CN101210846B

CN101210846B - Ambient light sensor circuit and flat panel display device having the same

Info

Publication number: CN101210846B
Application number: CN2007103022089A
Authority: CN
Inventors: 权五敬
Original assignee: Hanyang Hak Won Co Ltd
Current assignee: Hanyang Hak Won Co Ltd
Priority date: 2006-12-27
Filing date: 2007-12-17
Publication date: 2011-06-29
Anticipated expiration: 2027-12-17
Also published as: KR100825411B1; CN101210846A

Abstract

Disclosed are an ambient light sensor circuit and a flat panel display device having the same that can automatically control screen brightness by sensing ambient brightness and controlling an output current. The ambient light sensor circuit comprises: a transistor electrically coupled to a first power source; a first capacitive element electrically coupled between a control electrode of the transistor and a first reference power source; a second capacitive element electrically coupled between the first capacitive element and a second reference power source; a first light receiving element electrically coupled between the first and third reference power sources and controlling a coupling voltage of the first capacitive element and charge/discharge voltages of the second capacitive element by conducting current in response to ambient light; a first switch electrically coupled to the transistor and enabling the transistor to output current from the first power source according to the coupling voltage of the first capacitive element; and a second switch electrically coupled between the first light receiving element and the first capacitive element and interrupting a leakage current of the first light receiving element, thereby preventing the coupling voltage of the first capacitive element from being changed.

Description

Ambient light sensor circuit and flat panel display equipment with this circuit

Priority request

The application is based on the korean patent application No.10-2006-0135376 that submitted to Korea S Department of Intellectual Property (KIPO) on Dec 27th, 2006 and submitted to the korean patent application No.10-2007-0080754 of Korea S Department of Intellectual Property on August 10th, 2007, and requiring the right of priority of these two patented claims, its full content is incorporated herein by reference.

Technical field

The present invention relates to a kind of ambient light sensor circuit and have the flat panel display equipment of this circuit, relate more specifically to a kind of can by sensitive context brightness and control output current automatically the brightness of control flow curtain the ambient light sensor circuit and have the flat panel display equipment of this circuit.

Background technology

Usually, flat panel display equipment comprises organic electro-luminescence display device, liquid crystal display, plasma display panel device and field-emission display device.Flat panel display equipment is because thin, in light weight and low in energy consumption and replaced traditional CRT (cathode-ray tube (CRT), Cathode Ray Tube) display device rapidly.Organic electro-luminescence display device and liquid crystal display can manufacture little size like a cork, and can use for a long time under the situation of using battery, therefore are widely used as the display device of portable electric appts.

Flat panel display equipment such as organic electro-luminescence display device or liquid crystal display can come its brightness of manual control by user's operation.Yet it is designed to always not consider ambient brightness with constant brightness display screen.For example, the user feels that screen is brighter relatively in the room that ambient brightness does not work, but feels that in the sun screen is darker relatively, therefore has visual problem.

In addition, the brightness of traditional flat panel display equipment is set to aforesaid constant level, therefore because when it uses in dark relatively place for a long time its brightness do not need so high, so the problem that exists power consumption to increase.

In addition, when for sensitive context brightness in traditional flat panel display equipment during the manufacturing environment optical sensor circuit, should on the separate substrates that is different from the main substrate that forms two-d display panel, form sensor, substrate and circuit, and be connected to mainboard, thereby the size of flat panel display equipment, thickness and power consumption increase.

In addition, the output current of the ambient light sensor circuit of classic flat-plate display device changes between sampling period owing to light leakage current, so the ambient light sensor circuit can not be sampled to surround lighting exactly.

In addition, the output current of the ambient light sensor circuit of classic flat-plate display device according to the increase of environment temperature because the temperature leakage current changes so ambient light sensor circuit sense ambient light exactly.

Summary of the invention

Therefore, an object of the present invention is to provide a kind of ambient light sensor circuit and flat panel display equipment with this circuit, it can and control output current and control the screen intensity of flat panel display equipment automatically according to ambient brightness by sensitive context brightness, to improve the visuality in bright place and dark place.

Another object of the present invention provides a kind of ambient light sensor circuit and has the flat panel display equipment of this circuit, and it can keep optimal power by controlling power consumption automatically according to ambient brightness, thereby prolongs the life-span of portable flat panel display equipment.

Another purpose of the present invention provides a kind of ambient light sensor circuit and has the flat panel display equipment of this circuit, it can pass through to form ambient light sensor circuit, surround lighting processor, time schedule controller, data driver, scanner driver and light emitting control driver on the same substrate that forms organic electroluminescence panel (or liquid crystal panel), thereby prevents from unnecessarily to increase the size and the thickness of flat panel display equipment.

In addition, another purpose of the present invention provides a kind of ambient light sensor circuit and has the flat panel display equipment of this circuit, it can be by carrying out between sampling period interrupting the light leakage current that applies from light receiving element and preventing that light leakage current from changing output current to surround lighting, thereby exactly surround lighting is sampled.

In addition, another purpose of the present invention provides a kind of ambient light sensor circuit and has the flat panel display equipment of this circuit, and it can prevent that the temperature leakage current from changing the output current of ambient light sensor circuit according to the increase of environment temperature.

To be partly articulated additional advantage of the present invention, purpose and feature in the following description, by to the research of following content or to the study of practice of the present invention, additional advantage of the present invention, purpose and feature will partly become clear to those skilled in the art.

According to an aspect of the present invention, provide a kind of ambient light sensor circuit, it comprises: transistor, and it comprises first electrode that is electrically coupled to first power supply; First capacitive element, it comprises first electrode that is electrically coupled to transistorized control electrode and second electrode that is electrically coupled to first reference power supply; Second capacitive element, second electrode that it comprises first electrode of second electrode that is electrically coupled to first capacitive element and is electrically coupled to second reference power supply; First light receiving element, its electric coupling between the first and the 3rd reference power supply, and by in response to surround lighting conduction current control the charging of the coupled voltages and second capacitive element of first capacitive element; First switch, it is electrically coupled to transistorized second electrode, and makes that transistor can be according to the electric current of the coupled voltages of first capacitive element output from first power supply; Second switch, its electric coupling and interrupt the leakage current of first light receiving element between first light receiving element and first capacitive element, thereby the coupled voltages that prevents first capacitive element is changed; The 3rd switch, electric coupling make first reference voltage is applied to first and second capacitive elements from first reference power supply via second switch between first reference power supply and second switch; The 4th switch, electric coupling and make transistor can form the diode syndeton between the transistorized control electrode and first switch; The 5th switch, electric coupling make via first switch reference current to be applied to transistor, thereby predetermined voltage are applied to transistorized control electrode between first switch and reference current source; The 6th switch is electrically coupled to first switch, and makes transistor scheduled current to be sent to output terminal from first power supply via first switch in response to the coupled voltages of first and second capacitive elements; The 3rd capacitive element, the 3rd capacitive element is electrically coupled to second capacitive element, and increases the reverse bias ability of first light receiving element; And the minion pass, this minion is closed electric coupling between the second and the 3rd capacitive element, makes them be electrically coupled to one another.

First light receiving element is any one that select from p-intrinsic-n (p-i-n) diode, p-intrinsic-metal (p-i-m) diode, p-n diode and photoelectrical coupler, the anode of first light receiving element is electrically coupled to first reference power supply, and cathodic electricity is coupled to the 3rd reference power supply.

The 3rd reference voltage that applies from the 3rd reference power supply is higher than first reference voltage that applies from first reference power supply.

First light receiving element is any one that select from p-intrinsic-n (p-i-n) diode, p-intrinsic-metal (p-i-m) diode, p-n diode and photoelectrical coupler, the cathodic electricity of first light receiving element is coupled to first reference power supply, and anode is electrically coupled to the 3rd reference power supply.

The 3rd reference voltage that applies from the 3rd reference power supply is lower than first reference voltage that applies from first reference power supply.

The second light receiving element electric coupling and comprises light shield layer between first light receiving element and the 4th reference power supply because the surround lighting crested, therefore second light receiving element only sensing depend on the leakage current of the increase of temperature.

The temperature sensor senses temperature; Look-up table is electrically coupled to temperature sensor, and storage is corresponding to the surround lighting sensing time of the temperature that senses; And controller is electrically coupled to look-up table, and first control signal offered first switch in response to the surround lighting sensing time from look-up table output.

The first and second electrode electric coupling of first switching transistor are between first and second capacitive elements, and its control electrode is electrically coupled to the second negative control signal; And transistorized first and second electrodes of second switch are electrically coupled to transistorized control electrode, and its control electrode is electrically coupled to the 3rd negative control signal.

The 4th and each switch in the minion Central Shanxi Plain form by two transistors that are connected in series.

