KR101149216B1 - Display apparatus and control method thereof - Google Patents

Abstract

A display device according to an exemplary embodiment of the present invention is a display device including: an illuminance sensing unit for sensing an illuminance of a periphery of the display device; A memory unit storing an equation corresponding to each illumination level group divided into a predetermined number of groups; And a controller for extracting an equation corresponding to the illumination sensing state of the illumination sensing unit and setting a register value for adjusting a luminance level of the display device using the extracted equation, (Unified Glare Rating) value is less than a specific level, based on the luminance level of the display device according to the illumination sensing state.

Illuminance, average luminance level, UGR

Description

[0001] The present invention relates to a display apparatus and a control method thereof,

The present invention relates to a display device, and more particularly, to a display device and a control method thereof that can realize an appropriate luminance in consideration of a brightness level of an input image data and a brightness of an ambient illuminance.

In general, since the maximum brightness that can be expressed for each image display device is determined, the contrast ratio to be displayed is also determined. Therefore, in the current image display device, various techniques are used to adjust the brightness information of the screen to improve the hue contrast, but for practical reasons, the effect is not significant.

A typical method is to adjust the brightness of the screen using the average value of the video signal. In this method, the maximum brightness of the screen is controlled by an APL (Auto Peak Limit) circuit using the average brightness of the screen.

As shown in FIG. 1, the APL control method is briefly described. In the entire image, the average brightness level is high, so that the maximum brightness is controlled to be dark. When the brightness of the whole image is dark, So that the average brightness of the image is kept constant.

Also, in recent years, a method of adjusting the brightness of the screen according to the surrounding brightness level of the display device has also been provided.

That is, as shown in FIG. 2, the ambient brightness of the display device is measured and the brightness of the screen of the display screen is adjusted according to the measured ambient brightness. At this time, if the measured ambient brightness level is relatively high, And when the measured ambient brightness level is relatively low, the brightness of the display screen is lowered, thereby relieving fatigue of the eyes.

In the embodiment of the present invention, the brightness level that can alleviate the fatigue of the eyes of the viewer can be automatically set according to the illuminance of the surroundings and the level of the input data provided on the display device.

It is to be understood that the technical objectives to be achieved by the embodiments are not limited to the technical matters mentioned above and that other technical subjects not mentioned are apparent to those skilled in the art to which the embodiments proposed from the following description belong, It can be understood.

A display device according to an exemplary embodiment of the present invention is a display device including: an illuminance sensing unit for sensing an illuminance of a periphery of the display device; A memory unit storing an equation corresponding to each illumination level group divided into a predetermined number of groups; And a controller for extracting an equation corresponding to the illumination sensing state of the illumination sensing unit and setting a register value for adjusting a luminance level of the display device using the extracted equation, (Unified Glare Rating) value is less than a specific level, based on the luminance level of the display device according to the illumination sensing state.

According to another aspect of the present invention, there is provided a method of controlling a display device, the method comprising: obtaining an equation having an average brightness level and a register value as variables, such that the UGR value is less than a specific level step; Sensing ambient illumination of the display device; And setting a register value according to an average luminance level of the input image data by applying an equation according to the sensed ambient illuminance.

The display device and the control method thereof according to the embodiment of the present invention automatically provide an appropriate brightness level according to the illuminance of the surroundings and the level of the input data of the display device, It has the effect of relieving eye fatigue.

The proposed embodiment will be described.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. It should be understood, however, that there is no intention to limit the scope of the present invention to the embodiment shown, and other embodiments which are degenerative by adding, changing or deleting other elements or other embodiments falling within the spirit of the present invention Can be proposed.

Although the term used in the present invention is a general term that is widely used at present, there are some terms selected arbitrarily by the applicant in a specific case. In this case, since the meaning is described in detail in the description of the corresponding invention, It is to be understood that the present invention should be grasped as a meaning of a non-term.

That is, in the following description, the word 'comprising' does not exclude the presence of other elements or steps than those listed.

FIG. 3 is a diagram illustrating a configuration of a display device according to an embodiment of the present invention.

3, a display device according to an embodiment of the present invention includes a memory unit 100, an illumination sensing unit 101, a video data receiving unit 102, an average luminance level detection unit 103, and a control unit 104 .

The memory unit 100 stores programs related to the operation of the display apparatus and various data generated during operation of the display apparatus.

