Display device

Abstract

The invention provides a display device. The display device comprises a plurality of driving transistors, a sensing circuit and a control circuit, the control circuit is coupled with a plurality of driving transistors arranged on the substrate and the sensing circuit; the plurality of driving transistors drive the plurality of light-emitting components; the sensing circuit comprises a thermistor; the sensing circuit generates a sensing voltage according to an input voltage. The control circuit generates a bias voltage according to the sensing voltage based on a plurality of reference tables associated with the resistance, the temperature and the critical voltage value of each driving transistor, and drives the plurality of driving transistors according to the bias voltage, so as to prevent the display frame from being abnormal due to the change of the temperature.

Description

Technical Field

[0001] The invention relates to an electronic device, and in particular to a display equipment. Background Art

[0002] Generally speaking, in a display device, a light-emitting diode (LED) is driven by a driving transistor to emit light. However, when the LED emits light, the temperature of the display device rises accordingly, causing the temperature of the driving transistor to rise. As a result, the rising temperature of the driving transistor affects the driving operation of the LED, thereby affecting the grayscale value of the display device, causing abnormal display images. Summary of the invention

[0003] An embodiment of the present invention provides a display device, which can compensate a driving transistor according to the current temperature of the display device to avoid abnormal display images.

[0004] The display device of an embodiment of the present invention includes multiple driving transistors, at least one sensing circuit and a control circuit, the multiple driving transistors are arranged on a substrate; the multiple driving transistors are used to drive multiple light-emitting components; the sensing circuit includes a thermistor; the sensing circuit is arranged on the substrate; the sensing circuit is used to generate a sensing voltage according to an input voltage; the control circuit couples the multiple driving transistors and the sensing circuit; the control circuit is used to generate a bias voltage according to the sensing voltage based on multiple reference tables associated with resistance, temperature and critical voltage values ​​of each driving transistor, and drive the multiple driving transistors according to the bias voltage.

[0005] In one embodiment of the display device, the control circuit is further used to:

[0006] The sensing voltage is calculated according to the input voltage and voltage division information corresponding to the thermistor to obtain a sensing resistance value of the thermistor.

[0007] In one embodiment of the display device, the control circuit is used to:

[0008] According to the sensed resistance value, searching a first reference table in the plurality of reference tables to obtain a sensed temperature;

[0009] Based on a second reference table in the plurality of reference tables, calculating the sensed temperature to obtain an offset voltage difference for each of the threshold voltage values; and

[0010] The bias voltage is generated according to the offset voltage difference.

[0011] In an embodiment of the display device, the first reference table includes a correspondence between a resistance value of the thermistor and a temperature, and the second reference table includes a correspondence between a temperature and each of the threshold voltage values.

[0012] In an embodiment of the display device, the sensing circuit further includes a second resistor.

[0013] The first end of the thermistor receives the input voltage, the second end of the thermistor is coupled with the first end of the second resistor to output the sensing voltage, and the second end of the second resistor receives a reference voltage.

[0014] In an embodiment of the display device, the material of the second resistor includes polysilicon material.

[0015] In an embodiment of the display device, the thermistor is disposed on the substrate in a bonding manner.

[0016] In an embodiment of the display device, the at least one sensing circuit is provided in plurality, and the plurality of thermistors in the plurality of sensing circuits are respectively disposed at different positions on the substrate.

[0017] In one embodiment of the display device, the multiple sensing circuits respectively generate multiple sensing voltages according to the input voltage, so that the control circuit generates multiple bias voltages corresponding to different positions according to the multiple sensing voltages based on the multiple reference tables, and drives the corresponding multiple driving transistors according to the multiple bias voltages.

[0018] Based on the above, the display device of the embodiment of the present invention can obtain the resistance corresponding to the sensing voltage, the temperature and the critical voltage value of the driving transistor through the thermistor set on the substrate based on multiple preset reference tables. In this way, the display device can generate a bias voltage in response to the current temperature of the display device to compensate for the variation of the driving transistor caused by the temperature, so as to avoid abnormal display images.

[0019] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a block diagram of a display device according to an embodiment of the present invention.