According to an aspect of the present invention, provide a kind of flat panel display equipment, it comprises: the ambient light sensor circuit, and this circuit comprises: transistor, it comprises first electrode that is electrically coupled to first power supply; First capacitive element, its electric coupling is between the transistorized control electrode and first reference power supply; Second capacitive element, it comprises first electrode that is electrically coupled to first capacitive element and second electrode that is electrically coupled to second reference power supply; First light receiving element, its electric coupling between first reference power supply and the 3rd reference power supply, and by in response to surround lighting conduction current control the charging of the coupled voltages and second capacitive element of first capacitive element; First switch, it is electrically coupled to transistorized second electrode, and makes that transistor can be according to the electric current of the coupled voltages of first capacitive element output from first power supply; And second switch, its electric coupling and is interrupted the leakage current of first light receiving element between first light receiving element and first capacitive element, thus the coupled voltages that prevents first capacitive element is changed; The surround lighting processor controls, it receives analog output signal from the ambient light sensor circuit as input signal, and calculates current environment light and it is exported as digital value; Time schedule controller, it receives output signal from the surround lighting processor controls as input signal, and output is corresponding to the control signal of current environment light; And organic electroluminescence panel, it receives the control signal corresponding to current environment light that applies from time schedule controller, and to send light corresponding to the brightness of current environment light.Wherein the ambient light sensor circuit also comprises the 3rd switch, and the 3rd switch electric coupling makes first reference voltage is applied to first and second capacitive elements from first reference power supply via second switch between first reference power supply and second switch; The ambient light sensor circuit also comprises the 4th switch, and the 4th switch electric coupling and makes transistor can form the diode syndeton between the transistorized control electrode and first switch; The ambient light sensor circuit also comprises the 5th switch, and the 5th switch electric coupling makes via first switch reference current to be applied to transistor, thereby predetermined voltage is applied to transistorized control electrode between first switch and reference current source; The ambient light sensor circuit also comprises the 6th switch, and the 6th switch is electrically coupled to first switch, and makes transistor scheduled current to be sent to output terminal from first power supply via first switch in response to the coupled voltages of first and second capacitive elements; The ambient light sensor circuit also comprises the 3rd capacitive element, and the 3rd capacitive element is electrically coupled to second capacitive element, and increases the reverse bias ability of first light receiving element; And the ambient light sensor circuit comprises that also minion closes, and this minion is closed electric coupling between the second and the 3rd capacitive element, makes them be electrically coupled to one another.

Time schedule controller comprises: look-up table, and its storage is corresponding to the data of current environment brightness; And the brightness selector switch, it will compare with the data that are stored in the look-up table from the data of surround lighting processor controls input, and selects to output to data driver corresponding to the data controlling signal of current environment brightness and with it.

Data driver receives output signal from time schedule controller as input signal, and output is applied to organic electroluminescence panel corresponding to the data-signal of current environment brightness and with it.

The light emitting control driver receives output signal from time schedule controller as input signal, and output led control signal and it is applied to organic electroluminescence panel.

Power-supply controller of electric receives output signal from time schedule controller as input signal, and output is applied to organic electroluminescence panel corresponding to the supply voltage of current environment light and with it.

According to an aspect of the present invention, provide a kind of flat panel display equipment, it comprises: the ambient light sensor circuit, and this circuit comprises: transistor, it comprises first electrode that is electrically coupled to first power supply; First capacitive element, its electric coupling is between the transistorized control electrode and first reference power supply; Second capacitive element, it comprises first electrode that is electrically coupled to first capacitive element and second electrode that is electrically coupled to second reference power supply; First light receiving element, its electric coupling between the first and the 3rd reference power supply, and by in response to surround lighting conduction current control the charging of the coupled voltages and second capacitive element of first capacitive element; First switch, it is electrically coupled to transistorized second electrode, and makes that transistor can be according to the electric current of the coupled voltages of first capacitive element output from first power supply; And second switch, its electric coupling and is interrupted the leakage current of first light receiving element between first light receiving element and first capacitive element, thus the coupled voltages that prevents first capacitive element is changed; The surround lighting processor controls, it receives analog output signal from the ambient light sensor circuit as input signal, and calculates current environment light and it is exported as digital value; Time schedule controller, it receives output signal from the surround lighting processor controls as input signal, and output is corresponding to the control signal of current environment light; Inverter, it receives output signal from time schedule controller as input signal, and supply voltage is brought up to corresponding to the level of current environment light and with its output; Backlight, it comes on/off by the voltage that applies from inverter; And display panels, it comes display screen by backlight; Wherein the ambient light sensor circuit also comprises the 3rd switch, and the 3rd switch electric coupling makes first reference voltage is applied to first and second capacitive elements from first reference power supply via second switch between first reference power supply and second switch; The ambient light sensor circuit also comprises the 4th switch, and the 4th switch electric coupling and makes transistor can form the diode syndeton between the transistorized control electrode and first switch; The ambient light sensor circuit also comprises the 5th switch, and the 5th switch electric coupling makes via first switch reference current to be applied to transistor, thereby predetermined voltage is applied to transistorized control electrode between first switch and reference current source; The ambient light sensor circuit also comprises the 6th switch, the 6th switch is electrically coupled to described first switch, and makes transistor scheduled current to be sent to output terminal from first power supply via first switch in response to the coupled voltages of first and second capacitive elements; The ambient light sensor circuit also comprises the 3rd capacitive element, and the 3rd capacitive element is electrically coupled to second capacitive element, and increases the reverse bias ability of first light receiving element; And the ambient light sensor circuit comprises that also minion closes, and this minion is closed electric coupling between the second and the 3rd capacitive element, makes them be electrically coupled to one another.

Description of drawings

From the detailed description of carrying out below in conjunction with accompanying drawing, above and other purpose of the present invention, feature and advantage will be more apparent, in the accompanying drawings:

Fig. 1 a is the circuit diagram that illustrates according to the ambient light sensor circuit of the flat panel display equipment of one exemplary embodiment of the present invention to 1c;

Fig. 2 is the sequential chart of the ambient light sensor circuit of flat panel display equipment;

Fig. 3 is the circuit diagram that illustrates according to the ambient light sensor circuit of the flat panel display equipment of another exemplary embodiment of the present invention;

Fig. 4 is the circuit diagram that the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention is shown;

Fig. 5 is the circuit diagram that the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention is shown;

Fig. 6 is the circuit diagram that the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention is shown;

Fig. 7 is the circuit diagram that the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention is shown;

Fig. 8 is the characteristic curve of look-up table of ambient light sensor circuit that the flat panel display equipment of Fig. 7 is shown;

Fig. 9 is the circuit diagram that the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention is shown;

Figure 10 illustrates the block diagram that the surround lighting processor controls further is connected to the state of ambient light sensor circuit;

Figure 11 is the block diagram that the structure of the flat panel display equipment with ambient light sensor circuit in accordance with a further exemplary embodiment of the present invention is shown;

Figure 12 a is the circuit diagram of an example of image element circuit that the organic electroluminescence panel of flat panel display equipment is shown, and Figure 12 b is the sequential chart of image element circuit;

Figure 13 a is the block diagram that the structure of the flat panel display equipment with ambient light sensor circuit in accordance with a further exemplary embodiment of the present invention is shown, and Figure 13 b is the sequential chart of this equipment;

Figure 14 a is the block diagram that the structure of the flat panel display equipment with ambient light sensor circuit in accordance with a further exemplary embodiment of the present invention is shown, and Figure 14 b is the sequential chart of this equipment;

Figure 15 is the block diagram that the structure of the flat panel display equipment with ambient light sensor circuit in accordance with a further exemplary embodiment of the present invention is shown; And

Figure 16 is the block diagram that is shown specifically an example of inverter shown in Figure 15 (inverter).

Embodiment

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings.By consulting the embodiment that is described in detail with reference to the attached drawings, various aspects of the present invention and feature and be used to realize that the method for these aspects and feature becomes clear.Yet, the invention is not restricted to hereinafter disclosed embodiment, can realize the present invention with various forms.The content that limits in the instructions such as detailed structure and element, is that the detail that is provided is comprehensively understood the present invention to help those skilled in the art, only limits the present invention within the scope of the appended claims.In whole instructions of the present invention, Reference numeral identical between each figure is used for components identical.In addition, term " electric coupling " not only means " directly coupling ", also means " getting involved the element coupling by other ".

Fig. 1 a illustrates circuit diagram according to the ambient light sensor circuit of the flat panel display equipment of one exemplary embodiment of the present invention to 1c.

With reference to figure 1a, the ambient light sensor circuit of flat panel display equipment comprises transistor Tr 1, the first capacitive element C1, the second capacitive element C2, the 3rd capacitive element C3, the first light receiving element PD1, first switch S 1, second switch S2, the 3rd switch S 3, the 4th switch S 4, the 5th switch S 5, the 6th switch S 6 and minion pass S7.At this, the second reference power supply V _REF2With the 3rd reference power supply V _REF3Can be electrically coupled to VDD and receive first voltage, thereby can similarly operate at the ambient light sensor circuit of the flat panel display equipment of Fig. 1.Identical Reference numeral is used for each reference power supply and reference voltage so that below describe.In other words, the identical Reference numeral first reference power supply V _REF1Be used for first power supply and first reference voltage, the second reference power supply V _REF2Be used for the second source and second reference voltage, and the 3rd reference power supply V _REF3Be used for the 3rd power supply and the 3rd reference voltage.

Transistor Tr 1 comprises first electrode (source electrode or drain electrode), second electrode (drain electrode or source electrode) and control electrode (grid).First electrode of transistor Tr 1 is electrically coupled to VDD, the second electrode electric coupling is between second electrode of first electrode of first switch S 1 and the 4th switch S 4, and the control electrode electric coupling is between second electrode of first electrode of the 4th switch S 4 and the first capacitive element C1.Transistor Tr 1 is a p channel transistor, can be any one that select from amorphous silicon transistor, polycrystalline SiTFT, OTFT, nano thin-film transistor and equivalent thereof, but is not limited thereto.

