Patent Description:
Electronic devices such as mobile phones include ambient light detectors that automatically adjust brightness of a display screen by detecting brightness of ambient light. The traditional ambient light detection is implemented by a photoelectric sensor at a front end of the mobile phone, which requires a separate sensor and compresses the space of other devices; moreover, when the display screen is a full screen, a special hollowing-out is required to place the photoelectric sensor. This may increase process complexity and reduce user experience.

Display brightness control apparatuses as well as aspects thereof are for example known from documents <CIT>, <CIT>, <CIT> and <CIT>.

In view of the forgoing, the present disclosure provides a display brightness control apparatus, applied to a display panel, the display panel including a thin film transistor unit and a light emitting unit, the apparatus comprising:.

According to the invention, the detection module includes one or more detection units, and to control the luminous brightness of the light emitting unit according to the detection current includes:
obtaining a first control signal according to the detection current outputted by the one or more detection units to control the luminous brightness of the light emitting unit.

In an implementation not part to the invention, the detection unit includes a first diode, a first capacitor, a second capacitor, a first switch, and a second switch, wherein.

In an implementation not part of the invention, the control module includes a first operational amplifier, a third capacitor, a third switch, and a first control unit, wherein.

In an implementation not part of the invention, to control the on states of the first switch, the second switch, and the third switch through the control end of the first switch, the control end of the second switch, and the control end of the third switch so as to control the detection unit to obtain the detection current includes:.

According to the invention, the detection unit includes a second diode, a third diode, a fourth switch, a fifth switch, a first transistor, and a second transistor, wherein.

In a possible implementation, the control module includes a second operational amplifier, a fourth capacitor, a sixth switch, and a second control unit, wherein.

In a possible implementation, to control the on states of the fourth switch, the fifth switch, and the sixth switch through the control end of the fourth switch, the control end of the fifth switch, and the control end of the sixth switch so as to control the detection unit to obtain the detection current includes:.

In a possible implementation, the control module is arranged in any one of a touch and display driver integration (TDDI), a fingerprint touch and display driver integration (FTDDI), or a fingerprint and display driver integration (FDDI).

According to another aspect of the present disclosure, there is provided an electronic device, comprising:.

In a possible implementation, the display panel includes at least one of a liquid crystal display panel, a light-emitting diode display panel, an organic light-emitting diode display panel, or a microlight-emitting diode display panel.

In a possible implementation, the micro light-emitting diode display panel includes a Mini LED or a Micro LED.

In various aspects of the embodiments of the present disclosure, the detection module is implemented by the thin film transistors and is arranged in the thin-film transistor unit of the display panel, and the photosensitive characteristic of the thin film transistors is used to detect the brightness of the ambient light. Thus the occupied space is small, and a hollowing-out is not required in the case of a full screen, such that the process complexity is low. Compared with the related technology, the present disclosure has the characteristic of low cost, and can improve user experience.

Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the accompanying drawings.

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features and aspects of the present disclosure together with the specification, and serve to explain the principles of the present disclosure.

Hereinafter, various exemplary embodiments, features and aspects of the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to elements with the same or similar functions. Although various aspects of the embodiments are shown in the figures, the figures are not necessarily drawn to scale unless otherwise specified.

The special word "exemplary" here means "serving as an example, embodiment or illustration". Any embodiment described herein as "exemplary" need not be interpreted as superior to or better than other embodiments.

In addition, in order to better describe the present disclosure, numerous specific details are provided in the following detailed embodiments. It is understood by those skilled in the art that the present disclosure can also be practiced without certain specific details. In some embodiments, methods, means, elements, and circuits well known to those skilled in the art are not elaborated in order to highlight the main idea of the present disclosure.

Please refer to <FIG> which shows a block diagram of a display brightness control apparatus according to an embodiment of the present disclosure.

The display brightness control apparatus can be applied to a display panel, and the display panel includes a thin film transistor unit and a light emitting unit. As shown in <FIG>, the apparatus comprises:.

In the display brightness control apparatus provided by an embodiment of the present disclosure, the detection module is implemented by the thin film transistors and is arranged in the thin-film transistor unit of the display panel, and the photosensitive characteristic of the thin film transistors is used to detect the brightness of the ambient light. Thus the occupied space is small, and a hollowing-out is not required in the case of a full screen, such that the process complexity is low. Compared with the related technology, the present disclosure has the characteristic of low cost, and can improve user experience.

