CN209250731U

CN209250731U - Binary channels broad band intelligent CPE control device with interactive function and wireless communication function

Info

Publication number: CN209250731U
Application number: CN201821782806.0U
Authority: CN
Inventors: 葛宁; 谭令; 简锦超
Original assignee: Dongguan Huawei Electronic Co Ltd
Current assignee: Guangdong Huazhuang Technology Co.,Ltd.
Priority date: 2018-10-31
Filing date: 2018-10-31
Publication date: 2019-08-13
Anticipated expiration: 2028-10-31

Abstract

The utility model relates to a kind of binary channels broad band intelligent CPE control device with interactive function and wireless communication function, including human-computer interaction module, main control module, broadband communicating module, Intranet module and power management module, the human-computer interaction between interactive signal realization user and described device is inputted by the human-computer interaction module, completes the interactive process including the configuration of WIFI password.Using the binary channels broad band intelligent CPE control device with interactive function and wireless communication function in the utility model, the cable broadband module in conventional router is not only remained due to the broadband communicating module in CPE control device, the wireless communication module in existing CPE system is also taken into account, therefore compatibility with higher, moreover, the WEB page configuration port and telnet Telnet port of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function in the utility model are in closed state, therefore there is no third party devices to the malicious operation of the intelligent router of the utility model, improve safety.

Description

It is controlled with interactive function and the binary channels broad band intelligent CPE of wireless communication function Device

Technical field

The utility model relates to field of communication technology more particularly to interaction control technology field, in particular to one kind Binary channels broad band intelligent CPE control device with interactive function and wireless communication function.

Background technique

In the prior art, CPE generally only provides a kind of moveable broadband access network function by LTE cordless communication network Can, i.e., outer net only has mono- communication channel of LTE.The configuration mode of CPE usually can by the WEB pages of the terminals such as computer or TELNET Telnet is operated, and when taking first way, the terminals such as computer or mobile phone need to be used to be first coupled to the interior of CPE Net, and log on to the local area network WEB configuration page of CPE, WiFi title and password of cpe device etc. are carried out after password authentification The setting of various parameters item；It can also be remotely logged by TELNET on cpe device and the various parameters item of cpe device is carried out Configuration.

However, there is some potential safety problemss for above two mode of operation, it is likely to result in malicious person's CPE setting option Illegal modifications, be based on this, need CPE system a kind of new, that configuration hidden danger can be reduced.The cpe device of the utility model Outer net has two communication channels of LTE and cable network simultaneously, can connect LTE WiMAX and wired broadband network simultaneously, Network communication efficiency can be improved with concurrent communication, the communication load of automatic equalization LTE network and cable broadband improves internetworking Can, it can also be with the override mechanism of the customized outer net communication of user.And internal network part is in addition to having the wired network of traditional cpe device Except network interface and WiFi wireless network, it is also devised with pstn telephone machine interface, can connect common PSTN wire telephone, Speech telephony is realized by LTE module.To make the function of product and practicability obtain further raising.

Utility model content

The shortcomings that the purpose of the utility model is to overcome the above-mentioned prior arts, provides a kind of having for high safety performance The binary channels broad band intelligent CPE control device of interactive function and wireless communication function.

To achieve the goals above, the binary channels broadband intelligence with interactive function and wireless communication function of the utility model Energy CPE control device has following constitute:

The binary channels broad band intelligent CPE control device with interactive function and wireless communication function, is mainly characterized by, The device includes:

Human-computer interaction module, comprising:

Interactive voice submodule is connected with the main control module；

Basic input and output submodule, is connected with the main control module；

Main control module is connected with the human-computer interaction module；

Broadband communicating module is connected with the main control module, comprising:

Wireless telecommunications submodule is connected with the main control module；

Cable broadband submodule is connected with the main control module；

Intranet module is connected with the main control module；

Power management module is connected with the main control module；

The WEB page configuration port of described device and telnet Telnet port are in close state.

The interactive voice submodule of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function Block includes:

Voice receiving unit is connected with the main control module；

Voice broadcast unit, with the main control module number of being connected；

The speech output signal and the voice input signal are corresponding.