[0021] Figure 2 is a circuit diagram of a sensing circuit according to an embodiment of the present invention.

[0022] Figure 3 is a circuit diagram of a display device according to another embodiment of the present invention.

[0023] Figure 4 According to the present invention Figure 3 A circuit diagram of a pixel unit shown in the embodiment.

[0024] Figure 5 is a block diagram of a display device according to another embodiment of the present invention.

[0025] Wherein, the reference numerals are:

[0026] 100, 300, 500: Display device

[0027] 101, 501: Substrate

[0028] 110, 310: control circuit

[0029] 120, 220, 320, 520-1 to 520-5: Sensing circuit

[0030] 121, 221, 321: Thermistor

[0031] 131~13N, 331: driving transistor

[0032] 141~14N、341: Light-emitting components

[0033] 222, 322: second resistor

[0034] 350: Pixel unit

[0035] D1~DM: Reference table

[0036] GND: reference voltage

[0037] N1: voltage divider node

[0038] PN1~PN4: Pin

[0039] R1~R2: Resistors

[0040] Vbs: Bias voltage

[0041] VDD: reference voltage

[0042] Vin: Input voltage

[0043] Vout: sensing voltage

[0044] VSS: Reference voltage DETAILED DESCRIPTION

[0045] Some embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The component symbols cited in the following description will be regarded as the same or similar components when the same component symbols appear in different drawings. These embodiments are only part of the present invention and do not disclose all possible implementation methods of the present invention. More specifically, these embodiments are only examples within the scope of the patent application of the present invention.

[0046] Figure 1 is a block diagram of a display device according to an embodiment of the present invention. Figure 1 The display device 100 includes a control circuit 110, a sensing circuit 120, a plurality of driving transistors 131 to 13N, and a plurality of light-emitting components 141 to 14N, wherein N is a positive integer greater than 1. The sensing circuit 120, the plurality of driving transistors 131 to 13N, and the plurality of light-emitting components 141 to 14N are all disposed on a substrate 101 of the display device 100. The substrate 101 is, for example, a glass substrate. The control circuit 110 is coupled to the sensing circuit 120 and the plurality of driving transistors 131 to 13N.

[0047] In this embodiment, a plurality of driving transistors 131 to 13N and a plurality of light emitting elements 141 to 14N are disposed in an active region (not shown) of the substrate 101. The plurality of driving transistors 131 to 13N are respectively used to drive the plurality of light emitting elements 141 to 14N to make the light emitting elements 141 to 14N emit light.

[0048] In detail, each driving transistor (e.g., driving transistor 131) is controlled by a control signal (e.g., bias voltage Vbs) from control circuit 110, and drives a corresponding light-emitting component (e.g., light-emitting component 141) according to the control signal. The driving transistor 131 and the corresponding light-emitting component 141 can be used as a single pixel unit (e.g., Figure 4 That is, the driving transistors 131 to 13N and the light emitting components 141 to 14N form a plurality of pixel units. The pixel units are arranged in an array on the substrate 101.

[0049] In this embodiment, each of the driving transistors 131 to 13N is implemented by, for example, a p-type Metal-Oxide-Semiconductor Field-Effect Transistor (PMOSFET) or an n-type Metal-Oxide-Semiconductor Field-Effect Transistor (NMOSFET). Each of the light-emitting components 141 to 14N is implemented by, for example, a light-emitting diode (LED).

[0050] In this embodiment, the sensing circuit 120 is disposed in the active region of the substrate 101 . A first terminal of the sensing circuit 120 receives an input voltage Vin. The input voltage Vin is, for example, a high power voltage. A second terminal of the sensing circuit 120 is coupled to the control circuit 110 .

[0051] In addition, the sensing circuit 120 includes a thermistor 121. Based on the operation of the thermistor 121, the sensing circuit 120 is used to generate a sensing voltage Vout according to the input voltage Vin, and output the sensing voltage Vout to the control circuit 110. The sensing voltage Vout indicates the temperature change sensed by the thermistor 121 on the substrate 101.