A specific type of the display panel is not limited by the present disclosure. The display panel may be a self-luminous type display panel, or may be a backlight type display panel, which may be selected by those skilled in the art as needed.

In an example, the display panel may be the self-luminous type display panel, e.g., an organic light emitting diode (OLED) display panel. In this case, the light emitting unit may refer to the display panel itself, and the control module <NUM> may control the luminous brightness of the display panel according to the detection current; the thin film transistor unit may include a plurality of thin film transistors arranged on a substrate.

In an example, the display panel may be the backlight type display panel, e.g., a liquid crystal display panel. In this case, the light emitting unit may refer to a backlight layer in the display panel, and the control module <NUM> may control the luminous brightness of the backlight layer according to the detection current; the thin film transistor unit may include a plurality of thin film transistors arranged on a substrate.

The display panel may be arranged in an electronic device. The electronic device may also be referred to as a mobile equipment, which may be various forms of access mobile equipment, subscriber unit, user equipment, subscriber station, rover station, Mobile Station (MS), remote station, remote mobile equipment, mobile equipment, user mobile equipment, terminal equipment, wireless communication equipment, user agent, or user apparatus. The user equipment may also be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld equipment with wireless communication function, a computing equipment or other processing equipment connected to wireless modem, a vehicle-mounted equipment, a wearable equipment, a user equipment in the future <NUM> network, or a mobile equipment in the future evolved Public Land Mobile Network (PLMN), etc.; embodiments of the present disclosure are not limited thereto.

In a possible implementation, as shown in <FIG>, the detection module includes one or more detection units <NUM>, and the controlling luminous brightness of the light emitting unit according to the detection current may include:
obtaining a first control signal according to the detection current outputted by the one or more detection units <NUM>, so as to control the luminous brightness of the light emitting unit.

With the above apparatus, in the embodiment of the present disclosure, the luminous brightness of the display panel may be controlled by the detection current outputted by the one or more detection units.

In an example, a plurality of detection units <NUM> may be used, the plurality of detection units <NUM> are distributed on a plurality of positions of the thin film transistor unit to obtain a plurality of detection current; and the control module <NUM> may obtain a control signal according to each of the detection currents, and integrates a plurality of control signals into the first control signal to control the luminous brightness of the display panel. In this way, the display brightness control apparatus provided by an embodiment of the present disclosure may obtain a more accurate first control signal, so as to better adapt to the change of the ambient light.

Of course, in other implementations, only one detection unit may also be used to detect the brightness of the ambient light, which can better reduce the cost and respond to the change in the brightness of the ambient light more quickly.

The detection unit <NUM> in the embodiment of the present disclosure may include numerous possible implementations. When the detection module <NUM> includes a plurality of detection units <NUM>, each of the detection units <NUM> may be the same, or may be different. Possible implementations of the detection unit <NUM> are described exemplarily below.

Please refer to <FIG> which shows a schematic diagram of a display brightness control apparatus according to an embodiment, not part of the invention.

As shown in <FIG>, the detection unit <NUM> may include a first diode D1, a first capacitor C1, a second capacitor C2, a first switch K1, and a second switch K2, wherein,.

According to an embodiment, which is not part of the invention, a plurality of thin film transistors are connected in parallel to obtain a first diode D1, and the photosensitive characteristic of the thin film transistors may be used to detect the brightness of the ambient light.

As shown in <FIG>, the control module <NUM> may include a first operational amplifier A1, a third capacitor C3, a third switch K3, and a first control unit <NUM>, wherein,.

In a possible implementation, not part of the invention, the first control unit <NUM> may include a digital-analog converter, a micro processor MCU, a digital signal processor DSP, etc., so as to convert a voltage signal VCA outputted by the first operational amplifier A1 into the first control signal.

In a possible implementation, not part of the invention, the controlling on states of the first switch K1, the second switch K2, and the third switch K3 through the control end of the first switch K1, the control end of the second switch K2, and the control end of the third switch K3 so as to control the detection unit <NUM> to obtain the detection current may include:.

During the first time period when the detection starts, when the first switch K1 is turned on and the second switch K2 is turned off, the second capacitor C2 may be charged, and when the third switch K3 is turned on, a setting may be performed on the first operational amplifier A1.

When the first time period is reached, the second switch K2 is turned on, the first switch K1 and the third switch K3 are turned off, the second capacitor C2 begins to be discharged, and the output end of the first operational amplifier A1 outputs the voltage signal VCA, wherein VCA=i1*t1/C3, i1 being magnitude of the current (i.e. detection current) inputted to the first input end of the first operational amplifier when the capacitor C2 is discharged, and t1 being detection time.