The basic input and output of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function Submodule includes:

Received text unit is connected with the main control module；

Screen display unit is connected with the main control module；

The text output signal and the text input signal are corresponding.

The Intranet module packet of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function It includes:

Switched telephone network submodule is connected with the main control module；

Cable network submodule is connected with the main control module；

Wireless network submodule is connected with the main control module.

The main control module of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function is super Low ultra low-power microcontroller.

The voice receiving unit of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function For microphone, the voice broadcast unit is loudspeaker.

The received text unit of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function For keyboard, the screen display unit is a liquid crystal display.

Using the binary channels broad band intelligent CPE control with interactive function and wireless communication function in the utility model Device realizes the man-machine friendship between user and CPE control device by interactive voice submodule and basic input and output submodule Mutually, above-mentioned interaction includes but is not limited to WAN mouthfuls of pattern switchings, the setting of broadband account, WIFI password/name modifications etc., while this Broadband communicating module in the CPE control device of utility model not only remains the cable broadband submodule in conventional router, The wireless telecommunications submodule in existing CPE system, compatibility with higher, moreover, in the utility model are also taken into account The binary channels broad band intelligent CPE control device with interactive function and wireless communication function WEB page configuration port and Telnet Telnet port is in closed state, therefore there is no third party devices to the intelligent router of the utility model Malicious modification operation, improve safety, have wider application range.

Detailed description of the invention

Fig. 1 is that the binary channels broad band intelligent CPE with interactive function and wireless communication function of the utility model controls dress The module connection structure schematic diagram set.

Fig. 2 is that the binary channels broad band intelligent CPE with interactive function and wireless communication function of the utility model controls dress The stereoscopic schematic diagram set.

Fig. 3 is that the binary channels broad band intelligent CPE with interactive function and wireless communication function of the utility model controls dress Another stereoscopic schematic diagram set.

Description of symbols:

1 WIFI antenna

2 LTE antennas

3 liquid crystal displays

4 switch keys

5 WIFI switch shortcut key

6 voices wake up shortcut key

7 householder mode shortcut keys

8 microphones

9 keyboards

10 lower covers

11 upper covers

12 WAN mouthfuls

13 LAN mouthfuls

14 loudspeakers

15 RJ11 interfaces

16 power interfaces

17 SIM card sockets

18 battery covers

19 large capacity chargeable batteries

20 battery compartments

Specific embodiment

In order to more clearly describe the technology contents of the utility model, carry out combined with specific embodiments below into one The description of step.

Refering to Figure 1, it is the binary channels broadband with interactive function and wireless communication function of the utility model The attachment structure schematic diagram of intelligent CPE control device, this has the binary channels broad band intelligent of interactive function and wireless communication function CPE control device includes:

Human-computer interaction module realizes the interaction between user and described device by input interactive signal；

Main control module is connected with the human-computer interaction module, for cooperating the human-computer interaction module to complete people Machine interactive process；

Broadband communicating module is connected with the main control module, for receiving and exchanging external broadband signal；

Intranet module is connected with the main control module, for providing wireless telephony services and network service；

Power management module is connected, for providing function of supplying power with the main control module；

The human-computer interaction module of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function Include:

Interactive voice submodule is connected with the main control module, passes through the voice input signal realization of user and institute State the human-computer interaction between device；

Basic input and output submodule, is connected with the main control module, passes through the text input signal of the user Realize the human-computer interaction between described device.

Voice receiving unit is connected with the main control module, for receiving the voice input signal；

Voice broadcast unit is connected with the main control module, for playing through the main control module treated language Sound output signal；

The speech output signal and the voice input signal are corresponding.

Received text unit is connected with the main control module, for receiving the text input signal；

Screen display unit is connected with the main control module, for show through the main control module treated text Word output signal；

The text output signal and the text input signal are corresponding.

Switched telephone network submodule is connected, for providing wireless telephony services with the main control module；

Cable network submodule is connected, for providing cable network with the main control module；

Wireless network submodule is connected, for providing wireless network with the main control module.

The broadband communicating module of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function Include:

Wireless telecommunications submodule, is connected with the main control module, is received by wireless telecommunications and exchanges external broadband Signal；

Cable broadband submodule, is connected with the main control module, is received by wire communication and exchanges external broadband Signal.