In addition, the memory unit 100 stores the equation for each illuminance group obtained corresponding to the product model information of the display device.

The above equation is obtained on the basis of the display device luminance level according to the illumination sensing state for reducing the UGR (Unified Glare Rating) value to less than a specific level.

Also, the equation is a linear equation consisting of a first variable indicating an average luminance level, a and a, b being coefficients of the first variable, and a solution obtained through the linear equation (second variable) And is set to a register value for adjusting the level.

The first equation may include first coordinate information including a register value and a minimum average luminance level value corresponding to a maximum average luminance level belonging to the same group from the display apparatus luminance level according to the illumination sensing state, And the second coordinate information made up of the maximum average brightness level value.

The process of obtaining the above equation will be described in detail below.

The memory may be implemented as a nonvolatile memory capable of updating and erasing data, for example, an EEPROM (Electrically Erasable Programmable Read Only Memory) and / or an EDID ROM (Extended Display Identification Data ROM) And is connected to the control unit 104.

The illuminance sensing unit 101 senses the illuminance of the surroundings where the display device is installed. That is, the illuminance sensing unit 101 includes a photosensor to convert an external light signal into an electrical signal, and measures the electrical signal to sense an external illuminance.

The video data receiving unit 102 receives video data input from the outside and outputs the video data. Here, the video signal source for providing the video signal may be a PC (not shown), and the video data receiving unit 102 may be a D-sub connection interface connected to the video signal source. Here, the input video signal includes R, G, B video signals and H / V synchronization signals.

In addition, the image data receiving unit 102 may be implemented as a tuner, a set-top box, an HDMI interface, and a wireless communication module.

The average luminance level detector 103 measures the average pixel level (APL) of the image data input through the image data receiver 102.

That is, the video signal input through the video data receiving unit 102 is output to the average brightness level detector 103. Then, the average brightness level detector 103 measures the APL corresponding to each frame of the input image data. Then, the measured APL is transmitted to the control unit 104.

Here, the APL corresponds to one of the image characteristic quantities for the image data, and the brightness level control of the display device according to the measured APL is performed based on the equation.

The control unit 104 extracts an equation corresponding to the sensed illumination sensing state from the illumination unit 101 from the memory unit 100. A register value for controlling the brightness level of the display device is set by substituting the APL value detected through the average brightness level detector 103 into the extracted equation.

Hereinafter, the process of obtaining the above equation and the operation of the control unit 104 will be described in more detail.

Generally, architectural academy uses UGR (Unified Glare Rating) system to grasp the degree of discomfort.

The UGR system generally represents an offensive discharge value of between 10 and 30. At this time, as the UGR value decreases, the unpleasantity luminance decreases. As the UGR value increases, the unpleasant luminance increases.

In addition, the UGR may be integrated with all the light sources, or may be evaluated by a point light source.

The basic formula of the UGR is as follows.

The UGR value obtained through Equation (1) is evaluated by a Glare Criteria. The performance criteria are as follows.

Mean Response UGR Just Imperceptible 10 Perceprible 16 Acceptable (Just Acceptible) 19 Inacceptible 22 Just Uncomfortable 25 Uncomfortable 28 Just intolerable 31

That is, when the UGR value exceeds 10, it may not only cause inconvenience to viewers but also cause eye fatigue.

Therefore, in the present invention, the brightness level of the display device according to the ambient illuminance is set using the UGR value between 9 and 10 as a target.

In order to do this, it is first necessary to overlook how the UGR value changes in accordance with the illuminance of the surroundings where the display device is installed.

If the variation of the UGR value according to the ambient illuminance is overlooked, the brightness level of the display device having the UGR value between 9 and 10 is obtained according to the ambient illuminance.

illumination background
illumination monitor
luminance (Ls) W UGR 700 350 300 0.3225 10.53 690 345 296 0.3225 10.49 680 340 290 0.3225 10.45 670 335 288 0.3225 10.40 660 330 284 0.3225 10.36 650 325 280 0.3225 10.31 640 320 276 0.3225 10.27 630 315 272 0.3225 10.22 620 310 268 0.3225 10.17 620 305 264 0.3225 10.12 600 300 260 0.3225 10.07 590 295 256 0.3225 10.03 580 290 250 0.3225 9.92 570 285 248 0.3225 9.92 560 280 244 0.3225 9.87 550 275 240 0.3225 9.82 540 270 236 0.3225 9.77 530 268 232 0.3225 9.71 520 260 228 0.3225 9.66 510 255 224 0.3225 9.60 500 250 220 0.3225 9.55 490 245 218 0.3225 9.55 480 240 216 0.3225 9.56 470 235 214 0.3225 9.57 460 230 212 0.3225 9.58 450 225 210 0.3225 9.59 440 220 208 0.3225 9.60