[0052] In this embodiment, the control circuit 110 is, for example, a signal converter, a field programmable gate array (FPGA), a central processing unit (CPU), or other programmable general-purpose or special-purpose microprocessor (Microprocessor), a digital signal processor (DSP), a programmable controller, an application specific integrated circuit (ASIC), a programmable logic device (PLD) or other similar devices or a combination of these devices, which can load and execute computer program related firmware or software to achieve access, calculation and control functions.

[0053] Specifically, the control circuit 110 is used to access a plurality of default reference tables D1-DM, where M is a positive integer greater than 1. The reference tables D1-DM are associated with resistance, temperature, and a threshold voltage value of each driving transistor 131-13N, and indicate the corresponding relationship between the aforementioned parameters.

[0054] In the present embodiment, the control circuit 110 is used to receive the sensing voltage Vout. The control circuit 110 is also used to generate a bias voltage Vbs according to the sensing voltage Vout based on a plurality of reference tables D1-DM, and to drive a plurality of driving transistors 131 to 13N according to the bias voltage Vbs. The bias voltage Vbs is, for example, a signal in an independent circuit for controlling each driving transistor 131 to 13N, and is, for example, a gate control signal. That is, each driving transistor 131 to 13N receives its own independent bias voltage Vbs.

[0055] It is worth mentioning that, since the sensing voltage Vout indicates the temperature change sensed by the thermistor 121, the control circuit 110 can obtain the resistance, temperature and critical voltage value corresponding to the sensing voltage Vout based on multiple reference tables D1-DM. Therefore, the control circuit 110 can further adjust the control signals (i.e., bias voltage Vbs) of the multiple driving transistors 131 to 13N according to the aforementioned multiple parameters (including the critical voltage value corresponding to the temperature change). In this way, the display device 100 can compensate for the temperature variation of the multiple driving transistors 131 to 13N according to its current temperature, and drive these driving transistors 131 to 13N with the compensated bias voltage Vbs, so as to avoid abnormal display of the display device 100.

[0056] Figure 2 is a circuit diagram of a sensing circuit according to an embodiment of the present invention. Figure 2 , the sensing circuit 220 can be applied in Figure 1 In the display device 100, the sensing circuit 220 is, for example, Figure 1 An implementation of the sensing circuit 120.

[0057] exist Figure 2 In an embodiment, the sensing circuit 220 is implemented by a voltage divider circuit, for example. The sensing circuit 220 includes a thermistor 221 and a second resistor 222. The thermistor 221 and the second resistor 222 are connected in series between the input voltage Vin and the reference voltage GND.

[0058] Specifically, a first terminal of the thermistor 221 receives an input voltage Vin. A second terminal of the thermistor 221 is coupled to a first terminal of a second resistor 222 at a voltage dividing node N1. A second terminal of the second resistor 222 receives a reference voltage GND. The reference voltage GND is, for example, a ground voltage.

[0059] In this embodiment, when the substrate (for example Figure 1 When the temperature of the substrate 101 shown in FIG. 1 changes (e.g., increases), the resistance value of the thermistor 221 changes accordingly. Therefore, the sensing circuit 220 can output a sensing voltage Vout at the voltage dividing node N1 through the design of a voltage dividing circuit to indicate the temperature change sensed by the thermistor 221, thereby indicating the current temperature change of the display device.

[0060] In this embodiment, the size of the thermistor 221 is, for example, less than 1 mm. In this embodiment, the thermistor 221 is, for example, disposed on the substrate in a bonding manner.

[0061] In the present embodiment, the material of the second resistor 222 includes polysilicon material. For example, the material of the second resistor 222 may be polysilicon materials such as indium gallium zinc oxide (IGZO), titanium (Ti) and aluminum (Al) compounds, and molybdenum (Mo) and aluminum compounds. The material of the second resistor 222 may also be a high-impedance transparent metal material. The second resistor 222 has a high resistance value (e.g., 10k ohms).

[0062] Figure 3 is a circuit diagram of a display device according to another embodiment of the present invention. Figure 3 The display device 300 includes a control circuit 310, at least one sensing circuit 320 and a plurality of pixel units, wherein Figure 3 A single pixel unit 350 is used as a schematic representation. Each pixel unit has the same circuit architecture. Various circuit components in each pixel unit have correspondingly the same specifications.