According to the embodiment of <FIG>, by controlling on states of the first switch K1, the second switch K2, and the third switch K3 with the first control unit <NUM>, sampling of the detection current may be realized and the corresponding voltage signal may be obtained; and by arranging the first capacitor C1 and the second capacitor C2, the size of the third capacitor C3 may be reduced, thereby saving the space and the cost.

In an example, if a change of the voltage VCA outputted by the first operational amplifier A1 is to be controlled within 2V, the third capacitor is required to be at least <NUM> pF; and according to the embodiment of the present disclosure, by arranging the first capacitor C1 and the second capacitor C2, the size of the third capacitor C3 may be reduced to <NUM>/<NUM> of its original size.

In an example, the capacitance value of the first capacitor C1 may be <NUM> times of the capacitance value of the second capacitor C2.

It should be noted that the specific duration of the first time period is not limited by the embodiment of the present disclosure, and may be set by those skilled in the art as needed.

Other possible implementations of the detection unit <NUM> and the control module <NUM> are described below.

Please refer to <FIG> which shows a schematic diagram of a display brightness control apparatus according to an embodiment of the invention.

According to the invention and as shown in <FIG>, the detection unit <NUM> includes a second diode D2, a third diode D3, a fourth switch K4, a fifth switch K5, a first transistor Q1, and a second transistor Q2, wherein,.

According to the embodiment of the present disclosure, the second diode D2 and the third diode D3 are implemented by a plurality of thin film transistors connected in parallel, the third diode D3 is arranged not to be irradiated by the ambient light, the photosensitive characteristic of the thin film transistors may be used to detect the ambient light, and with the third diode D3 as a reference, the base current present in the thin film transistors themselves may be eliminated, thereby improving the signal-to-noise ratio.

In a possible implementation, as shown in <FIG>, the control module <NUM> may include a second operational amplifier A2, a fourth capacitor C4, a sixth switch K6, and a second control unit <NUM>, wherein,.

In a possible implementation, the controlling on states of the fourth switch K4, the fifth switch K5, and the sixth switch K6 through the control end of the fourth switch K4, the control end of the fifth switch K5, and the control end of the sixth switch K6 so as to control the detection unit <NUM> to obtain the detection current may include:.

Wherein during the second time period when the detection starts, according to the embodiment of the present disclosure, a setting is performed on the second operational amplifier A2 by turning on the sixth switch and turning off the fourth switch and the fifth switch. When the second time period is reached, according to the embodiment of the present disclosure, by turning on the fourth switch and the fifth switch and turning off the sixth switch, the detection current is obtained by the detection unit <NUM>. Wherein, a light shielding process is performed on the third diode D3, the base current may be outputted, the second diode D2 senses the brightness of the ambient light to output a first current, and a current mirror composed of the first transistor Q1 and the second transistor Q2 obtain a difference between the first current and the base current so as to obtain the detection current. Since the detection current is obtained by removing the base current, the error interference is eliminated and the signal-to-noise ratio is improved.

Of course, in the embodiment of the present disclosure, a difference circuit is described exemplarily by taking the current mirror composed of the first transistor Q1 and the second transistor Q2 as an example, and in other implementations, the difference circuit may also include other elements.

In an example, when the second time period is reached, the fourth switch and the fifth switch are turned on and the sixth switch is turned off, and the output end of the second operational amplifier A2 outputs the voltage signal VCA= i2*t2/C4, where i2 indicates the detection current (a difference current between the first current and the base current) outputted by the detection unit <NUM>, and t2 indicates the single detection time, e.g., <NUM>. If the outputted voltage signal VCA is to be controlled within 2V, the capacitance value of the fourth capacitor C4 may be about <NUM> pF.

In a possible implementation, the second control unit <NUM> may include a digital-analog converter, a micro processor MCU, a digital signal processor DSP, etc. so as to convert the voltage signal VCA outputted by the first operational amplifier A1 into the first control signal.

In a possible implementation, after obtaining the voltage signal VCA, the first control unit <NUM> and the second control unit <NUM> may process the voltage signal VCA in the same way. The process on the voltage signal VCA is exemplarily described below, and it should be noted that the following description is applicable to the first control unit <NUM> and the second control unit <NUM>.

