CN108022554A - brightness control device of display device and related method - Google Patents

Abstract

The invention provides a brightness control device of a display device and a related method. The brightness control device is used in a display device and comprises a gain value generating circuit, a numerical value adjusting circuit and a gamma converting circuit. The gain value generating circuit generates a gain value according to at least one brightness setting value corresponding to the display device. The value adjusting circuit is coupled to the gain value generating circuit and used for receiving the input value and adjusting the input value according to the gain value to generate an output value. The gamma conversion circuit is coupled to the value adjustment circuit and is used for carrying out gamma conversion on the output value according to a specific gamma value to generate a converted value, wherein the display device is driven based on the converted value.

Description

Brightness control device and related method of display device

technical field

The invention relates to a display device, in particular to a device and a related method for controlling screen brightness.

Background technique

The brightness adjustment mechanism of the screen of an active-matrix organic light-emitting diode (AMOLED) display device is usually implemented in the following two ways. First, a circuit switch is set in each cell in the panel, through which the pixel current is controlled to change the brightness. However, since the switches are affected by variations in the manufacturing process, resulting in individual differences between switches, there is a problem of uneven or inaccurate brightness. Second, a digital gamma correction (digital gamma correction) circuit is used to adjust the numerical value of the input image data, so as to achieve the effect of adjusting brightness. If a digital gamma correction circuit is used to adjust the brightness, the digital gamma correction circuit needs to store multiple sets of look-up tables (LUTs) corresponding to different brightness adjustment results, and this method has the following defects. First of all, the number of levels of brightness adjustment will be limited by the number of LUTs. That is to say, if you want to accurately control the brightness of the screen, you must store a set of LUTs for each level of brightness adjustment, but this will increase the number of digital gamma correction circuits. storage burden. In addition, these LUTs corresponding to different luminances also need to be corrected for the standard gamma value of 2.2, which increases the complexity of gamma correction and leads to a larger digital gamma correction circuit.

It can be seen that there are defects in the existing brightness control mechanism for active matrix organic light emitting diode display devices.

Contents of the invention

In order to solve the shortcomings of the brightness control mechanism in the existing display device, the purpose of the present invention is to provide an innovative screen brightness control method. Wherein, the present invention directly adjusts the numerical value of the input image data, so that the driving circuit drives the panel with the adjusted numerical value, so as to achieve the effect of brightness adjustment. The feature of this method is that the input value is adjusted before the digital gamma correction is performed, so the existing digital gamma correction circuit does not require additional changes, and it will not be as flexible and accurate as the existing technology. degree is limited by the digital gamma correction circuitry.

An embodiment of the present invention provides a brightness control device used in a display device. The brightness control device includes: a gain value generation circuit, a value adjustment circuit and a gamma conversion circuit. The gain value generation circuit generates a gain value according to at least one brightness setting value corresponding to the display device. The value adjustment circuit is coupled to the gain value generating circuit, and is used for receiving the input value, and adjusting the input value according to the gain value to generate an output value. The gamma conversion circuit is coupled to the value adjustment circuit, and is used for performing gamma conversion on the output value according to a specific gamma value to generate a converted value, wherein the display device is driven based on the converted value.

Another embodiment of the present invention provides a brightness control method used in a display device. The method includes: determining a gain value according to at least one brightness setting value corresponding to the display device; adjusting the input value according to the gain value to generate an output value; performing gamma conversion on the output value based on a specific gamma value to generate a converted value; and driving the display device according to the converted value.

Description of drawings

FIG. 1 is a structural diagram of an embodiment of a brightness control device of the present invention.

Fig. 2 is a flowchart of an embodiment of the method of the present invention.