[0063] For reference Figure 4 , Figure 4 According to the present invention Figure 3 The circuit diagram of the pixel unit shown in the embodiment. Figure 4 In the embodiment, the pixel unit 350 includes a driving transistor 331 and a light emitting component 341. The control circuit 310, the sensing circuit 320, the driving transistor 331 and the light emitting component 341 can refer to the relevant description of the display device 100 and be deduced by analogy.

[0064] exist Figure 3 In the embodiment, the sensing circuit 320 includes a thermistor 321 (ie, resistor R1) and a second resistor 322 (ie, resistor R2). The thermistor 321 and the second resistor 322 can refer to the relevant description of the sensing circuit 220 and be deduced by analogy.

[0065] exist Figure 4 In the embodiment, the driving transistor 331 is implemented by a PMOSFET, for example. The light emitting element 341 is implemented by a micron light emitting diode (Micro LED), for example.

[0066] Specifically, the control terminal (i.e., gate terminal) of the driving transistor 331 receives the bias voltage Vbs. The first terminal (i.e., first source / drain terminal) of the driving transistor 331 is coupled to the cathode terminal of the light-emitting component 341. The second terminal (i.e., second source / drain terminal) of the driving transistor 331 receives the reference voltage VSS. The anode terminal of the light-emitting component 341 receives the reference voltage VDD. The reference voltage VSS is, for example, a low power supply voltage. The reference voltage VDD is, for example, a high power supply voltage.

[0067] In the present embodiment, the control circuit 310 is implemented by, for example, an integrated circuit or a microcontroller unit (MCU). The control circuit 310 includes a plurality of pins PN1 to PN4. The control circuit 310 is coupled to the first end of the thermistor 321 via the pin PN1 to provide an input voltage Vin. The control circuit 310 is coupled to the voltage dividing node N1 of the sensing circuit 320 via the pin PN2 to receive the sensing voltage Vout. The control circuit 310 is coupled to the second end of the second resistor 322 via the pin PN3 to provide a reference voltage GND. The control circuit 310 is coupled to the pixel unit 350 via the pin PN4 to provide a bias voltage Vbs.

[0068] In detail, in response to the temperature change of the display device 300, the sensing circuit 320 generates a sensing voltage Vout according to the input voltage Vin, so that the control circuit 310 receives the sensing voltage Vout through the pin PN2. In addition, the control circuit 310 calculates the sensing voltage Vout according to the input voltage Vin and the voltage division information corresponding to the thermistor 322 to obtain the sensing resistance value of the thermistor 322. The voltage division information indicates the voltage division state between the thermistor 321 and the second resistor 322, that is, the resistance value ratio indicated by the voltage divider rule.

[0069] In this embodiment, the calculation method of the sensing voltage Vout is represented by the following formula (1), for example. In the formula (1), Vout is the voltage value of the sensing voltage Vout, Vin is the voltage value of the input voltage Vin, R1 is the resistance value of the thermistor 321, and R2 is the resistance value of the second resistor 322.

[0070]

[0071] Since the second resistor 322 has a fixed high resistance value and the input voltage Vin has a fixed voltage value, the control circuit 310 calculates the sensing voltage Vout according to the voltage division information indicated by formula (1) (i.e., the resistance value ratio of R1 to R2) to obtain the sensing resistance value (i.e., R1) of the thermistor 321. The sensing resistance value of the thermistor 321 indicates the resistance value that the thermistor 321 has in response to the current temperature change.

[0072] Next, the control circuit 310 searches a first reference table (eg, Figure 1 In this embodiment, the first reference table includes the corresponding relationship between the resistance value and temperature of the thermistor 321. The first reference table can also be called a resistance value and temperature table (ie, RT table).

[0073] That is, as the temperature of the display device 300 changes (e.g., rises), the resistance value of the thermistor 321 changes accordingly. The control circuit 310 accesses the sensing voltage Vout on the voltage dividing node N1 and converts the sensing voltage Vout into a corresponding sensing resistance value. The control circuit 310 uses a lookup table (i.e., a first reference table) about the thermistor 321 to know the current temperature (i.e., the sensing temperature) at the location of the thermistor 321 according to the sensing resistance value.