In a possible implementation, after obtaining the voltage signal VCA, the embodiment of the present disclosure may perform analog-digital conversion on the voltage signal VCA to obtain a digital signal corresponding to the voltage signal, the digital signal may be stored in a storage unit (e.g., SRAM); and by invoking a preset light intensity lookup table stored in the storage unit, an ambient light intensity corresponding to the digital signal may be obtained, and the obtained ambient light intensity may be used to obtain the first control signal.

The preset light intensity lookup table may include a correspondence between the voltage (digital signal) and the ambient light intensity; and therefore, after the voltage is obtained, the corresponding ambient light intensity may be found by the voltage.

It should be noted that the specific implementation of obtaining the first control signal by the found ambient light intensity is not limited by the present disclosure, and may be determined by those skilled in the art according to the related technology.

In a possible implementation, when the detection module <NUM> includes a plurality of detection units, a plurality of control signals may be obtained; and in this case, the embodiment of the present disclosure performs processes such as weighted average on the plurality of control signals to obtain the first control signal, so that the luminous brightness of the display panel responds to the change of the ambient light more accurately.

Of course, the above description is exemplary, and should not be regarded as a limitation to the present disclosure; and in other implementations, other processes may also be performed on the plurality of first control signals, which is not limited by the present disclosure.

It should be noted that since there are various kinds of display panels such as a self-luminous type and a backlight type, the specific way of controlling the luminous intensity of the display panel by the first control signal is not limited by the present disclosure. For example, as for the self-luminous type display panel (e.g., OLED), the first control signal may be used to directly control the luminous brightness of the display panel; and as for the backlight type display panel (e.g., LCD), the first control signal may be used to control the luminous brightness of the backlight layer so as to control the luminous brightness of the display panel.

Please refer to <FIG> which shows a schematic diagram of a display brightness control apparatus according to an embodiment of the present disclosure.

As shown in <FIG>, the detection module <NUM> may be arranged in the display panel, and the control module <NUM> may be arranged in a control chip (or referred to as a multiplex control chip); when obtaining the detection current, the detection module <NUM> transmits the detection current to the control module <NUM> of the control chip through a new connecting wire, and the control module <NUM> obtains the first control signal according to the detection current so as to control the luminous brightness of the display panel.

In a possible implementation, the control chip may include any one of a touch and display driver integration, a fingerprint touch and display driver integration, or a fingerprint and display driver integration. That is, the control module <NUM> may reuse the control chip of the display panel itself to control the detection module and the luminous brightness of the display panel, so that the cost may be saved.

Although embodiments of the present disclosure have been described above, the above descriptions are exemplary but not exhaustive, and are not limited to each of the disclosed embodiments.

Claim 1:
A display brightness control apparatus,
wherein the display brightness control apparatus is applied to a display panel, the display panel includes a thin film transistor unit and a light emitting unit, and the display brightness control apparatus comprises:
a detection module (<NUM>), including a plurality of thin film transistors in the thin film transistor unit, and configured to output a detection current according to brightness of ambient light; and
a control module (<NUM>), electrically connected to the detection module (<NUM>), and configured to control luminous brightness of the light emitting unit according to the detection current;
wherein the detection module (<NUM>) includes one or more detection units (<NUM>), and to control the luminous brightness of the light emitting unit according to the detection current includes:
obtaining a first control signal according to the detection current outputted by the one or more detection units (<NUM>) to control the luminous brightness of the light emitting unit,
characterized in that the detection unit (<NUM>) includes a second diode (D2), a third diode (D3), a fourth switch (K4), a fifth switch (K5), a first transistor (Q1), and a second transistor (Q2), wherein
a positive end of the second diode (D2) is electrically connected to a first end of the fourth switch (K4), and a second end of the fourth switch (K4) is electrically connected to a drain of the second transistor (Q2) and the control module (<NUM>),
a positive end of the third diode (D3) is electrically connected to a first end of the fifth switch (K5), and a second end of the fifth switch (K5) is electrically connected to a drain of the first transistor (Q1), a gate of the first transistor (Q1), and a gate of the second transistor (Q2),
a control end of the fourth switch (K4) and a control end of the fifth switch (K5) are electrically connected to the control module (<NUM>),
a negative end of the second diode (D2), a negative end of the third diode (D3), a source of the first transistor (Q1), and a source of the second transistor (Q2) are grounded,
wherein the second diode (D2) and the third diode (D3) each includes a plurality of thin film transistors connected in parallel, the second diode (D2) is arranged to sense the brightness of the ambient light and the third diode (D3) is arranged not to be irradiated by the ambient light.