In addition, when transistor Tr 1 was polycrystalline SiTFT, it can form by a kind of method of selecting from laser crystallization method, crystallization inducing metal method, high pressure crystal method and equivalent thereof, but is not limited thereto.

The laser crystallization method is by to the amorphous silicon radiation excimer laser method of carrying out crystallization for example, the crystallization inducing metal method is by metal for example being set on amorphous silicon and heating the method for coming to begin from metal crystallization with predetermined temperature, and the high pressure crystal method is to carry out method for crystallising by for example apply predetermined pressure to amorphous silicon.

First electrode of the first capacitive element C1 is electrically coupled to second electrode of second electrode, second switch S2 of the second capacitive element C2 and the first node N1 between second electrode that minion is closed S7.Second electrode of the first capacitive element C1 is electrically coupled between first electrode of control electrode and the 4th switch S 4.First capacitive element C1 storage produces coupled voltages with the second capacitive element C2, and it is applied to the control electrode of transistor Tr 1 corresponding to the voltage of the voltage difference between first and second electrodes of the first capacitive element C1.

First electrode of the second capacitive element C2 is electrically coupled to the second reference power supply V _REF2, second electrode of the second capacitive element C2 is electrically coupled to second electrode of first electrode, second switch S2 of the first capacitive element C1 and the first node N1 between second electrode that minion is closed S7.Second capacitive element C2 storage produces coupled voltages with the first capacitive element C1, and it is applied to the control electrode of transistor Tr 1 corresponding to the voltage of the voltage difference between first and second electrodes of the second capacitive element C2.In addition, the second capacitive element C2 improves the signal retention performance by the reverse bias ability that increases the first light receiving element PD1.

First electrode of the 3rd capacitive element C3 is electrically coupled to the second reference power supply V _REF2, second electrode of the 3rd capacitive element C3 is electrically coupled to first electrode that minion is closed S7.The 3rd capacitive element C3 storage improves the signal retention performance corresponding to the voltage of the voltage difference between first and second electrodes of the 3rd capacitive element C3 by the reverse bias ability that increases the first light receiving element PD1.

The anode electric coupling of the first light receiving element PD1 is between second electrode of first electrode of second switch S2 and the 3rd switch S 3, and the cathodic electricity of the first light receiving element PD1 is coupled to the 3rd reference power supply V _REF3At this, when first electrode of the 3rd switch S 3 is electrically coupled to first reference voltage V _REF1And when connecting the 3rd switch S 3, it is with the first reference power supply V _REF1Be applied to the anode of the first light receiving element PD1, the first reference power supply V _REF1Can be to be lower than the 3rd reference power supply V _REF3Level.In addition, the first light receiving element PD1 can be from p-intrinsic-n (p-i-n, p-intrinsic-n) (p-i-m, p-intrinsic-metal) any one that select in diode, p-n diode, photo-coupler and the equivalent thereof still are not limited thereto for diode, p-intrinsic-metal.The first light receiving element PD1 is by applying in response to surround lighting from the 3rd reference power supply V _REF3Electric current come charging to the first capacitive element C1 and the second capacitive element C2.

The first electrode electric coupling of first switch S 1 is between second electrode of second electrode of transistor Tr 1 and the 4th switch S 4, and second electrode of first switch S 1 is electrically coupled to Section Point N2, and N2 is the contact point between the 5th switch S 5 and the 6th switch S 6.Can come on/off first switch S 1 by first control signal that control electrode is applied.Can form first switch S 1 by any one that from N raceway groove or P raceway groove low temperature polycrystalline silicon and equivalent thereof, select, but be not limited thereto.First switch S 1 is initialized as predetermined voltage with the first capacitive element C1, and perhaps the coupled voltages in response to the first capacitive element C1 and the second capacitive element C2 will output to output terminal I via the scheduled current amount that transistor Tr 1 is applied by VDD _OUT

The first electrode electric coupling of second switch S2 is between second electrode of the anode of the first light receiving element PD1 and the 3rd switch S 3, and the second electrode electric coupling of second switch S2 is between second electrode of first electrode of the first capacitive element C1 and the second capacitive element C2.Can be by the second control signal on/off second switch S2 that control electrode is applied.Can form second switch S2 by any one that from N raceway groove or P raceway groove low temperature polycrystalline silicon and equivalent thereof, select, but be not limited thereto.When second switch S2 disconnected, the light leakage current that is applied to the first light receiving element PD1 of the first and second capacitive element C1 and C2 was interrupted, thereby the coupled voltages that prevents the first capacitive element C1 and the second capacitive element C2 changes.

First electrode of the 3rd switch S 3 is electrically coupled to the first reference power supply V _REF1, the second electrode electric coupling of the 3rd switch S 3 is between first electrode of the anode of the first light receiving element PD1 and second switch S2.Can be by the 3rd control signal on/off the 3rd switch S 3 that control electrode is applied.Can form the 3rd switch S 3 by any one that from N raceway groove or P raceway groove low temperature polycrystalline silicon and equivalent thereof, select, but be not limited thereto.When the 3rd switch S 3 is connected, be applied to the first reference power supply V of first electrode _REF1Be sent to the first capacitive element C1 and the second capacitive element C2.

The first electrode electric coupling of the 4th switch S 4 is between second electrode of the control electrode of transistor Tr 1 and the first capacitive element C1, and the second electrode electric coupling of the 4th switch S 4 is between first electrode of second electrode of transistor Tr 1 and first switch S 1.Can be by the 3rd control signal on/off the 4th switch S 4 that control electrode is applied.Can form the 4th switch S 4 by any one that from N raceway groove or P raceway groove low temperature polycrystalline silicon and equivalent thereof, select, but be not limited thereto.When the 4th switch S 4 was connected, transistor Tr 1 formed the diode syndeton.

First electrode of the 5th switch S 5 is electrically coupled to the Section Point N2 between first electrode of second electrode of first switch S 1 and the 6th switch S 6, and second electrode of the 5th switch S 5 is electrically coupled to reference current source I _REFCan be by the 4th control signal on/off the 5th switch S 5 that control electrode is applied.Can form the 5th switch S 5 by any one that from N raceway groove or P raceway groove low temperature polycrystalline silicon and equivalent thereof, select, but be not limited thereto.When the 5th switch S 5 is connected, will be from reference current source I _REFThe reference current that applies is applied to transistor Tr 1 via first switch S 1.At this moment, transistor Tr 1 forms the diode syndeton.As the first reference power supply V _REF1When being applied to first node N1, the coupled voltages of the first capacitive element C1 and the second capacitive element C2 remains unchanged.

First electrode of the 6th switch S 6 is electrically coupled to the Section Point N2 between first electrode of second electrode of first switch S 1 and the 5th switch S 5, and second electrode of the 6th switch S 6 is electrically coupled to output terminal I _OUTCan be by the 5th control signal on/off the 6th switch S 6 that control electrode is applied.Can form the 6th switch S 6 by any one that from N raceway groove or P raceway groove low temperature polycrystalline silicon and equivalent thereof, select, but be not limited thereto.When the 4th switch S 4 was connected, transistor Tr 1 formed the diode syndeton.The 6th switch S 6 will output to output terminal I via the scheduled current amount that transistor Tr 1 applies from VDD in response to the coupled voltages of the first capacitive element C1 and the second capacitive element C2 _OUT

First electrode that minion is closed S7 is electrically coupled to second electrode of the 3rd capacitive element C3, and minion is closed the second electrode electric coupling of S7 between second electrode of first electrode of second electrode of second switch S2, the first capacitive element C1 and the second capacitive element C2.Can close S7 by the 6th control signal on/off minion that control electrode is applied.Can form minion by any one that from N raceway groove or P raceway groove low temperature polycrystalline silicon and equivalent thereof, select and close S7, but be not limited thereto.When a large amount of light of unexpected incident and the S7 connection of minion pass, the 3rd capacitive element C3 and the second capacitive element C2 are connected in parallel with each other, and the reverse bias ability of the light receiving element PD1 that wins is increased, thereby improve the signal retention performance.

With reference to figure 1b, except switch S 1 to S7 was formed by p channel transistor, the ambient light sensor circuit of flat panel display equipment was identical with the ambient light sensor circuit of Fig. 1 a.

With reference to figure 1c, close S7 forms by two p channel transistors except switch S 2 and S4 and minion, the ambient light sensor circuit of flat panel display equipment is identical with the ambient light sensor circuit of Fig. 1 b.When second switch S2, the 4th switch S 4 and minion were closed the S7 disconnection, the voltage of the grid of first node N1 and transistor Tr 1 was flow through the influence of the leakage current of each switch.Therefore, can form the leakage current that switch reduces switch by the transistor that is connected in series by two, thus the phenomenon that the compensation leakage current changes the voltage of first node N1 and transistor Tr 1 grid.