I.e. the utility model belongs to the pattern of fusion product that cable broadband router is combined with LTE wireless router, has Two broadband channels (binary channels CPE): one is cable broadband channel, connects broadband network by the WAN mouth 12 of product；It is another A is wireless 2 broadband channel LTE, and the wireless broadband network of operator is connected by built-in LTE data communication module.Default shape State broadband channel is set as auto state, and product detects the connection of cable broadband automatically, if there is line width band connection is normal Then product is surfed the Internet by cable broadband；If detecting that cable broadband connection is unsuccessful, and detect that Intranet has legitimate device to have In the case where the communication need of connected reference broadband network, then wireless broadband network is connected using LTE data communication module immediately, Ensure that user can satisfy the broadband access network use demand of user；

If broadband channel is selected as cable broadband channel pattern, remains and connect broadband using cable broadband channel Network.If detecting that cable broadband connection is unsuccessful, and detect that Intranet has legitimate device to have connected reference broadband network In the case where communication need, then remind user that " cable broadband connection failure please check broadband network or be switched to voice mode LTE wireless broadband network channel ", and automatic cycle reconnects wired broadband network, until cable broadband successful connection.Such as Fruit user is switched to LTE wireless broadband network according to the prompt on voice or screen, then is no longer attempt to connection cable broadband network Network；

If broadband channel is selected as LTE WiMAX channel pattern, remains and connected using LTE WiMAX channel Connect broadband network.If detecting that the connection of LTE WiMAX is unsuccessful, and detect that Intranet has legitimate device to have connected reference wide In the case where communication need with network, then remind user that " LTE WiMAX connection failure please be attempted to switch with voice mode To wired broadband network channel ", and automatic cycle reconnects LTE broadband network, until LTE WiMAX successful connection. If user is switched to wired broadband network according to the text prompt in voice prompting or screen, it is no longer attempt to connection LTE Wireless broadband network.

In a specific embodiment, it please refers to shown in Fig. 2 and Fig. 3, the utility model has interactive function and wireless Broadband communicating module in the binary channels broad band intelligent CPE control device of call function has binary channels, the key packet in keyboard It includes but is not limited to WIFI switch shortcut key 5, voice wakes up shortcut key 6, householder mode shortcut key 7 etc., and is provided with 3 LAN mouthfuls 13 and 1 WAN mouths 12, each LAN mouth 13 and WAN mouth 12 can be respectively configured as 100-M network Ethernet or gigabit network interface；WIFI Network design is 2.4G and 5.8G double frequency, supports 802.11b/g/n/ac, WIFI is wireless, and network speed can achieve 2,000,000,000 or more.

The binary channels broad band intelligent CPE control device with interactive function and wireless communication function of the utility model can be with External telephone set has voice call function:

The binary channels broad band intelligent CPE control device setting with interactive function and wireless communication function of the utility model There is a RJ11 interface 15, can connect common pstn telephone machine.The RJ11 interface connects LTE by SLIC module and communicates mould Block, so that realize that pstn telephone machine is realized by LTE module carries out voice by function between other phones, user can lead to It crosses and is connected to the pstn telephone machine of the RJ11 interface 15 and dials other phones and carry out voice communication, the SLIC when there is phone incoming call Module can export bell signal to telephone set, and ringing telephone stations wait user to answer；User can also directly pass through phonetic order Product automatic dialing is allowed to call other phones, equipment is directly logical in the case where the telephone set that user connects without using RJ11 mouth 15 It crosses LTE module and dials the number for needing to call, the Mike and loudspeaker that default is carried using equipment carry out hand-free call；It is being set Off-hook during off-hook or calling and call before the standby phonetic order made a phone call, the then hand-free call of pass hull closure itself immediately State is switched to Telephone handset talking state.

The binary channels broad band intelligent CPE control device with interactive function and wireless communication function of the utility model has both Screen and keyboard man-machine interaction mode:

It is provided with liquid crystal display and keyboard, is realized by keyboard and liquid crystal display and the parameter of router is configured, Conventional router class product generallys use the mode that the WEB page of router is configured that logs in.The product of the utility model WEB page configures port and telnet Telnet port and all closes inside this product, is connected to the inside of this product The network equipment and remote network equipment can not all modify to any parameter setting, it is ensured that the safety of network configuration.

