency control signal is used to control the illumination source to emit a periodic pulsed optical signal of a preset frequency, and the pulse optical signal of each cycle includes the first intensity. a first phase optical signal and a second phase optical signal of a second intensity.

 [0032] In a specific application, the frequency of the pulsed optical signal can be set according to actual needs, and the higher the frequency of the pulsed optical signal, the faster the optical scanning speed of the optical image sensing system to the object, the first phase optical signal and the first The shorter the duration of the two-phase optical signal is.

[0033] In this embodiment, the first phase and the second phase are different, the first phase lags behind the second phase or the second phase lags behind the first phase, and two phases alternately appear in a plurality of cycles; There is one and only one first phase optical signal and one second phase optical signal.

[0034] In this embodiment, the first intensity and the second intensity are different, the first intensity is greater than the second intensity or the second intensity is greater than the first intensity, and the low intensity may be 0, that is, the signal transmitting module is lower in emission intensity The first phase optical signal or the second phase optical signal 吋 may not actually transmit a signal. Of course, the low intensity may not be zero.

 [0035] In a specific application, the pulse frequency control unit may specifically select a pulse frequency modulator or a chip, or may be a logic circuit having a corresponding function. As shown in FIG. 2, a waveform diagram showing a pulse light signal of a plurality of periods in which the first phase lags the second phase and the first intensity is greater than the second intensity 。 is exemplarily shown. In Fig. 2, PH1 represents the first phase, PH2 represents the second phase, and the height of the pulse represents the amplitude of the pulse, and the magnitude of the amplitude is proportional to the signal strength.

 [0036] In a specific application, the pulsed light signal can select an optical signal of any color or band according to actual needs. For example, when acquiring a fingerprint, a vein image, or an iris image, infrared light can be selected.

[0037] In one embodiment, the pulsed light signal comprises one of infrared light, ultraviolet light, or any visible colored light. Kind or more.

 [0038] In a specific application, the light source includes a luminaire for emitting one or more optical signals, and any type of luminaire can be selected according to actual needs, for example, an infrared LED lamp, an ultraviolet LED lamp, or the like.

 [0039] In one embodiment, the light source comprises an LED light, a cold cathode fluorescent light or an array of LED lights. When the illumination source includes an LED array, it can emit only one optical signal or a plurality of different types of optical signals.

 [0040] In this embodiment, the signal receiving module 20 receives the first phase optical signal and the second phase optical signal reflected by the object, and processes the first phase optical signal reflected by the object into the first phase electrical signal, and the object The reflected second phase optical signal is processed into a second phase electrical signal.

 [0041] In a specific application, the object may specifically be a biometric carrier such as a finger, a vein or an iris.

 [0042] In a particular application, the signal receiving module can include any device capable of optical signal acquisition and conversion into an electrical signal that can be processed by the signal processing module, such as a photosensitive element.

 [0043] In one embodiment, the signal receiving module includes at least one photosensitive element. When a plurality of photosensitive elements are included, a plurality of photosensitive elements may be arranged in an array to form an image sensor.

 [0044] In one embodiment, the photosensitive element is any one of a photodiode, a photoresistor, a charge coupled device, or a complementary metal oxide semiconductor.

 [0045] In this embodiment, the signal processing module is configured to perform signal processing and subtraction on the first phase electrical signal and the second phase electrical signal to obtain an effective electrical signal.

 [0046] In a specific application, the signal processing may specifically include conventional signal processing steps such as signal amplification, filtering, etc., and the signal is subtracted to cancel the environmental noise in the first phase electrical signal and the second phase electrical signal or the device itself. The noise part brought. In practical applications, since the first phase optical signal and the second optical signal reflected by the object are continuously collected, the interference factors of the environment or the device itself causing interference to the two signals are substantially the same, by using the two The subtraction of the electrical signal converted from the optical signal can substantially cancel out the interference caused by the interference factor, thereby obtaining a more accurate signal acquisition result, and by processing the finally obtained signal, a relatively accurate creature can be obtained. Feature images, which can provide recognition accuracy for biometrics.

[0047] In this embodiment, a first phase optical signal and a second phase optical signal reflected by an object are received by transmitting a periodic pulse optical signal including a first phase light signal of a first intensity and a second phase light signal of a second intensity. The number is processed into a corresponding first phase electrical signal and a second phase electrical signal, and then the first phase electrical signal and the second phase electrical signal are subtracted, which can cancel the ambient light in the reflected signal or the terminal itself Light, effectively eliminate the interference of external light on the signal acquisition results, to avoid misjudgment and misidentification.