[0074] In this embodiment, the control circuit 310 generates a control signal based on a second reference table (eg, Figure 1 Another reference table DN shown in FIG. 1 is used to calculate the offset voltage difference of each critical voltage value by sensing the temperature. In this embodiment, the second reference table includes the corresponding relationship between the temperature and each critical voltage value. The aforementioned critical voltage value includes the critical voltage value of the driving transistor 331. The second reference table can also be called an experimental data table of the temperature and the critical voltage value of the driving transistor.

[0075] It should be noted that since the threshold voltage value of each driving transistor (using the driving transistor 331 for example) varies with temperature, the control circuit 310 uses the second reference table to know in advance a plurality of threshold voltage values ​​of the driving transistor 331 under different temperature conditions.

[0076] That is, the control circuit 310 performs interpolation calculation on the sensed temperature according to the second reference table to obtain the critical voltage value corresponding to the sensed temperature. The control circuit 310 calculates the difference between the aforementioned critical voltage value and the default critical voltage value of the driving transistor 331 to obtain the variation (i.e., offset voltage difference) of the critical voltage value of the driving transistor 331. The default critical voltage value is, for example, the critical voltage value indicated in the specification of the driving transistor 331, or the current critical voltage value of the driving transistor 331 before the temperature changes.

[0077] Next, the control circuit 310 generates a bias voltage Vbs according to the offset voltage difference. For example, the control circuit 310 offsets the voltage currently used to drive the driving transistor 331 by a single offset voltage difference to obtain the bias voltage Vbs. That is, the bias voltage Vbs is a control signal after compensating for temperature changes.

[0078] In the present embodiment, the control circuit 310 outputs the bias voltage Vbs to each driving transistor (including the driving transistor 331) through the pin PN4. The driving transistor 331 drives the light-emitting element 341 to emit light based on the reference voltage VDD according to the bias voltage Vbs. In this way, even if the driving transistor 331 has a variable threshold voltage value due to temperature rise, the driving transistor 331 can operate according to the temperature-compensated bias voltage Vbs, thereby maintaining the grayscale value corresponding to the light-emitting element 341.

[0079] Figure 5 is a block diagram of a display device according to another embodiment of the present invention. Figure 5 The display device 500 includes a substrate 501, a control circuit (not shown), a plurality of sensing circuits 520-1 to 520-5, and a plurality of pixel units (not shown). The substrate 501, the control circuit, the plurality of sensing circuits 520-1 to 520-5, and the plurality of pixel units can refer to the relevant description of the display device 100 or the display device 300 and be deduced by analogy. The number of the plurality of sensing circuits 520-1 to 520-5 is only an example.

[0080] Compared to Figure 3 Example, in Figure 5 In the embodiment, the sensing circuits 520-1 to 520-5 are plural. The sensing circuits 520-1 to 520-5 are dispersedly disposed in the active region (not shown) of the substrate 501. Specifically, the plurality of thermistors (including, for example, Figure 3Thermistors 321 shown in the figure are respectively arranged at different positions of the substrate 501. In addition, these thermistors are arranged based on the center of the active area of ​​the substrate 501, and are arranged dispersedly from the aforementioned center to the surroundings of the active area. For example, multiple thermistors are respectively arranged at multiple positions of the diagonal lines of the substrate 501. Alternatively, with the intersection of two diagonal lines of the substrate 501 as the center, multiple thermistors have different distance radii relative to this center and are respectively arranged at multiple positions of the substrate 501.

[0081] It should be noted that, in response to various temperature variations at different locations of the display device 500, the resistance values ​​of the thermistors in the plurality of sensing circuits 520-1 to 520-5 are changed accordingly. Figure 3 The input voltage Vin shown in FIG. 1 generates a plurality of sensing voltages (including, for example, Figure 3 The sense voltage Vout shown).

[0082] Continuing with the above description, the control circuit is based on multiple reference tables (such as Figure 3 as well as Figure 4 The first reference table and the second reference table described in the embodiment) are used to generate a plurality of bias voltages corresponding to different positions according to a plurality of sensing voltages (including, for example, Figure 3 The control circuit drives a plurality of driving transistors corresponding to different positions according to the bias voltages.