Description of reference symbols

100 brightness control device

110 gain value generating circuit

120 value adjustment circuit

112 parameter calculation unit

114 gain calculation unit

130 gamma conversion circuit

220 drive circuit

230 panels

300 display devices

Detailed ways

Certain terms are used throughout the specification and following claims to refer to particular elements. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This description and the following claims do not use the difference in name as the way to distinguish components, but the difference in function of the components as the criterion for distinguishing. The term "comprising" mentioned throughout the specification and subsequent claims is an open term, so it should be interpreted as "including but not limited to". In addition, the term "coupled" herein includes any direct and indirect means of electrical connection. Therefore, if it is described that a first device is coupled to a second device, it means that the first device may be directly electrically connected to the second device, or indirectly electrically connected to the second device through other devices or connection means.

Please refer to FIG. 1 , which is a structural diagram of an embodiment of a brightness control device of the present invention. As shown in the figure, the brightness control device 100 of the present invention is used in a display device 300 to realize screen brightness control. The brightness control device 100 processes the input value DI corresponding to the input image data to generate an output value DO. The output value DO is converted by gamma to generate the converted value Dgamma. The driving circuit 220 provides an appropriate current to drive a pixel in the panel 230 according to the converted value Dgamma. Please note that the input value DI mentioned in this specification refers to the brightness value (ie, the gray scale value) corresponding to one pixel in the panel 230 . Although the following description only deals with the processing of a single input value DI; however, those skilled in the art should understand that in order to control the overall screen brightness of the display device 300, the brightness control device 100 may simultaneously control multiple input values corresponding to different pixels. The value DI is processed to generate a plurality of output values DO. In addition, although the present invention does not limit the type of display device to which the brightness control device 100 is applicable, in a preferred embodiment, the display device 300 can be an active-matrix organic light-emitting diode (Active-matrix organic light-emitting diode, AMOLED) display device.

The brightness control device 100 includes a gain value generation circuit 110 , a value adjustment circuit 120 and a gamma conversion circuit 130 . The gain value generation circuit 110 is used to determine the gain value BL_gain, and the value adjustment circuit 120 adjusts the input value DI according to the gain value BL_gain determined by the gain value generation circuit 110 to generate the output value DO. Finally, the output value DO will be sent to the gamma conversion circuit 130 . The gamma conversion circuit 130 performs gamma conversion on the output value DO based on a specific gamma value (eg, 2.2) to generate a converted value Dgamma. The gain generating circuit 110 includes a parameter calculation unit 112 and a gain calculation unit 114 . The parameter calculation unit 112 is configured to determine a gain parameter according to at least one brightness setting value corresponding to the display device 300 , and the gain calculation unit 114 calculates a gain value BL_gain based on the gain parameter determined by the parameter calculation unit 112 .

In an embodiment, the parameter calculation unit 112 determines the gain parameter according to a brightness setting value Bconfig1 corresponding to the display device 300 . For example, when the user sets the brightness setting value of the display device 300 to 50% of the maximum brightness, the parameter calculation unit 112 can determine the gain parameter BL_duty1 to be 1/2 according to the brightness setting value, and the gain parameter BL_duty1 Will be further used as the gain value BL_gain. That is to say, when the display device 300 is only affected by one brightness setting value Bconfig1, the gain parameter BL_duty1 can be directly used as the gain value BL_gain.

In addition, in some applications, the brightness of the display device 300 may not only be changed through user settings, but may also have an internal automatic adjustment mechanism, for example, based on automatic brightness adjustment based on ambient brightness. In this case, the display device 300 corresponds to two brightness setting values Bconfig1 and Bconfig2. For example, the user sets the brightness of the display device 300 to 50% of the maximum brightness (Bconfig1), and the automatic adjustment mechanism of the environment brightness can adjust the brightness of the display device 300 to the maximum brightness (the maximum brightness that can be adjusted by the user ) of 25% (Bconfig2). Accordingly, the parameter calculation unit 112 respectively determines the first gain parameter BL_duty1 to be 1/2 and the second gain parameter BL_duty2 to be 1/4 based on the brightness setting values Bconfig1 and Bconfig2. Next, the gain calculation unit 114 determines the gain value BL_gain according to the first gain parameter BL_duty1 and the second gain parameter BL_duty2. Preferably, the gain calculation unit 114 is a multiplication circuit, which can multiply the first gain parameter BL_duty1 and the second gain parameter BL_duty2, so as to determine the gain value BL_gain as (1/2)x(1/4)=1/8 .