 [0048] Embodiment 2:

 As shown in FIG. 3, in an embodiment of the present solution, the optical image sensing system 100 of the first embodiment further includes a filter 40 disposed between the signal transmitting module 10 and the signal receiving module 20.

 As shown in FIG. 3, in the embodiment, the illuminating source 11 is exemplarily shown as a light emitting diode, and the signal receiving module 20 is a photodiode. It should be understood that the LED and the photodiode in FIG. 3 are only a functional schematic, and it does not mean that the signal transmitting module and the signal receiving module must or only include the two devices. In practical applications, it may also include Other devices or equivalent devices are equivalently replaced.

 [0051] In this embodiment, the filter is configured to filter the optical signal reflected by the object, and transmit the first phase optical signal and the second phase optical signal reflected by the object to the signal receiving module.

 [0052] In a specific application, the function of the filter is to reflect or absorb the optical signal that is not needed by the signal receiving module, and to transmit the optical signal required by the signal receiving module. Specifically, a filter having a light transmission band equal to or closer to a wavelength range of the first phase light signal and the second phase light signal may be selected.

 [0053] In one embodiment, the transmission band of the filter is the same as the wavelength range of the first phase optical signal and the second phase optical signal. It should be understood that it is an ideal situation to select a filter having the same wavelength range as that of the first phase optical signal and the second phase optical signal, and it is difficult to achieve the same in practical applications, and only the wavelength bands can be selected as close as possible. of.

 As shown in FIG. 3, in the present embodiment, the signal processing module 30 includes a signal amplifying unit 31 and a logical operation unit 32; the signal amplifying unit 31 is electrically connected to the signal receiving module 20 and the logical operation unit 32.

[0055] In this embodiment, the signal amplifying unit is configured to perform signal amplification on the first phase electrical signal and the second phase electrical signal.

 [0056] In a specific application, the signal amplifying unit may specifically be a signal amplifier or a corresponding logic circuit.

[0057] In this embodiment, the logic operation unit is configured to perform subtraction on the amplified first phase electrical signal and the second phase electrical signal to obtain an effective electrical signal. [0058] In a specific application, the logic operation unit may specifically include a sample and hold circuit and a corresponding logic operation circuit.

 As shown in FIG. 3, in the embodiment, the signal processing module 30 further includes a filtering unit 33 electrically connected to the signal amplifying unit 31 and the logic computing unit 32, and the filtering unit 33 pairs the amplified first phase electrical signal. And filtering with the second phase electrical signal.

 [0060] In a specific application, the filtering unit may specifically include a filter circuit composed of a parallel filter capacitor and a resistor, or may be other types of filter circuits.

 [0061] Based on the structure of the optical image sensing system provided in this embodiment, in this embodiment, the calculation method of subtracting the amplified first phase electrical signal and the second phase electrical signal is as follows:

[0062] Let the amplification factor of the signal amplifying unit be A, the intensity of the reflected first phase optical signal during the first phase period phi is S1, the external optical interference amplitude is N_il, the device noise is N_cl, and the second phase ph2 The intensity of the second phase optical signal reflected during the period is S2, the amplitude of the external light interference is N_i2, the noise of the device is N_c 2, and the first phase electrical signal corresponding to the first phase optical signal reflected by the object is V_ol, and the second phase of the object reflection the second phase of the electrical signal to an optical signal is ¥ _ ₀ 2;

 [0063] Then the following relationship can be obtained:

 [0064] V_ol = A (Sl + N_il) + N_cl;

 [0065] V_o2=A(S2+N_i2) + N_c2;

 [0066] Subtracting the above equation, obtaining an effective electrical signal V_o2 - V_ol = A (S2 - SI + N_i2 - N_il) + N_c2 - N_cl;

 [0067] In practical applications, if an appropriate pulse frequency is used, N_i2 «N_il, N_c2 «N_cl, thereby obtaining an effective electrical signal V_o2 - V_ol=A(S2 - Sl).

 It can be seen from the above calculation results that the finally obtained effective signal substantially eliminates noise.

 [0069] Since the amplitude of the pulse is proportional to the signal strength, the signal strength is equivalent to the amplitude in the calculation.

 [0070] Embodiment 3:

[0071] As shown in FIG. 4, in an embodiment of the present invention, the logic operation unit 32 in the second embodiment includes a sample and hold circuit, and the sample and hold circuit includes two first phase switches PH1 and two second phases. PHPH2, first isolation device C1 and second isolation device C2; first isolation device C1 is connected to two first phases Between the PHIs, the second isolator PH2 is connected between the two second phase switches PH2, wherein one of the first phase switches and one of the second phase switches are connected to the signal amplifying unit 31, and the other second phase 幵Off and another phase is connected.