[0083] Specifically, the control circuit obtains a plurality of sensing temperatures according to a plurality of sensing voltages output by a plurality of sensing circuits 520-1 to 520-5 based on the first reference table. The sensing temperatures respectively indicate various current temperature changes at different locations (or in different regions) of the display device 500.

[0084] Next, the control circuit calculates each sensed temperature based on the second reference table to obtain a corresponding offset voltage difference. The multiple offset voltage differences respectively indicate various variations of the threshold voltage values ​​of the multiple driving transistors, wherein the multiple driving transistors are respectively located at corresponding multiple positions (or, multiple regions). The control circuit generates multiple bias voltages according to the offset voltage differences, and outputs the bias voltages to the multiple driving transistors located at corresponding various positions (or, various corresponding regions).

[0085] That is, considering the temperature variation at different positions (or in different areas), by respectively setting a plurality of sensing circuits 520-1 to 520-5 at a plurality of positions, the display device 500 can compensate for the variation of a plurality of driving transistors at different positions due to various temperatures.

[0086] In summary, the display device of the embodiment of the present invention is based on multiple reference tables, and through the thermistors set on the substrate, it is possible to know the resistance, temperature and critical voltage value of the driving transistor corresponding to the sensing voltage. The control circuit can further compensate for the variation of the driving transistor caused by temperature according to the aforementioned multiple parameters (including the critical voltage value corresponding to the temperature change). In this way, the display device can drive multiple pixel units with a compensated bias voltage in response to its current temperature, thereby avoiding abnormal display images of the display device. In some embodiments, through multiple thermistors set at different positions, the display device can compensate for the variation of the corresponding driving transistor in response to temperature variations in different positions or regions.

[0087] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Any person having ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims

1. A display device, characterized in that: include: A plurality of driving transistors are disposed on a substrate to drive a plurality of light-emitting components; At least one sensing circuit, including a thermistor, is disposed on the substrate and is used to generate a sensing voltage according to an input voltage; as well as A control circuit is coupled to the plurality of driving transistors and the at least one sensing circuit, and is used to generate a bias voltage according to the sensing voltage based on a plurality of reference tables associated with resistance, temperature and a threshold voltage value of each of the driving transistors, and to drive the plurality of driving transistors according to the bias voltage.

2. The display device according to claim 1, characterized in that The control circuit is also used to: The sensing voltage is calculated according to the input voltage and voltage division information corresponding to the thermistor to obtain a sensing resistance value of the thermistor.

3. The display device according to claim 2, characterized in that The control circuit is used to: According to the sensed resistance value, searching a first reference table in the plurality of reference tables to obtain a sensed temperature; Based on a second reference table in the plurality of reference tables, calculating the sensed temperature to obtain an offset voltage difference for each of the threshold voltage values; as well as The bias voltage is generated according to the offset voltage difference.

4. The display device according to claim 3, characterized in that The first reference table includes a corresponding relationship between the resistance value of the thermistor and the temperature, and the second reference table includes a corresponding relationship between the temperature and each of the critical voltage values.

5. The display device according to claim 1, characterized in that The sensing circuit also includes a second resistor. The first end of the thermistor receives the input voltage, the second end of the thermistor is coupled with the first end of the second resistor to output the sensing voltage, and the second end of the second resistor receives a reference voltage.

6. The display device according to claim 5, characterized in that The material of the second resistor includes polysilicon material.

7. The display device according to claim 1, characterized in that The thermistor is disposed on the substrate in a bonding manner.

8. The display device according to claim 1, characterized in that The at least one sensing circuit is multiple in number, and the multiple thermistors in the multiple sensing circuits are respectively disposed at different positions of the substrate.

9. The display device according to claim 8, characterized in that The multiple sensing circuits respectively generate multiple sensing voltages according to the input voltage, so that the control circuit generates multiple bias voltages corresponding to different positions according to the multiple sensing voltages based on the multiple reference tables, and drives the corresponding multiple driving transistors according to the multiple bias voltages.

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