The gain value BL_gain obtained through the above process will be further sent to the value adjustment circuit 120 . The value adjustment circuit 120 adjusts the input value DI according to the gain value BL_gain to generate the output value DO. Preferably, the value adjustment circuit 120 is a multiplication circuit, which can multiply the gain value BL_gain by the input value DI to generate an adjusted value DO.

In addition, the brightness adjustment of the display device 300 can also adjust the gain value BL_gain multiple times within a certain time interval through the gain value generation circuit 110 to achieve a gradual brightness change effect. For example, when the brightness setting value of the display device 300 is to be adjusted from 80% to 50% (based on user settings or an automatic adjustment mechanism), then the gain value generating circuit 110 first provides a gain value BL_gain of 0.8 (For example: the parameter calculation unit 112 generates the first gain parameter BL_duty1=0.8, and the second gain parameter BL_duty2=1), and after a specific time interval, for example, after a frame period (frame period), a gain value of 0.65 is generated The value BL_gain (for example: the parameter calculation unit 112 generates the first gain parameter BL_duty1=0.65, and the second gain parameter BL_duty2=1). Then, when the above-mentioned specific time interval passes again, the gain value generation circuit 110 will generate a gain value BL_gain of 0.5 (for example: the parameter calculation unit 112 generates the first gain parameter BL_duty1=0.5, and the second gain parameter BL_duty2=1 ). In this way, gradual screen brightness adjustment of the display device 300 can be realized. During the above adjustment process, the gain value generation circuit 110 can determine the timing of switching the value of the gain value BL_gain according to the synchronization signal (such as V-Sync) provided by the external circuit. In addition, this gradual brightness adjustment method can also be used when the brightness setting of the display device 300 is increased, and can be divided into more stages (for example: 0.8 0.7 0.6 0.5). In addition, the two gain parameters BL_duty1 and BL_duty2 can also be adjusted progressively at the same time.

The gamma conversion circuit 130 may store multiple sets of LUTs corresponding to different gamma values, so as to perform gamma correction on the brightness-adjusted result (output value DO) based on different gamma values. Under normal circumstances, the gamma conversion circuit 130 only performs gamma conversion on the output value DO based on the standard gamma value of 2.2. However, in some special cases, the gamma conversion circuit 130 may perform gamma conversion on the output value DO based on a value other than the gamma value 2.2. In addition, although the gamma conversion circuit 130 of the present invention may store multiple sets of LUTs, it is different from the prior art in that the gamma conversion circuit 130 only needs to store one set of LUTs for one brightness setting, so the two are comparable in number There is a considerable difference in .

The above operations of the brightness control device 100 can be summarized into the flow chart of FIG. 2 . As shown in the figure, in step 21, a gain value is provided according to at least one brightness setting value. Next, in step 22, the input value is adjusted according to the gain value to generate an output value. And, in step 23, gamma conversion is performed according to the output value to generate a converted value. Finally, in step 24, the display device is driven according to the converted value. Since the principle and operation details of the brightness control device 100 have been introduced in detail in the previous paragraphs, steps 21 to 24 are not repeatedly described here for the sake of brevity.

In summary, the brightness adjustment mechanism of the present invention directly adjusts the input value instead of changing the screen brightness through gamma conversion, so it can save or reduce the hardware cost and complexity of the gamma correction circuit under the existing architecture. In addition, since the order of brightness adjustment is no longer limited by the number of LUTs, the brightness adjustment and control are more precise and flexible.