[0072] In a specific application, the four switches can be any type of electronic switch, such as a triode, a field effect transistor, etc., and the two isolation devices can also be any type of signal. The isolation device is not particularly limited in this embodiment.

[0073] It is exemplarily shown in FIG. 4 that all of the four switches are single pole single throws, and both isolation devices are capacitors.

[0074] FIG. 4 exemplarily shows that the signal amplifying unit 31 is a signal amplifier, and the filtering unit 33 includes a resistor R and a capacitor C3. The negative input terminal of the signal amplifier is connected to one end of the capacitor C3 and one end of the resistor R, and the signal amplifier The positive input terminal is connected to the reference signal VR, and the output end of the signal amplifier is connected to one of the first phase and one of the second phases.

[0075] Based on the structure provided by the embodiment, in a practical application, the pulse frequency control unit 13 emits a pulse current driving signal, and after driving the illumination source 11 to emit a first phase optical signal, the pulse current driving signal is a large current. The light source 11 emits strong light (specifically, infrared light);

[0076] when the driving light source 11 emits the second phase light signal 吋, the pulse current driving signal is a small current or no current, and the light source 11 emits weak light or does not emit light;

[0077] The filter 40 transmits an optical signal having a wavelength similar to that of the optical signal emitted by the illumination source 11;

[0078] The signal receiving module 20 receives the transmitted optical signal and converts it into a current signal;

 [0079] The operational amplification unit 32 amplifies the signal, the filtering unit 34 filters the signal and converts the current signal into a voltage signal; the capacitors C1 and C2 respectively amplify the signal in the first phase and the second phase Sampling;

 [0080] wherein, the voltage signal collected in the first phase phase corresponds to the signal amount of the strong light pupil is V1-VR, and the signal signal collected in the second phase phase corresponds to the signal amount of the weak light or the non-light emitting chirp is V2-VR;

 [0081] The effective signal V1-V2 can be obtained by subtracting the signal values of the above two samples, that is, obtaining an output voltage signal that can be finally processed into a biometric image.

[0082] Through the above signal processing method, if there is interference, the signal acquired in the first phase phase corresponds to the voltage signal of the strong light plus the interference 为 is Vl+Vn-VR, and the signal acquired in the second phase phase does not emit light or The voltage signal of weak light plus interference 为 is V2+Vn-VR, and the result after subtraction is still VI. -V2, therefore, the effects of interference will be eliminated.

Embodiment 4:

 As shown in FIG. 5, in one embodiment of the present scheme, the optical image sensing system 100 is applied to a display device.

1000. The display device 1000 includes a backlight module 200, a display module 300, a display control module 400, a filter 40, a signal receiving module 20, and a signal processing module 30.

As shown in FIG. 5, in the present embodiment, the signal transmitting module 10 belongs to a part of the backlight module 200.

[0086] In a specific application, the backlight module of the display device generally includes a backlight and a light homogenizing plate, and the backlight is usually a white LED disposed under or on the side of the light homogenizing plate. The signal transmitting module may specifically include an infrared LED lamp, and may also include other colors or types of lamps.

As shown in FIG. 5, the backlight module 200 further includes a light homogenizing plate 201 in this embodiment.

[0088] In a specific application, the signal receiving module specifically refers to a photosensitive component on an image sensor of a display device.

The signal receiving module is disposed above or below the display module. In the present embodiment, the signal receiving module is the image sensor itself, which includes a plurality of array-type photosensitive elements.

As shown in FIG. 5, in the embodiment, the signal receiving module 20 includes an array of photosensitive elements composed of a plurality of photosensitive elements, and the area of the signal receiving module 20 is greater than or equal to the area of the display module 300, and is disposed on the display. Above module 300.

 As shown in FIG. 5, in the present embodiment, the filter 40 is an infrared filter that transmits infrared light. In specific applications, it can also pass white light.

[0091] In one embodiment, the filter is an infrared trichromatic filter that transmits infrared, red, green, and blue light. It is prepared by a special coating process, which can transmit infrared light, red light, green light and blue light, so that the display module can display three primary color images as well as optical biological images such as fingerprints, veins and irises.

 As shown in FIG. 5, in the embodiment, the display control module 400 and the display module 300 are electrically connected, and the display control module 400 is configured to control the infrared light to pass through the display module 300.

[0093] In a specific application, the display module may be any type of display device, for example, a thin film transistor liquid crystal display (TFT-LCD, Thin Film Transistor-Liquid Crystal)

Display), OLED (Organic Electroluminescence Display) display, QLED (Quantum Dot Light Emitting Diodes) display, etc. . In this embodiment, the display module is specifically a thin film transistor liquid crystal display. Correspondingly, the display control module is specifically a TFT (Thin Film Transistor) liquid crystal driving chip. The display control module controls the display of the display module by adjusting the magnitude of the voltage applied to the display module and adjusting the optical axis orientation of the liquid crystal particles in the display module.