That is, as shown in Table 2, when the ambient illuminance is 640, the luminance value of the display device should be 276 in order to set the UGR value to 10.27.

w = emission area / (distance * distance)

상기 수학식 3은 구스(Guth)의 위치지수이며, 변수의 정의는 아래와 같다.
p : 구스(Guth)의 위치지수
d : R/H
s : T/H
R,H,T : 도 4 참조

Equation (3) is the position index of Guth, and the definition of the variable is as follows.
p: position index of Guth
d: R / H
s: T / H
R, H, T: see Figure 4

In this case, in order to obtain the UGR value using Equation (1), w and p values should be calculated using Equation (2) and Equation (3).

The w value may vary depending on the model of the display device. That is, since the w value varies according to the inch information of the display device, the equation needs to be calculated differently according to the model information of the display device. Hereinafter, a model of 22 inches will be described as an example.

When the display device is 22 inches, the lateral length is 43 cm and the vertical length is 27 cm, so that the light emitting area is (0.43 * 0.27) m ² . In addition, since the viewing distance of the user is generally about 60 cm, the w value is obtained by using it. However, it should be apparent to those skilled in the art that the present invention is not limited thereto and that the brightness level of the display device can be adjusted by applying different equations according to the viewing distance of the user.

Accordingly, when the display device is 22 inches, the w value becomes 0.3225.

When the p value is obtained using Equation (3), H, T and R values as shown in FIG. 4 should first be obtained.

However, since the center of the light emitting area of the display device is generally horizontal with respect to the observer under normal viewing conditions, the H and T values become zero. Accordingly, as shown in FIG. 5, when the H value and the T value are 0, the T / R and H / R values become 0, so that the p value becomes 1. [

When the w value, the p value, and the illuminance level (L _b ) obtained in this manner are substituted into the equation (1), and the UGR value serving as the target is substituted into the left term, the Ls value of the display device luminance level corresponding thereto can be obtained .

In the embodiment of the present invention, a certain number of illumination levels may be grouped into one group, and a brightness level of the display device to be applied to each group may be set to Obtain the equation for setting.

That is, if the illuminance levels from 560 to 510 are grouped into one group, the luminance level of the applied display device is within the range of 244 to 224.

In other words, if the currently sensed ambient illuminance falls within the range of 560 to 510, the luminance level of the display device is changed only within the range of 224 to 244.

At this time, since the luminance level of the display device can not be changed at random in the luminance level variable range of the display device, the luminance level of the display device is varied in inverse proportion to the APL value of the input image data.

At this time, in order to vary the brightness level of the display device in inverse proportion to the APL value, an equation for setting the display device brightness level corresponding to the APL value should be obtained.

On the other hand, since the brightness level of the display device substantially checks the brightness level emitted from the outside of the display device, it can not be a practical application data value.

Therefore, a register value corresponding to the display device luminance level must exist.

The relation between the display device luminance level and the register value is as follows.

Register Luminance 255 244 254 244 253 242 252 240 251 238 250 236 249 234 248 232 247 230 246 228 245 226 244 224 243 222

As shown in Table 3, in order for the display device to set the luminance level to 244, the register value should be set to 255 or 254. Here, the register value is included in the range of 0 to 255. If the register value is set to 245, the backlight current value corresponding to the brightness level of the display device is provided to be 226.

Therefore, the above equation is an equation for obtaining a register value, which includes a variable for an average level of input image data.

Hereinafter, a method for obtaining the above equation will be described in detail.

As shown in Table 2, after the display device luminance level to be applied is obtained according to the illumination level, a certain range of illumination levels is grouped into one group.

For example, the illuminance levels in the range of 560 to 510 are grouped into one group, and the illuminance levels in the range of 500 to 440 are grouped into one group.

If a certain range of illumination levels is grouped into one group, the corresponding equation is obtained for each group. Hereinafter, the first group of illuminance levels in the range of 560 to 510 will be described.