Fig. 2 a and 2b illustrate the sequential chart of ambient light sensor circuit of the flat panel display equipment of Fig. 1 a to 1c.Fig. 2 a illustrates the sequential chart under the situation that switch S 1 to S7 is a p channel transistor, and Fig. 2 b illustrates the sequential chart under the situation that switch S 1 to S7 is the N channel transistor.Except when switch S 1 to S7 switch is connected at the low level place when being p channel transistor, switch is beyond the high level place connects when switch S 1 to S7 is the N channel transistor, the sequential chart of Fig. 2 a and 2b is mutually the same.Therefore, the sequential chart of main key diagram 2a below.

With reference to figure 2a and 2b, the sequential chart of the ambient light sensor circuit of flat panel display equipment comprises initialization time section T1, surround lighting sensing time period T2 and sampling time section T3.With five control signals is the ambient light sensor circuit that first control signal, second control signal, the 3rd control signal, the 4th control signal and the 5th control signal are applied to flat panel display equipment.

In addition, relatively very bright and therefore a large amount of light time of incident is applied to the ambient light sensor circuit with the 6th control signal when surround lighting.Omit the sequential chart of the 6th control signal, but described the 6th control signal is closed S7 to minion operation below in detail.

At first, in initialization time section T1, when low level first to fourth control signal is applied to the ambient light sensor circuit of flat panel display equipment, first switch S 1, second switch S2, the 3rd switch S 3, the 4th switch S 4 and the 5th switch S 5 are connected, when applying the 5th control signal of high level, the 6th switch S 6 disconnects.

When the 5th switch S 5 is connected, reference current source I _REFReference current be sent to first switch S 1, when first switch S 1 was connected, reference current was sent to second electrode of transistor Tr 1.At this moment, when the 4th switch S 4 was connected, transistor Tr 1 formed the diode syndeton.Because transistor Tr 1 forms the diode syndeton and reference current is applied to second electrode consistently, remain on constant voltage V so be applied to the voltage of the control electrode of transistor Tr 1 _A

When the 3rd switch S 3 is connected, from the first reference power supply V _REF1First reference voltage that applies is sent to the second switch S2 and the first light receiving element PD1, and when second switch S2 connected, this reference voltage was sent to first node N1.This reference voltage that is applied to first node N1 is sent to the first capacitive element C1 and the second capacitive element C2.

First capacitive element C1 storage and the first reference power supply V that is applied to first electrode of the first capacitive element C1 _REF1Voltage V with the control electrode of the transistor Tr 1 that is applied to second electrode _ABetween the corresponding voltage of difference.Second capacitive element C2 storage and the second reference power supply V that is applied to first electrode of the second capacitive element C2 _REF2With the first reference power supply V that is applied to second electrode _REF1Between the corresponding voltage of difference.In other words, when applying the first reference power supply V with steady state value _REF1, the second reference power supply V _REF2With reference current source I _REFThe time, the voltage that is stored among the first capacitive element C1 and the second capacitive element C2 is initialized as steady state value.

Next, in surround lighting sensing time period T2, when applying low level second control signal, second switch S2 connects.When applying the first, the 3rd, the 4th and the 5th control signal of high level, first switch S 1, the 3rd switch S 3, the 4th switch S 4, the 5th switch S 5 and the 6th switch S 6 disconnect.

When second switch S2 connected, the inverse current that forms between first electrode of the first light receiving element PD1 and second electrode was applied to the first node N1 as the contact point of the first capacitive element C1 and the second capacitive element C2.At this, the inverse current that forms by the first light receiving element PD1 is according to the brightness of surround lighting and difference.In other words, when the surround lighting deepening, flow through the electric current step-down of the first light receiving element PD1, when surround lighting brightened, the electric current that flows through the first light receiving element PD1 uprised.

When the inverse current that forms by the first light receiving element PD1 is applied to first node N1 as the contact point of the first capacitive element C1 and the second capacitive element C2, the voltage of first node N1 corresponding to inverse current from the first reference power supply V _REF1Change voltage Δ V, therefore become V _REF1+ Δ V.At this moment, the first reference power supply V _REF1Be the voltage that in initialization time section T1, is applied to first node N1.

According to the change of the voltage of first node N1, the voltage of second electrode of the first capacitive element C1 and the storage voltage of the second capacitive element C2 change corresponding to the variation voltage of first node N1.In other words, the voltage of first node N1 has changed Δ V corresponding to the inverse current that forms by the first light receiving element PD1, be stored in voltage among the second capacitive element C2 and changed Δ V corresponding to the variation voltage Δ V of first node N1 and charge, the voltage that is stored among the first capacitive element C1 remains unchanged.Thereby, the change in voltage of second electrode of the first capacitive element C1 Δ V.Therefore, the coupled voltages of the first capacitive element C1 changes corresponding to the variation voltage of first node N1.

At this, when surround lighting is bright relatively, the second capacitive element C2 is charged rapidly, but when surround lighting is dark relatively, the second capacitive element C2 is slowly charged.

At last, in sampling time section T3, when applying the low level first and the 5th control signal, first switch S 1 and the 6th switch S 6 are connected.When applying second, third and the 4th control signal of high level, second switch S2, the 3rd switch S 3, the 4th switch S 4 and the 5th switch S 5 disconnect.

When first switch S 1 was connected, the electric current that applies from transistor Tr 1 outputed to output terminal I via the 6th switch S 6 _OUTAt this moment, transistor Tr 1 via the 6th switch S 6 will with the corresponding electric current I of coupled voltages of the first capacitive element C1 and the second capacitive element C2 _REF-Δ I outputs to output terminal I _OUTIn other words, the coupled voltages with the first capacitive element C1 and the second capacitive element C2 is applied to control electrode.When this coupled voltages was low, big relatively electric current outputed to output terminal I via transistor Tr 1 _OUTWhen coupled voltages was high, relatively little electric current outputed to output terminal I via transistor Tr 1 _OUT

At this, Δ I is the current change quantity that will flow through the electric current variation of transistor Tr 1 in the time will being applied to first node N1 with the corresponding voltage variety Δ of the inverse current V that forms by the first light receiving element PD1.The coupled voltages of the first capacitive element C1 and the second capacitive element C2 becomes the voltage of the control electrode of transistor Tr 1.Therefore, when this coupled voltages was low, Δ I diminished, and when this coupled voltages was high, it is big that Δ I becomes.

As mentioned above, when weak relatively light incided the first light receiving element PD1, the electrorheological that flows through the first light receiving element PD1 got relatively little, and therefore, the coupled voltages of the first capacitive element C1 and the second capacitive element C2 becomes relative little.So, flow through the electric current I of transistor Tr 1 _REFIt is big relatively that-Δ I becomes naturally.On the other hand, when strong relatively light incided the first light receiving element PD1, the electrorheological that flows through the first light receiving element PD1 got big relatively, and therefore, the coupled voltages of the first capacitive element C1 and the second capacitive element C2 becomes relative big.So, flow through the electric current I of transistor Tr 1 _REFIt is relatively little that-Δ I becomes naturally.

When second switch S2 disconnected, the first light receiving element PD1 separated from first node N1.The light leakage current that the reaction of the first light receiving element PD1 and surround lighting is produced in sampling time section T3 is applied to first node N1, thereby the coupled voltages that prevents the first capacitive element C1 and the second capacitive element C2 changes.

On the other hand, the following describes of the operation of the 6th control signal to the 3rd capacitive element C3.When light incides the first light receiving element PD1 suddenly, to the second capacitive element C2 rapid charge.At this moment, first node N1 promptly second electrode of the second capacitive element C2 be charged to the 3rd reference power supply V _REF3In other words, when sensing surround lighting when brighter, from transistor Tr 1 output constant output electric current than predetermined luminance.Therefore, sense ambient light exactly.

In order to prevent above-mentioned phenomenon, connect circuit by applying low level the 6th control signal, the 6th control signal is as output terminal I _OUTOutput current to remain on threshold value following and continue the feedback signal of the schedule time.So the 3rd capacitive element C3 and the second capacitive element C2 are connected in parallel.

Therefore, the second capacitive element C2 and the 3rd capacitive element C3 are connected in parallel with each other, thereby the electric capacity of capacitor increases.Therefore, the reverse bias ability of the first light receiving element PD1 further increases.Certainly, the second capacitive element C2 and the 3rd capacitive element C3 influence coupled voltages with the first capacitive element C1, and consequently, coupled voltages influences the operation of transistor Tr 1.Therefore, therefore operate transistor Tr1 in reliable running time section obtains stable output voltage.That is, the 3rd capacitive element C3 and the second capacitive element C2 are connected in parallel, thereby first light receiving element PD1 sense ambient light more easily.

Fig. 3 illustrates the circuit diagram according to the ambient light sensor circuit of the flat panel display equipment of another exemplary embodiment of the present invention.

With reference to figure 3, except the negative electrode of the first light receiving element PD1 is connected on the contrary with anode, in other words, cathodic electricity is coupling between second electrode of first electrode of second switch S2 and the 3rd switch S 3, and anode is electrically coupled to the 3rd reference power supply V _REF3In addition, the ambient light sensor circuit of flat panel display equipment is similar to the ambient light sensor circuit shown in Fig. 1 a.At this moment, first electrode of the 3rd switch S 3 is electrically coupled to the first reference power supply V _REF1, when the 3rd switch S 3 is connected, the first reference power supply V _REF1Be applied to the negative electrode of the first light receiving element PD1.At this, the first reference power supply V _REF1Can be higher than the 3rd reference power supply V _REF3Therefore, in the ambient light sensor circuit of Fig. 1 a, to second capacitive element C2 charging, the coupled voltages of the first capacitive element C1 increases according to the increase of flowing through the inverse current of the first light receiving element PD1.Yet, in the ambient light sensor circuit of Fig. 3, second capacitive element C2 discharge, the coupled voltages of the first capacitive element C1 reduces according to the increase of flowing through the inverse current of the first light receiving element PD1.