[0094] As shown in FIG. 5, the display device 1000 provided in this embodiment further includes a transparent cover 500, a transparent cover 50 0, a filter 40, a signal receiving module 20, a display module 300, a display control module 400, and The backlight module 20 0 is stacked in this order from top to bottom.

[0095] In a specific application, the transparent cover may specifically be a glass cover or a touch display panel.

[0096] The present embodiment provides a display device that combines a large-area image sensor and a display module, and does not require a capacitive touch signal acquisition device, and can realize a full-screen biological image acquisition function of the display device, and can be applied to a full-screen display device. It can improve the recognition accuracy of photobiometrics and avoid misjudgment and misrecognition.

 The above-mentioned embodiments are only used to explain the technical solutions of the present solution, and are not limited thereto; although the present solution has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: The technical solutions described in the foregoing embodiments are modified, or some of the technical features are equivalently replaced; and the modifications or substitutions do not deviate from the spirit and scope of the technical solutions of the embodiments of the present embodiments. It should be included in the scope of protection of this program.

Claims

Claim An optical image sensing system, comprising: a signal transmitting module, a signal receiving module and a signal processing module; The signal transmitting module and the signal receiving module are electrically connected to the signal processing module; the signal transmitting module includes a light emitting source and a pulse frequency control unit, and the pulse frequency control unit sends a pulse frequency control signal, the light source Transmitting a periodic pulsed optical signal of a preset frequency according to the pulse frequency control signal, wherein the pulsed optical signal of each period comprises a first phase optical signal of a first intensity and a second phase optical signal of a second intensity; Receiving, by the module, the first phase optical signal and the second phase optical signal reflected by the object, processing the first phase optical signal reflected by the object into a first phase electrical signal, and reflecting the object back The two-phase optical signal is processed into a second phase electrical signal; the signal processing module performs signal processing and subtraction on the first phase electrical signal and the second phase electrical signal to obtain an effective electrical signal. The optical image sensing system according to claim 1, wherein said optical image sensing system further comprises a filter disposed between said signal transmitting module and said signal receiving module; The filter filters an optical signal reflected by the object, and the first phase optical signal and the second phase optical signal reflected back from the object are transmitted to the signal receiving module. The optical image sensing system according to claim 2, wherein the transmission band of the filter has the same wavelength range as the first phase optical signal and the second phase optical signal. The optical image sensing system according to claim 1, wherein said pulsed optical signal comprises one or more of infrared light, ultraviolet light or any visible colored light. The optical image sensing system according to any one of claims 1 to 4, wherein the light source comprises an LED lamp, a cold cathode fluorescent lamp or an LED lamp array. The optical image sensing system according to claim 1, wherein said signal receiving module comprises at least one photosensitive element. The optical image sensing system according to claim 1, wherein said signal processing The module includes a signal amplifying unit and a logic operation unit;  The signal amplifying unit is electrically connected to the signal receiving module and the logic computing unit; the signal amplifying unit performs signal amplification on the first phase electrical signal and the second phase electrical signal, and the logical operation unit And decompressing the amplified first phase electrical signal and the second phase electrical signal to obtain the effective electrical signal. 8. The optical image sensing system according to claim 7, wherein the signal processing module further comprises a filtering unit electrically connected to the signal amplifying unit and the logic operation unit, the filtering The unit filters the amplified first phase electrical signal and the second phase electrical signal.  [Claim 9] The optical image sensing system according to claim 8, wherein the logic operation unit includes a sample and hold circuit, and the sample and hold circuit includes two first phase switches, two second Phase switching, first isolation device and second isolation device;  The first isolation device is connected between the two first phase switches, and the second isolator is connected between the two second phase switches, wherein the first phase is One of the second phase switches is connected to the signal amplifying unit, and the other of the second phase switches is connected to the other of the phases.  The optical image sensing system according to any one of claims 1 to 9, wherein the optical image sensing system is applied to a display device, and the display device comprises a backlight module and a display module. a display control module, a filter, the signal receiving module, and the signal processing module;  The backlight module includes the signal transmitting module, the light emitting source includes an infrared LED; the signal receiving module includes an array of photosensitive elements composed of a plurality of photosensitive elements, and an area of the signal receiving module is greater than or equal to the display. The area of the module, the signal receiving module is disposed above or below the display module; the filter is an infrared filter that transmits infrared light; and the display control module is electrically connected to the display module. The display control module controls the infrared light to pass through the display module.