The screen and keyboard man-machine interactive interface mode carried by product, does not need by means of computer, mobile phone, PAD etc. Any third party device logs in the software WEB configuration page of product or completes the various parameters setting of equipment by APP.Directly " broadband account and the password, WIFI of equipment can quickly and easily be completed very much by connecting screen menu options and keyboard operation The configuration of the multiple parameters such as title and password, MAC Address binding ".It is accessed accordingly after the completion of configuration according to actual disposition situation Broadband network, connection, WIFI network state, the operating mode of equipment, network time of broadband network etc. are all directly setting Standby screen is shown that the current working condition of equipment is very clear.Main human-computer interaction content is as follows:

One, host parameter configures:

1, WAN mouthfuls of pattern switchings (WAN mouthfuls of the broadband PPPOE dialing, three kinds of DHCP, static IP efforts modes choosings It selects)；

2, broadband account is arranged；

3, dial-up connection password in broadband is arranged；

4, WIFI title is modified；

5, WIFI password is modified；

6, binding MAC address；(network terminal when executing this function in router meeting automatically scanning WIFI coverage area, The MAC Address list of the network equipment scanned is shown after the completion of scanning on the screen, and is prompted with voice mode with selection The equipment for needing to bind, then user confirms with voice mode or presses that the determination key of keyboard completes interdependent equipment and router MAC Address binding relationship.To make can not access the WIFI network of this router with the equipment of router binding)；

7, release MAC Address binding (MAC that can release some equipment and router is bound, can also release it is all with The equipment that router had been bound)；

8, setting is closed in WIFI hot spot time opening and timing；

9, WIFI channel control (automatic, switching designated channel)；

10, operating mode switching (route pattern, wired ap mode, wireless relay mode)；

11, broadband channel setting (automatic, cable broadband, LTE WiMAX)；

12, the hiding and display of SSID (under SSID hidden state, the network of wireless network card is had using mobile phone, computer etc. Equipment scans the WiFi network less than CPE, only knows that the talent of WiFi network title and password can be using addition nothing manually The mode of gauze network inputs WiFi title and correct WiFi password in the equipment such as mobile phone could access the WiFi net of the CPE Network effectively prevent illegality equipment to access).

Two, following function can also be completed by the menu or shortcut key of product in product use process:

1, CPE shuts down (MCU enters sleep state, other all modular circuit power-off shutdowns)；

2, CPE starting up (MCU voice wakes up or keyboard boot, MCU control other modular circuit electrifying startups)；

3, WIFI network is opened；

4, WIFI network is closed；

5, parent's pipe diameter design is enabled (to be under long pipe diameter design, parent's mobile phone of connection this product WIFI has highest Permission, the equipment progress Website login limitation of other accesses this product WIFI, surf time can be limited by parent's mobile phone, A variety of settings such as Games Software limitation, the limitation of shopping online software, instant message applications limitation, to control on children's health Net)；

6, parent's pipe diameter design is closed.

The binary channels broad band intelligent CPE control device with interactive function and wireless communication function of the utility model has Intelligent sound human-computer interaction function:

It is provided with microphone 8 and loudspeaker 14, there is intelligent sound identification function and voice broadcast function, to realize Product parameters based on voice mode human-computer interaction configure and using controls.Interactive voice configuration feature is opened by shortcut key, When by after password Authority Verification, keyboard can not be used, following configuration is directly completed by utterance；And it is operating When the phonetic order of personnel is incorrect or does not know, this product can provide corresponding voice prompting, with nan-machine interrogation's interaction Mode instruct the user how using.Voice broadcast function can be " interruption-free mode " by menu setting, not need in user " voice interruption-free mode " can be enabled in the case where various voice reminders.