Fig. 4 illustrates the circuit diagram of the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention.

With reference to figure 4, except transistor Tr 2 was formed by the N channel transistor, the ambient light sensor circuit of flat panel display equipment was similar to the ambient light sensor circuit shown in Fig. 1 a.In the ambient light sensor circuit of Fig. 1 a, first switch S 1, the 4th switch S 4, the 5th switch S 5 and the 6th switch S 6 are electrically coupled to second electrode of transistor Tr 1.In the ambient light sensor circuit of Fig. 4, transistor Tr 2 is N channel transistors, thereby first switch S 1, the 4th switch S 4, the 5th switch S 5 and the 6th switch S 6 are electrically coupled to first electrode.Except replacing p channel transistor use N channel transistor, the ambient light sensor circuit of flat panel display equipment shown in Figure 4 is similar to the ambient light sensor circuit of Fig. 1 a, thereby the operation of this ambient light sensor circuit identical with described in Fig. 1 a, 2a and the 2b.

Fig. 5 illustrates the circuit diagram of the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention.

With reference to figure 5, except the negative electrode of the first light receiving element PD1 is connected on the contrary with anode, in other words, cathodic electricity is coupling between second electrode of first electrode of second switch S2 and the 3rd switch S 3, and anode is electrically coupled to the 3rd reference power supply V _REF3In addition, the ambient light sensor circuit of this flat panel display equipment is similar to ambient light sensor circuit shown in Figure 4.At this moment, first electrode of the 3rd switch S 3 is electrically coupled to the first reference power supply V _REF1, when the 3rd switch connection, the first reference power supply V _REF1Be applied to the negative electrode of the first light receiving element PD1.At this, the first reference power supply V _REF1Can be higher than the 3rd reference power supply V _REF3Therefore, in the ambient light sensor circuit of Fig. 4, to second capacitive element C2 charging, the coupled voltages of the first capacitive element C1 increases according to the increase of flowing through the inverse current of the first light receiving element PD1.Yet, in the ambient light sensor circuit of Fig. 5, second capacitive element C2 discharge, the coupled voltages of the first capacitive element C1 reduces according to the increase of flowing through the inverse current of the first light receiving element PD1.

Fig. 6 illustrates the circuit diagram of the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention.

With reference to figure 6, except the ambient light sensor circuit also comprises the negative electrode that is electrically coupled to the first light receiving element PD1 and comprises that the second light receiving element PD2 of shadow shield, the ambient light sensor circuit of this flat panel display equipment is similar to the ambient light sensor circuit shown in Fig. 1 a.The cathodic electricity of the second light receiving element PD2 is coupled to the anode of the first light receiving element PD1, and the anode of the second light receiving element PD2 is electrically coupled to V _REF4At this, the first reference power supply V _REF1Can be than the 3rd reference power supply V _REF3Low level, V _REF4Can be than the first reference power supply V _REF1Low level.

When surround lighting incided the first light receiving element PD1, the first light receiving element PD1 conducted from the 3rd reference power supply V in response to surround lighting _REF3Electric current, make to change the coupled voltages of the first capacitive element C1 and the second capacitive element C2 charged.At this moment, the electric current that flows through the first light receiving element PD1 increases according to the increase of temperature.In other words, produced leakage current.The second light receiving element PD2 comprises shadow shield, thereby is similar to the first light receiving element PD1, and the electric current that flows through the second light receiving element PD2 changes according to the increase of temperature.Yet the incident surround lighting does not cause that electric current changes.Therefore, flow through the electric current of the first light receiving element PD1 and the difference that flows through between the electric current of the second light receiving element PD2 is by the caused electric current of surround lighting, thereby can be applied to first node N1 corresponding to the voltage of this difference between current.Thereby, can prevent to change output current by the caused leakage current of temperature.The first light receiving element PD1 and the second light receiving element PD2 are the light receiving elements with identical characteristics, and have identical temperature characterisitic.

In other words, the electric current that flows through the first light receiving element PD1 is the electric current I that the increase by temperature causes _DarkWith in response to surround lighting from the 3rd reference power supply V _REF3Electric current I _PhotoAnd.Because the second light receiving element PD2 comprises shadow shield, only comprise that temperature increases caused electric current I so flow through the electric current of the second light receiving element PD2 _DarkTherefore, flow through the electric current of the first light receiving element PD1 and the difference that flows through between the electric current of the second light receiving element PD2 becomes from the 3rd reference power supply V _REF3I _PhotoTherefore, have only that the temperature change of not being subjected to influences by the caused electric current I of surround lighting _PhotoFlow through the ambient light sensor circuit via second switch S2, thereby removed the leakage current that causes by temperature, thereby prevented the change of output current.

The ambient light sensor circuit of Fig. 3 to Fig. 5 removes the leakage current that is caused by temperature by further comprising the second light receiving element PD2 with shadow shield, thereby can prevent the change of output current.

Fig. 7 illustrates the circuit diagram of the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention.

With reference to figure 7, except the ambient light sensor circuit of this flat panel display equipment comprises that further beyond temperature sensor, look-up table (LUT, look up table) and the controller, this ambient light sensor circuit is similar to the ambient light sensor circuit shown in Fig. 1 a.

Temperature sensor is electrically coupled to the temperature of look-up table (LUT) and sensitive context optical sensor circuit, sends sensed temperature to look-up table.

Look-up table (LUT) electric coupling is between temperature sensor and controller, so that will be sent to controller corresponding to the surround lighting sensing time of sensed temperature.At this, look-up table (LUT) is the storer of storing corresponding to the surround lighting sensing time of sensed temperature, and Fig. 8 shows the characteristic curve of look-up table.

The controller electric coupling is between first to the 6th control signal and look-up table (LUT).Look-up table (LUT) output is corresponding to surround lighting sensing time of sensed temperature and send it to controller, and the surround lighting sensing time that will depend on temperature is applied to first to the 6th control signal.At this moment, when temperature raise, leakage current increased, thereby surround lighting sensing time decreased.When temperature reduces, do not produce leakage current, thereby compare with the high situation of temperature, the surround lighting sensing time increases.Therefore, by transistor Tr 1 from output terminal I _OUTThe electric current of output remains unchanged.

The ambient light sensor circuit of Fig. 3 to Fig. 5 comes the surround lighting sensing time of control response in the leakage current that is caused by temperature by further comprising temperature sensor, look-up table (LUT) and controller, thereby can prevent the change of output current.

Fig. 8 is the characteristic curve of look-up table of ambient light sensor circuit that the flat panel display equipment of Fig. 7 is shown.

With reference to the characteristic curve of figure 8, the leakage current of light receiving element increases according to the increase of the sensing temperature that is applied by temperature sensor.The increase of surround lighting sensing time according to leakage current increases.When the sensing temperature that is applied by temperature sensor increased, the leakage current of light receiving element increased, thus surround lighting sensing time decreased.Voltage is applied to the time decreased of the first node N1 between the first capacitive element C1 and the second capacitive element C2 from the first light receiving element PD1, thereby reduce the duration of charging of the first capacitive element C1 and the second capacitive element C2.In other words, can prevent from output terminal I with the electric current increase that compensation is caused by temperature by reducing the surround lighting sensing time _OUTThe change of the output current of output.

Fig. 9 illustrates the circuit diagram of the ambient light sensor circuit of flat panel display equipment in accordance with a further exemplary embodiment of the present invention.

With reference to figure 9, except the ambient light sensor circuit of flat panel display equipment further comprised the first switching transistor ST1 and second switch transistor ST2, this ambient light sensor circuit was similar to the ambient light sensor circuit shown in Fig. 1 a.

The first switching transistor ST1 comprises first electrode (source electrode or drain electrode), second electrode (drain electrode or source electrode) and control electrode (grid).First electrode of the first switching transistor ST1 and second electrode are electrically coupled to the first node N1 between the first capacitive element C1 and the second capacitive element C2.Can make first switching transistor ST1 conducting or the shutoff by the second negative control signal that is applied to control electrode.At this, the second negative control signal is the signal opposite with second control signal.When second control signal was high level, the second negative control signal was a low level, and when second control signal was low level, the second negative control signal was a high level.

As shown in Figure 9, p channel transistor can be used as the first switching transistor ST1.At this moment, p channel transistor is also as second switch S2.When the first switching transistor ST1 conducting, second switch S2 disconnects, and when the first switching transistor ST1 turn-offed, second switch S2 connected.In other words, the first switching transistor ST1 and second switch S2 reciprocally work.The first switching transistor ST1 can be the N channel transistor.At this moment, second switch S2 should also be the N channel transistor.