The "embodiment" mentioned above means that the specific features, structures or characteristics described for the embodiment are included in at least one implementation of the present invention. Therefore, "embodiments" appearing in different paragraphs of the text do not represent the same embodiment. Therefore, although different structural features or methodological actions are mentioned in the above descriptions of different embodiments, it should be noted that these different features can be simultaneously implemented in the same specific implementation through appropriate modifications.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention shall fall within the scope of the present invention.

Claims (14)

1. a kind of brightness controlling device being used in display device, comprising：

Yield value generation circuit, according to the corresponding at least one brightness settings of the display device, determines yield value；

Numerical value adjustment circuit, is coupled to the yield value generation circuit, to receive the input numerical value, and is adjusted according to the yield value Numerical value is inputted, produces output numerical value；And

Gamma conversion circuit, is coupled to the numerical value adjustment circuit, according to specific gamma value, which is carried out gamma Conversion, produces numerical value after conversion, and the wherein display device is driven according to numerical value after the conversion.

2. brightness controlling device as claimed in claim 1, wherein the yield value generation circuit according to the brightness settings and Ratio between the corresponding upper limit value of the brightness settings, determines the yield value.

3. brightness controlling device as claimed in claim 1, wherein the yield value generation circuit in time interval in repeatedly adjusting The yield value, makes the yield value be adjusted by initial value to the numerical value determined.

4. brightness controlling device as claimed in claim 1, wherein the yield value generation circuit include：

Parameter calculation unit, to according to the between corresponding with first brightness settings upper limit value of the first brightness settings One ratio, determines the first gain parameter；And according to the second brightness settings upper limit value corresponding with second brightness settings Between the second ratio, determine the second gain parameter；And

Gain calculating unit, is coupled to the parameter calculation unit, to according to first gain parameter and second gain ginseng Number calculates the yield value.

5. brightness controlling device as claimed in claim 1, wherein first brightness settings correspond to the use of the display device Family brightness settings, and second brightness settings correspond to the auto brightness setting of the display device.

6. brightness controlling device as claimed in claim 1, the wherein display device show for active matrix organic light-emitting diode Showing device.

7. brightness controlling device as claimed in claim 1, wherein the gamma conversion circuit can be based on multiple and different gamma values Gamma conversion is carried out, and the gamma conversion circuit carries out gamma based on one in the plurality of gamma value to the output numerical value Conversion.

8. a kind of method for being used in display device carry out brilliance control, comprising：

According to the corresponding at least one brightness settings of the display device, yield value is determined；

The input numerical value is adjusted according to the yield value, produces output numerical value；

Based on specific gamma value, gamma conversion is carried out to the output numerical value, produces numerical value after conversion；And

The display device is driven according to numerical value after the conversion.

9. method as claimed in claim 8, wherein the step of determining the yield value according at least one brightness settings is wrapped Contain：

According to the ratio between brightness settings upper limit value corresponding with the brightness settings, the yield value is determined.

10. method as claimed in claim 8, wherein the step of providing the yield value according at least one brightness settings is wrapped Contain：

In in time interval, the yield value is repeatedly adjusted, the yield value is adjusted by initial value to the numerical value determined.

11. method as claimed in claim 8, wherein the step of determining the yield value according at least one brightness settings is wrapped Contain：

According to the first ratio between the first brightness settings upper limit value corresponding with first brightness settings, the first increasing is determined Beneficial parameter；

According to the second ratio between the second brightness settings upper limit value corresponding with second brightness settings, the second increasing is determined Beneficial parameter；And

The yield value is calculated according to first gain parameter and second gain parameter.

12. user's brightness that method as claimed in claim 8, wherein first brightness settings correspond to the display device is set It is fixed, and second brightness settings are corresponding to the auto brightness setting of the display device.

13. method as claimed in claim 8, the wherein display device are active matrix organic light-emitting diode display device.

14. method as claimed in claim 8, wherein carrying out the step of gamma conversion to the output numerical value based on the specific gamma value Suddenly include：

One is selected from multiple gamma values, and gamma conversion is carried out to the output numerical value based on selected gamma value.