In a specific embodiment, the binary channels broadband with interactive function and wireless communication function of the utility model Main intelligent sound human-computer interaction content in intelligent CPE control device is as follows:

One, host parameter configures:

1, WAN mouthfuls of pattern switchings (WAN mouthfuls of the dialing of the broadband PPPOE, three kinds of DHCP, static IP efforts model selections)

2, broadband account is arranged

3, dial-up connection password in broadband is arranged

4, WIFI title is modified；

5, WIFI password is modified；

6, binding MAC address；(network terminal when executing this function in router meeting automatically scanning WIFI coverage area, The MAC Address list of the network equipment scanned is shown after the completion of scanning on the screen, and is prompted with voice mode with selection The equipment for needing to bind, then user confirms with voice mode or presses that the determination key of keyboard completes interdependent equipment and router MAC Address binding relationship.To be the WIFI network that can not do not access this router with the equipment of router binding)

8, setting is closed in WIFI hot spot time opening and timing；

9, WIFI channel control (automatic, switching designated channel)

10, operating mode switching (route pattern, wired ap mode, wireless relay mode)

11, broadband channel setting (automatic, cable broadband, LTE WiMAX).

12, the hiding and display of SSID (under SSID hidden state, the network of wireless network card is had using mobile phone, computer etc. Equipment scans the WiFi network less than CPE, only knows that the talent of WiFi network title and password can be using addition nothing manually The mode of gauze network inputs WiFi title and correct WiFi password in the equipment such as mobile phone could access the WiFi net of the CPE Network effectively prevent illegality equipment to access.)

Two, following function can also be completed by phonetic order in product use process:

3, WIFI network is opened

4, WIFI network is closed

5, parent's pipe diameter design is enabled (to be under long pipe diameter design, parent's mobile phone of connection this product WIFI has highest Permission, the equipment progress Website login limitation of other accesses this product WIFI, surf time can be limited by parent's mobile phone, A variety of settings such as Games Software limitation, the limitation of shopping online software, instant message applications limitation, to control on children's health Net)

6, parent's pipe diameter design is closed.

Preferably, the binary channels broad band intelligent CPE control with interactive function and wireless communication function of the utility model Device has both interactive voice operating function and on-screen keyboard interactive function, and the process of human-computer interaction is realized by intelligent sound mode In, the phonetic order of product identification user of service and when executing corresponding movement, screen can the corresponding menu operation of simultaneous display Content, i.e., effective phonetic order function are equal to corresponding menu and keyboard operation instruction.Make each operating procedure so more It is clear to add, if speech recognition input is wrong, directly can find mistake by screen and be corrected by keyboard.This Sample interactive voice mode and menu and the interactive mode of keyboard operation combine, and two ways can be used concurrently, be cooperated, Make the use mode of operation of product it is simpler, conveniently, flexibly, practicability it is stronger.

Such as user allows product to modify WIFI password, product identification to corresponding phonetic order using interactive voice mode Afterwards, screen shows the new WIFI password that user needs to be modified as automatically, and rests on password typing state.User exists at this time It can see the new password that the plaintext of modification is shown on screen, and whether correct with voice mode inquiry operator's password. If password is correct, user can be answered correctly with voice mode, or click directly on corresponding determination key on keyboard, then completed The modification of WIFI password, returns to standby mode.If the new password of equipment speech recognition is wrong, user can be directly current Interface is modified by keyboard, and then user is answered correct with voice mode, or clicks directly on corresponding determination on keyboard Key then completes the modification of WIFI password.

The use pattern that interactive voice mode of operation is combined with on-screen keyboard interactive operation mode, makes each operating procedure Become it is simpler, clear, conveniently, flexibly, it is practical, be network communication product using a major transformation of mode of operation and change Into.

In a specific embodiment, the power management module of the utility model is filled equipped with 20000 milliampere hour large capacities Battery is powered in the case where external power supply access product to product by external power supply and product is maintained to work normally, simultaneously It is charged the battery by power management module；In the case that external power supply disconnects or has a power failure, switch to battery power supply, dimension automatically It holds product to continue to work normally, and short message is sent to the phone of user by LTE module and is reminded, inform that product external power supply is disconnected Electricity.