When the surround lighting sensing time period T2 that disconnects from the first switching transistor ST1 conducting and second switch S2 when the time period changed to sampling time section T3, the switch mistake when disconnecting owing to second switch S2 produced the phenomenon that output current reduces according to the voltage increase of the control electrode of transistor Tr 1.The first switching transistor ST1 can compensate this phenomenon.

Second switch transistor ST2 comprises first electrode (source electrode or drain electrode), second electrode (drain electrode or source electrode) and control electrode (grid).First electrode of second switch transistor ST2 and second electrode are electrically coupled to the control electrode of transistor Tr 1.Can make second switch transistor ST2 conducting/shutoff by the 3rd negative control signal that is applied to control electrode.At this, the 3rd negative control signal is the signal opposite with the 3rd control signal.When the 3rd control signal was high level, the 3rd negative control signal was a low level, and when the 3rd control signal was low level, the 3rd negative control signal was a high level.

As shown in Figure 9, p channel transistor can be used as second switch transistor ST2.At this moment, p channel transistor is also as the 4th switch S 4.When second switch transistor ST2 conducting, the 4th switch S 4 disconnects, and when second switch transistor ST2 turn-offed, the 4th switch S 4 was connected.In other words, second switch transistor ST2 and the 4th switch S 4 are reciprocally worked.Second switch transistor ST2 can be the N channel transistor.At this moment, the 4th switch S 4 should also be the N channel transistor.

When the initialization time section T1 that disconnects from the ST2 conducting of second switch transistor and the 4th switch S 4 when the time period changes to surround lighting sensing time period T2, because the switch mistake during 4 disconnections of the 4th switch S produces the phenomenon that output current reduces according to the increase of the voltage of the control electrode of transistor Tr 1.Connect virtual switch (dummy switch) the i.e. first switching transistor ST1, thereby compensate this phenomenon.

The ambient light sensor circuit of Fig. 3 to Fig. 5 by further comprising the first switching transistor ST1 and second switch transistor ST2 and can compensating output current because switch mistake and the phenomenon that reduces that increases according to the voltage of transistorized control electrode.

Figure 10 illustrates the block diagram that the surround lighting processor controls further is connected to the state of ambient light sensor circuit.

As shown in figure 10, the present invention may further include the surround lighting processor controls 200 that is used to handle from the signal of ambient light sensor circuit 100.Ambient light sensor circuit 100 can be any one that select from Fig. 1 a to Fig. 1 c, Fig. 3 to Fig. 7 and ambient light sensor circuit shown in Figure 9.In addition, surround lighting processor controls 200 comprises analog-digital converter 210, first memory 220, controller 230 and second memory 240.

Analog-digital converter 210 is by 5 electric coupling of the 5th switch S.Certainly, output load 120 and load capacitance element CL are included in the analog-digital converter 210.Basically, output load can be the internal load of analog-digital converter, and load capacitance element CL can be the capacitive component that forms in lead (wire).Analog-digital converter 210 converts the analog electrical output flow valuve to digital value and with its output.

First memory 220 is electrically coupled to analog-digital converter 210, and stores digital value according to the state of the current surround lighting that senses temporarily.

Controller 230 is electrically coupled to storer 220, with the brightness of calculating the current surround lighting that senses and with its output.

Second memory 240 is electrically coupled to controller 230, with the digital value of prior storage from the surround lighting acquisition of different brightness.

As mentioned above, by comparing the current brightness of computing environment light from the data of the surround lighting that senses of first memory 220 input and the data of surround lighting of different brightness being stored in second memory 240.

Basically, on the same substrate of the panel of flat panel display equipment, form ambient light sensor circuit 100.On the other hand, can form surround lighting processor controls 200 independently with the form of a chip, but be not limited thereto.Can on the same substrate of display panel, form surround lighting processor controls 200.

Figure 11 illustrates the block diagram of the structure of the flat panel display equipment with ambient light sensor circuit in accordance with a further exemplary embodiment of the present invention.

At this, with block diagram ambient light sensor circuit 100 and surround lighting processor controls 200 are shown, so that describe.Ambient light sensor circuit 100 can be any one that select from Fig. 1 a to Fig. 1 c, Fig. 3 to Fig. 7 and ambient light sensor circuit shown in Figure 9.

With reference to Figure 11, except ambient light sensor circuit 100 and surround lighting processor controls 200, flat panel display equipment can also comprise time schedule controller 300, data driver 400, organic electroluminescence panel 500, scanner driver 600 and light emitting control driver 700.Explain the structure and the operation of ambient light sensor circuit 100 and surround lighting processor controls 200 in the superincumbent explanation in detail, therefore omitted detailed explanation below.In addition, in organic electroluminescence panel 500, circuit unit and organic emission layer form a pixel together.With the arranged in form pixel of matrix, to show static or motion image.In other words, in organic electroluminescence panel 500, form a plurality of data line D1 to Dm of beginning to extend from data driver 400, a plurality of sweep trace S1 to Sn that begin to extend from scanner driver 600 and a plurality of light emitting control line E1 to En that begin to extend from light emitting control driver 700.In addition, in the zone that data line, sweep trace and light emitting control line intersect each other, form intended pixel.

Time schedule controller 300 comprises brightness selector switch 310 and look-up table 320.In time schedule controller 300, brightness selector switch 310 will compare from the value surround lighting processor controls 200 digital value of importing and the look-up table that is stored in prior formation, and will output to data driver 400 corresponding to the data controlling signal of this value.Certainly, will match from the optimal brightness data controlling signal of the digital value of surround lighting processor controls 200 inputs among R, G and the B each and be stored in advance the look-up table 320.

Then, data driver 400 outputs to organic electroluminescent device according to surround lighting with suitable data-signal.For example, when the surround lighting that senses is bright relatively, data driver output data voltage | V| is with a large amount of relatively light of output, thus the screen by organic electroluminescence panel 500 exhibit high brilliance.On the other hand, when the surround lighting that senses is dark relatively, data driver output data voltage | V| to be exporting the light of relative a small amount of, thereby shows the screen of low-light levels by organic electroluminescence panel 500.

As mentioned above, according to the present invention, provide the display device that to control screen intensity according to surround lighting automatically.Scanner driver 600 outputs to organic electroluminescence panel 500 with sweep signal, with the pixel of selecting more to be switched on or switched off.Light emitting control driver 700 will output to organic electroluminescence panel 500 corresponding to the fluorescent lifetime signal of turn-on time of each pixel.Scanner driver 600 and light emitting control driver 700 are well-known for the art technology people, so detailed.

On the other hand, can on a public substrate, form ambient light sensor circuit 100, surround lighting processor controls 200, time schedule controller 300, data driver 400, organic electroluminescence panel 500, scanner driver 600 and light emitting control driver 700 by semiconductor technology and thin-film technique.Certainly, form on the substrate that can be different with the substrate that forms organic electroluminescence panel 500 in ambient light sensor circuit 100, surround lighting processor controls 200, time schedule controller 300, data driver 400, scanner driver 600 and the light emitting control driver 700 at least any one, but be not limited thereto.

Figure 12 a illustrates the circuit diagram of an example of image element circuit of the organic electroluminescence panel of flat panel display equipment, and Figure 12 b illustrates the sequential chart of image element circuit.Ambient light sensor circuit 100 can be any one that select from Fig. 1 a to 1c, Fig. 3 to 7 and ambient light sensor circuit shown in Figure 9.

With reference to figure 12a, image element circuit comprises provides the sweep trace of sweep signal Sn, data line Dm, the first power lead VDD that first voltage is provided, the second source line VSS that second voltage is provided, the automatic zero set (AZS) line An that the automatic zero set (AZS) signal is provided, the light emitting control line En that led control signal is provided, first to fourth transistor T 1 to T4, the first capacitive element C1, the second capacitive element C2 and the Organic Light Emitting Diode (OLED, organiclight emittingdiode) of data voltage are provided.At this, the voltage of the first power lead VDD is relatively higher than the voltage of second source line VSS.

With reference to figure 12b, in this image element circuit, when with low level control signal when automatic zero set (AZS) line An is provided to the control electrode of the

3rd transistor T

3,3 conductings of the 3rd transistor T.Next, when with the control signal of high level when light emitting control line En is provided to the control electrode of the 4th transistor T 4, the 4th transistor T 4 turn-offs.Then, T1 forms the diode syndeton, and the threshold voltage of T1 is stored among the first capacitive element C1.On the other hand, when the automatic zero set (AZS) signal becomes high level and when data line Dm applies data voltage corresponding to the predeterminated level of surround lighting, will have the control electrode (data write operation) that is provided to the first transistor T1 with the data voltage of the threshold voltage of the ratio compensation of the first capacitive element C1 and the second capacitive element C2.Next, when led control signal becomes low level, 4 conductings of the 4th transistor T and predetermined current flows Organic Light Emitting Diode (OLED), thus send light.

According to aforesaid image element circuit, the electric current that flows through Organic Light Emitting Diode only flows corresponding to the data voltage that applies from data line, and irrelevant with the threshold voltage of the first transistor.That is, according to this image element circuit, threshold voltage poor of compensation the first transistor, thus the organic electro-luminescence display device of high grade grey level is provided.