In the case where battery is fully charged, battery can generally maintain equipment that it is more than hour to work on 20 when power failure. When using battery, if there is the legal network equipment need to access network then according to demand suitably starting cable broadband or The outer net channel of LTE WiMAX, and start WIFI network or Intranet wireline interface according to demand, it is unnecessary to reduce to the greatest extent Electric quantity consumption.Dynamic rationally closes relevant Internet resources when not having network communication requirement, to reduce to battery electricity The consumption of amount.The main consumption such as network communication module and LTE module is automatically closed if 10 minutes without any network communication Electric part, MCU enter the sleep state of super low-power consumption, but at any time can be fast by phonetic order or keyboard that Mike receives Prompt key wake-up device starts corresponding Internet resources, guarantees online communication need.The utility model under super low-power consumption mode to The machine time can be more than 3 months or more, and the broadband network communication function of equipment can be very square at any time in this time range Just it wakes up and uses.To make the practicability of equipment increase substantially.

The skill of the binary channels broad band intelligent CPE control device with interactive function and wireless communication function of the utility model In art scheme, wherein included each functional module and modular unit can be corresponding to specific hard in integrated circuit structure Part circuit, therefore the improvement of particular hardware circuit is only related to, hardware components not only only belong to execute control software or calculating The carrier of machine program, therefore solve corresponding technical problem and obtain corresponding technical effect to be also not directed to any control software Or the application of computer program, that is to say, that the utility model is just with the electricity of hardware involved in these modules and unit Improvement in terms of line structure can solve technical problem to be solved, and obtain corresponding technical effect, and not need Corresponding function can be thus achieved specifically to control software or computer program in auxiliary.

Using the binary channels broad band intelligent CPE control with interactive function and wireless communication function in the utility model Device realizes the interaction between user and CPE control device by interactive voice submodule and basic input and output submodule, on Stating interaction includes but is not limited to WAN mouthfuls of pattern switchings, the setting of broadband account, WIFI password/name modifications etc., while this is practical new Broadband communicating module in the CPE control device of type not only remains the cable broadband submodule in conventional router, also takes into account Wireless telecommunications submodule in existing CPE system, compatibility with higher, moreover, having in the utility model The WEB page of interactive function and the binary channels broad band intelligent CPE control device of wireless communication function configures port and telnet is remote Journey login-port is in closed state, therefore repairs there is no third party device to the malice of the intelligent router of the utility model Change operation, improve safety, there is wider application range.

In this description, the utility model is described with reference to its specific embodiment.But it is clear that still can be with The spirit and scope that various modification can be adapted and converts without departing from the utility model.Therefore, the description and the appended drawings should be considered as It is illustrative and not restrictive.

Claims

1. a kind of binary channels broad band intelligent CPE control device with interactive function and wireless communication function, which is characterized in that institute The device stated includes:

Human-computer interaction module, comprising:

Interactive voice submodule, is connected with main control module；

Basic input and output submodule, is connected with the main control module；

Main control module is connected with the human-computer interaction module；

Cable broadband submodule is connected with the main control module；

Intranet module is connected with the main control module；

Power management module is connected with the main control module；

2. the binary channels broad band intelligent CPE according to claim 1 with interactive function and wireless communication function controls dress It sets, which is characterized in that the interactive voice submodule includes:

Voice receiving unit is connected, for receiving voice input signal with the main control module；

Voice broadcast unit, and the main control module number of being connected, for playing through the main control module treated voice Output signal；

The speech output signal and the voice input signal are corresponding.

3. the binary channels broad band intelligent CPE according to claim 1 with interactive function and wireless communication function controls dress It sets, which is characterized in that the basic input and output submodule includes:

Received text unit is connected with the main control module；

Screen display unit is connected with the main control module；

The text output signal and the text input signal are corresponding.

4. the binary channels broad band intelligent CPE according to claim 1 with interactive function and wireless communication function controls dress It sets, which is characterized in that the Intranet module includes:

Cable network submodule is connected with the main control module；

Wireless network submodule is connected with the main control module.

5. the binary channels broad band intelligent CPE according to claim 1 with interactive function and wireless communication function controls dress It sets, which is characterized in that the main control module is ultralow micropower single-chip microcontroller.

6. the binary channels broad band intelligent CPE according to claim 2 with interactive function and wireless communication function controls dress It sets, which is characterized in that the voice receiving unit is microphone, and the voice broadcast unit is loudspeaker.

7. the binary channels broad band intelligent CPE according to claim 3 with interactive function and wireless communication function controls dress It sets, which is characterized in that the received text unit is keyboard, and the screen display unit is a liquid crystal display.