According to the present invention, come the brightness of automatic control flow curtain according to ambient brightness.In other words, control is from the data voltage of the data line Dm of image element circuit, and correspondingly control the coupled voltages of the first capacitive element C1 and the second capacitive element C2, thereby change the electric current that flows to Organic Light Emitting Diode (OLED) by the first transistor T1.Therefore, change electric current by Organic Light Emitting Diode (OLED), thus the brightness of control organic electroluminescence panel.

Figure 13 a illustrates the block diagram of the structure of the flat panel display equipment with ambient light sensor circuit in accordance with a further exemplary embodiment of the present invention, and Figure 13 b illustrates the sequential chart of this equipment.Ambient light sensor circuit 100 can be any one that select from Fig. 1 a to 1c, Fig. 3 to 7 and ambient light sensor circuit shown in Figure 9.

With reference to figure 13a, difference with flat panel display equipment of the flat panel display equipment of ambient light sensor circuit and Figure 11 is not to be input to data driver 400 from the brightness control signal of time schedule controller 300 outputs, but is input to light emitting control driver 700.

Then, light emitting control driver 700 will output to organic electroluminescence panel 500 corresponding to the led control signal of surround lighting.For example, when the surround lighting that senses was bright relatively, 700 outputs of light emitting control driver are led control signal relatively for a long time, thereby passed through the screen of organic electroluminescence panel 500 exhibit high brilliance.On the other hand, when the surround lighting that senses is dark relatively, the led control signal of 700 relative short time of output of light emitting control driver, thus pass through the screen that organic electroluminescence panel 500 shows low-light levels.

As mentioned above, according to the present invention, provide and to come the display device of automatic control flow curtain brightness according to surround lighting.

More specifically, shown in Figure 13 b, the length of the time T by control led control signal En is controlled the fluorescent lifetime of Organic Light Emitting Diode (OLED).For example, when ambient brightness is dark, provide short relatively light emitting control time T,, thereby show dark screen with the fluorescent lifetime of relative shortening Organic Light Emitting Diode (OLED).On the other hand, when ambient brightness is bright, provide long relatively light emitting control time T,, thereby show bright screen with the fluorescent lifetime of relative prolongation Organic Light Emitting Diode (OLED).

Figure 14 a illustrates the block diagram of the structure of the flat panel display equipment with ambient light sensor circuit in accordance with a further exemplary embodiment of the present invention, and Figure 14 b illustrates the sequential chart of this equipment.Ambient light sensor circuit 100 can be any one that select from Fig. 1 a to 1c, Fig. 3 to 7 and ambient light sensor circuit shown in Figure 9.

With reference to figure 14a, this difference with flat panel display equipment of the flat panel display equipment of ambient light sensor circuit and Figure 13 a is not to be input to data driver 700 from the brightness control signal of time schedule controller 300 outputs, but is input to power-supply controller of electric 800.

Then, power-supply controller of electric 800 will output to organic electroluminescence panel 500 corresponding to the supply voltage of surround lighting.For example, when the surround lighting that senses was bright relatively, power-supply controller of electric 800 provided high relatively supply voltage, reducing the brightness of Organic Light Emitting Diode (OLED) relatively, thus the screen by organic electroluminescence panel 500 exhibit high brilliance.On the other hand, when the surround lighting that senses was dark relatively, power-supply controller of electric 800 provided low relatively supply voltage, thereby showed the screen of low-light level by organic electroluminescence panel 500.Unaccounted Reference numeral PL is illustrated in the power lead that forms in the organic electroluminescence panel in the accompanying drawing.

As mentioned above, according to the present invention, provide the display device that to control screen intensity according to surround lighting automatically.

In other words, shown in Figure 14 b, control the brightness of Organic Light Emitting Diode (OLED) by the voltage (being expressed as " V " in the drawings) of controlling the first power vd D.For example, when ambient brightness is dark, provide low relatively supply voltage, reducing the brightness of Organic Light Emitting Diode (OLED) relatively, thereby show dark screen.On the other hand, when ambient brightness is bright, provide high relatively supply voltage,, thereby show bright screen with the brightness of relative increase Organic Light Emitting Diode (OLED).

Figure 15 illustrates the block diagram of the structure of the flat panel display equipment with ambient light sensor circuit in accordance with a further exemplary embodiment of the present invention.Ambient light sensor circuit 100 can be any one that select from Fig. 1 a to 1c, Fig. 3 to 7 and ambient light sensor circuit shown in Figure 9.

With reference to Figure 15, flat panel display equipment can comprise ambient light sensor circuit 100, surround lighting processor controls 200, time schedule controller 300, inverter 910, backlight 920, gate drivers 930, data driver 940 and display panels 950.Describe the structure and the operation of ambient light sensor circuit 100, surround lighting processor controls 200 and time schedule controller 300 in the superincumbent description in detail, thereby the detailed explanation of following omission.

Time schedule controller 300 outputs to inverter 910 with brightness control signal.

Then, inverter 910 will be provided to backlight 920 corresponding to the voltage of the raising of surround lighting.For example, when the surround lighting that senses was bright relatively, 910 pairs backlight 920 of inverters provided the voltage of high relatively raising, thus the screen by display panels 950 exhibit high brilliance.On the other hand, when the surround lighting that senses was dark relatively, 910 pairs backlight 920 of inverters provided the voltage of low relatively raising, thereby showed the screen of low-light levels by display panels 950.

In display panels 950, circuit unit and color filter form a pixel P together.With the arranged in form pixel of matrix, to show static or motion image.Certainly, come operation circuit unit and color filter as a kind of camera shutter, and will be such as cold-cathode fluorescence lamp (CCFL, coldcathode fluorescent lamp) backlight 920 back sides that are arranged in display panels 950, thus the image of predetermined luminance shown by light from 920 outputs backlight.In addition, can in display panels 950, form a plurality of sweep trace S1 to Sn that begin to extend from gate drivers 930 and a plurality of data line D1 to Dm that begin to extend from data driver 940.

930 pairs of display panels 950 of gate drivers provide sweep signal.940 pairs of display panels 950 of data driver provide data voltage.Gate drivers 930 and data driver 940 are well-known to those skilled in the art, therefore, omit detailed explanation.

On the other hand, can on a public substrate, form ambient light sensor circuit 100, surround lighting processor controls 200, time schedule controller 300, inverter 910, gate drivers 930, data driver 940 and display panels 950 by semiconductor technology and thin-film technique.Certainly, can on substrate different or chip, form with the substrate that forms display panels 950 in ambient light sensor circuit 100, surround lighting processor controls 200, time schedule controller 300, inverter 910, gate drivers 930 and the data driver 940 at least any one, but be not limited thereto.

Figure 16 shows the block diagram of an example that is shown specifically inverter shown in Figure 15.

With reference to Figure 16, inverter 910 can comprise: PWM controller 911, and its output is corresponding to the pwm control signal of the control signal of importing from time schedule controller 300 relevant with brightness; Converter 912, its output signal that receives PWM controller 911 be as input signal, and supply voltage VDD is brought up to predeterminated level and the voltage that improves is offered backlight 920; And current sensor 913, its senses flow is crossed backlight 920 electric current and is given PWM controller 911 with the current feedback that senses.Certainly, the structure of inverter 910 only is an example, but is not limited thereto.

As mentioned above, relevant with brightness control signal can be input to PWM controller 911 from time schedule controller 300.

Then, PWM controller 911 will output to converter with the pwm control signal of control signal coupling.In other words, when current environment light is dark, the voltage that PWM controller 911 output pwm control signals improve with relative reduction, when the current environment light, the voltage that PWM controller 911 output pwm control signals improve with relative increase.

Then, after converter 912 received supply voltage VDD, converter 912 was brought up to predetermined voltage in response to pwm control signal with it.Therefore, backlight 920 connect with predetermined luminance.At this, when the voltage that improves was low, backlight 920 reduced brightness, and when the voltage that improves was high, backlight 920 increased brightness.

On the other hand, the current sensor 913 that is formed by a plurality of resistors, diode and capacitive element will flow through backlight 920 electric current and be reduced to predeterminated level, and it is fed back to PWM controller 911.Thereby PWM controller 911 can control backlight 920 effectively according to desired brightness.

As mentioned above, according to the present invention, when surround lighting is dark, relatively secretly connect backlight 920, thereby show dark relatively screen by display panels 950.On the other hand, when environment bright, connect relatively brightly backlight 920, thereby show bright relatively screen by display panels 950.Thereby flat panel display equipment can automatically be controlled the brightness of screen corresponding to surround lighting.

As mentioned above, produce following effect according to ambient light sensor circuit of the present invention and flat panel display equipment with this circuit.

The first, by sensitive context brightness and control output current and control the screen intensity of flat panel display equipment automatically, improved the visuality of flat panel display equipment in bright place and dark place according to ambient brightness.

The second, keep optimal power by controlling power consumption automatically according to ambient brightness, prolonged the life-span of portable flat panel display equipment.

The 3rd, by on the same substrate that forms organic electroluminescence panel (or liquid crystal panel), forming ambient light sensor circuit, surround lighting processor, time schedule controller, data driver, scanner driver and photocontrol driver, can prevent from unnecessarily to increase the size and the thickness of flat panel display equipment.

The 4th, by the light leakage current that in the sampling time of surround lighting section, interrupts applying, prevent that light leakage current from causing that output current changes, and can sample to surround lighting exactly from light receiving element.

The 5th, can prevent that the temperature leakage current from causing that according to the increase of environment temperature the output current of ambient light sensor circuit changes.

It will be appreciated by those skilled in the art that can carry out the various of form and details substitutes, revises and change, and the spirit and scope of the present invention that do not break away from claims and limited.Therefore, should be appreciated that the foregoing description only is used to describe, and it can not be interpreted as limitation of the present invention.

Claims

1. ambient light sensor circuit comprises:

Transistor, it comprises first electrode that is electrically coupled to first power supply;

First capacitive element, it comprises first electrode that is electrically coupled to described transistorized control electrode and second electrode that is electrically coupled to first reference power supply;

Second capacitive element, second electrode that it comprises first electrode of second electrode that is electrically coupled to described first capacitive element and is electrically coupled to second reference power supply;

First light receiving element, its electric coupling between described first reference power supply and the 3rd reference power supply, and by in response to surround lighting conduction current control the charging of the coupled voltages and described second capacitive element of described first capacitive element;

First switch, it is electrically coupled to described transistorized second electrode, and makes that described transistor can be according to the described coupled voltages output of described first capacitive element electric current from described first power supply;

Second switch, its electric coupling and interrupt the leakage current of described first light receiving element between described first light receiving element and described first capacitive element, thereby the described coupled voltages that prevents described first capacitive element is changed;

The 3rd switch, the 3rd switch electric coupling make first reference voltage is applied to described first and second capacitive elements from described first reference power supply via described second switch between described first reference power supply and described second switch;

The 4th switch, the 4th switch electric coupling and make described transistor can form the diode syndeton between described transistorized control electrode and described first switch;

The 5th switch, the 5th switch electric coupling make via described first switch reference current to be applied to described transistor, thereby predetermined voltage are applied to described transistorized control electrode between described first switch and reference current source;

The 6th switch, the 6th switch are electrically coupled to described first switch, and make described transistor scheduled current to be sent to output terminal from described first power supply via described first switch in response to the coupled voltages of described first and second capacitive elements;

The 3rd capacitive element, the 3rd capacitive element are electrically coupled to described second capacitive element, and increase the reverse bias ability of described first light receiving element; And

Minion is closed, and this minion is closed electric coupling between the described second and the 3rd capacitive element, makes them be electrically coupled to one another.

2. ambient light sensor circuit according to claim 1, wherein, described first light receiving element is any one that select from p-intrinsic-n (p-i-n) diode, p-intrinsic-metal (p-i-m) diode, p-n diode and photoelectrical coupler, the anode of described first light receiving element is electrically coupled to described first reference power supply, and cathodic electricity is coupled to described the 3rd reference power supply.

3. ambient light sensor circuit according to claim 2, wherein, the 3rd reference voltage that applies from described the 3rd reference power supply is higher than first reference voltage that applies from described first reference power supply.

4. ambient light sensor circuit according to claim 1, wherein, described first light receiving element is any one that select from p-intrinsic-n (p-i-n) diode, p-intrinsic-metal (p-i-m) diode, p-n diode and photoelectrical coupler, the cathodic electricity of described first light receiving element is coupled to described first reference power supply, and anode is electrically coupled to described the 3rd reference power supply.

5. ambient light sensor circuit according to claim 4, wherein, the 3rd reference voltage that applies from described the 3rd reference power supply is lower than first reference voltage that applies from described first reference power supply.

6. ambient light sensor circuit according to claim 1, also comprise second light receiving element, this second light receiving element electric coupling is between described first light receiving element and the 4th reference power supply, and comprise light shield layer, because the surround lighting crested, therefore described second light receiving element only sensing depend on the leakage current of the increase of temperature.

7. ambient light sensor circuit according to claim 1, also comprise second light receiving element, this second light receiving element electric coupling is between described first light receiving element and the 4th reference power supply, and comprise light shield layer, because the surround lighting crested, therefore described second light receiving element only sensing depend on the leakage current of the increase of temperature.

8. ambient light sensor circuit according to claim 1 also comprises:

Temperature sensor, its sensing temperature;

Look-up table, it is electrically coupled to described temperature sensor, and storage is corresponding to the surround lighting sensing time of the temperature that senses; And

Controller, it is electrically coupled to described look-up table, and first control signal is offered described first switch in response to the described surround lighting sensing time from the output of described look-up table.

9. ambient light sensor circuit according to claim 1 also comprises:

Temperature sensor, its sensing temperature;

Controller, it is electrically coupled to described look-up table, and in response to the described surround lighting sensing time from described look-up table output, by described first switch of the first control signal on/off, by the described second switch of the second control signal on/off, by described the 3rd switch of the 3rd control signal on/off and described the 4th switch, by described the 5th switch of the 4th control signal on/off, by described the 6th switch of the 5th control signal on/off, and by the described minion of the 6th control signal on/off pass.

10. ambient light sensor circuit according to claim 1 also comprises:

First switching transistor, its first and second electrodes electric coupling is between described first and second capacitive elements, and its control electrode is electrically coupled to the second negative control signal; And

Second switch transistor, its first and second electrode are electrically coupled to described transistorized described control electrode, and its control electrode is electrically coupled to the 3rd negative control signal.

11. ambient light sensor circuit according to claim 1 also comprises:

12. ambient light sensor circuit according to claim 1, wherein, the described the 4th and each switch in the minion Central Shanxi Plain form by two transistors that are connected in series.

13. a flat panel display equipment comprises:

The ambient light sensor circuit, it comprises: transistor, it comprises first electrode that is electrically coupled to first power supply; First capacitive element, its electric coupling is between the described transistorized control electrode and first reference power supply; Second capacitive element, second electrode that it comprises first electrode of second electrode that is electrically coupled to described first capacitive element and is electrically coupled to second reference power supply; First light receiving element, its electric coupling between described first reference power supply and the 3rd reference power supply, and by in response to surround lighting conduction current control the charging of the coupled voltages and described second capacitive element of described first capacitive element; First switch, it is electrically coupled to described transistorized second electrode, and makes that described transistor can be according to the electric current of the coupled voltages of described first capacitive element output from described first power supply; And second switch, its electric coupling and is interrupted the leakage current of described first light receiving element between described first light receiving element and described first capacitive element, thus the coupled voltages that prevents described first capacitive element is changed;

The surround lighting processor controls, it receives analog output signal from described ambient light sensor circuit as input signal, and calculates current environment light and it is exported as digital value;

Time schedule controller, it receives output signal from described surround lighting processor controls as input signal, and output is corresponding to the control signal of described current environment light; And

Organic electroluminescence panel, it receives the control signal corresponding to described current environment light that applies from described time schedule controller, and to send light corresponding to the brightness of described current environment light;

Wherein said ambient light sensor circuit also comprises the 3rd switch, the 3rd switch electric coupling makes first reference voltage is applied to described first and second capacitive elements from described first reference power supply via described second switch between described first reference power supply and described second switch;

Described ambient light sensor circuit also comprises the 4th switch, and the 4th switch electric coupling and makes described transistor can form the diode syndeton between described transistorized control electrode and described first switch;

Described ambient light sensor circuit also comprises the 5th switch, the 5th switch electric coupling is between described first switch and reference current source, make reference current to be applied to described transistor, thereby predetermined voltage is applied to described transistorized control electrode via described first switch;

Described ambient light sensor circuit also comprises the 6th switch, the 6th switch is electrically coupled to described first switch, and makes described transistor scheduled current to be sent to output terminal from described first power supply via described first switch in response to the coupled voltages of described first and second capacitive elements;

Described ambient light sensor circuit also comprises the 3rd capacitive element, and the 3rd capacitive element is electrically coupled to described second capacitive element, and increases the reverse bias ability of described first light receiving element; And

Described ambient light sensor circuit also comprises the minion pass, and this minion is closed electric coupling between the described second and the 3rd capacitive element, makes them be electrically coupled to one another.

14. flat panel display equipment according to claim 13, wherein, described time schedule controller comprises:

Look-up table, its storage is corresponding to the data of current environment brightness; And

The brightness selector switch, it will compare with the data that are stored in the described look-up table from the data of described surround lighting processor controls input, and selects to output to data driver corresponding to the data controlling signal of described current environment brightness and with it.

15. flat panel display equipment according to claim 13, also comprise data driver, this data driver receives output signal from described time schedule controller as input signal, and output is applied to described organic electroluminescence panel corresponding to the data-signal of current environment brightness and with it.

16. flat panel display equipment according to claim 13, also comprise the light emitting control driver, this light emitting control driver receives output signal from described time schedule controller as input signal, and output led control signal and it is applied to described organic electroluminescence panel.

17. flat panel display equipment according to claim 13, also comprise power-supply controller of electric, this power-supply controller of electric receives output signal from described time schedule controller as input signal, and output is applied to described organic electroluminescence panel corresponding to the supply voltage of described current environment light and with it.

18. a flat panel display equipment comprises:

Time schedule controller, it receives output signal from described surround lighting processor controls as input signal, and output is corresponding to the control signal of described current environment light;

Inverter, it receives output signal from described time schedule controller as input signal, and supply voltage is brought up to corresponding to the level of described current environment light and with its output;

Backlight, it comes on/off by the voltage that applies from described inverter; And

Display panels, it is by the described display screen that comes backlight;