In the case of the first group, the display device luminance level that can be represented is within the range of 224 to 244. In other words, if the current illumination level is 550, the display device luminance level should be varied within the range of 224 to 244.

At this time, in the embodiment of the present invention, the luminance level of the display device is varied in inverse proportion to the APL of the input image data.

On the other hand, in general, a method of obtaining an equation can be obtained by knowing two or more coordinate values. Therefore, in order to obtain an equation corresponding to the first group, two coordinate values must be obtained.

In order to obtain the coordinate value, a register value corresponding to a maximum value of a display device luminance level belonging to the first group, a register value corresponding to a minimum value, and a maximum APL and a minimum APL of input image data should be known.

In this case, the APL of the input image data is expressed in the range of 0 to 255 in general. However, since the level representation is meaningless within the range of 0 to 60 and 230 to 255, the display device luminance level is adjusted only within the range of 61 to 229.

Accordingly, the maximum value of the display device luminance level is 244 and the minimum value thereof is 224, so that the register value corresponding to the maximum value of the display device luminance level is 255, and the register value corresponding to the minimum value is 244. Also, the maximum APL is 230 and the minimum APL is 60.

6, since the y-axis is the register value and the x-axis is the APL value, and the relationship between the two values is in inverse proportion, the one coordinate value becomes (60, 255) The value becomes (230, 244).

y = ax + b

Since the general linear equation is as shown in Equation (4), the obtained two coordinate values are respectively substituted into Equation (4), and the a value and the b value are calculated accordingly.

In this way, the equation for the first group is y = (- 11/170) x + 258.88 as shown in FIG.

 Likewise, equations for different groups can be obtained, respectively. For example, when the coordinate values are (60, 149), (230, 125) as shown in FIG. 7, an equation such as y = (- 11/170) x + 123.88 is obtained.

Model illumination (Lux) Equation (x = APL, y = register)




W1953T



More than 680  y = 255 640 to 680  y = (- 11/170) x + 255.88 570-639  y = (- 11/170) x + 246.88 500 to 639  y = (- 11/170) x + 220.88 430 ~ 499  y = (- 11/170) x + 199.88 350 ~ 429  y = (- 11/170) x + 187.88 270 ~ 349  y = (- 11/170) x + 175.88 170 ~ 269  y = (- 11/170) x + 162.88 110 ~ 169  y = (- 11/170) x + 140.88 0 to 109  y = (- 11/170) x + 122.88




W1954TQ



More than 680  y = 255 640 to 680  y = (- 11/170) x + 258.88 570-639  y = (- 11/170) x + 246.88 500 to 639  y = (- 11/170) x + 232.88 430 ~ 499  y = (- 11/170) x + 216.88 350 ~ 429  y = (- 11/170) x + 206 270 ~ 349  y = (- 11/170) x + 193 170 ~ 269  y = (- 11/170) x + 177.88 110 ~ 169  y = (- 11/170) x + 157.88 0 to 109  y = (- 11/170) x + 135.88




W2253TQ



More than 680  y = 255 640 to 680  y = (- 11/170) x + 258.88 570-639  y = (- 11/170) x + 246.88 500 to 639  y = (- 11/170) x + 232.88 430 ~ 499  y = (- 11/170) x + 216.88 350 ~ 429  y = (- 11/170) x + 205 270 ~ 349  y = (- 11/170) x + 192 170 ~ 269  y = (- 11/170) x + 175.88 110 ~ 169  y = (- 11/170) x + 153.88 0 to 109  y = (- 11/170) x + 134.88




W2254TQ



More than 680  y = 255 640 to 680   y = 255 570-639  y = (- 11/170) x + 258.88 500 to 639  y = (- 11/170) x + 237.88 430 ~ 499  y = (- 11/170) x + 212.88 350 ~ 429  y = (- 11/170) x + 198 270 ~ 349 y = (- 11/170) x + 184 170 ~ 269 y = (- 11/170) x + 167.88 110 ~ 169 y = (- 11/170) x + 146.88 0 to 109 y = (- 11/170) x + 123.88

Equations according to the model names of the respective display devices can be obtained as described in Table 4 above.

Accordingly, the control unit 104 extracts an equation corresponding to the sensed illumination sensed by the illumination sensing unit 101 from the memory unit 100.

The controller 104 calculates a register value according to the APL detected through the average brightness level detector 103 using the extracted equation and applies the calculated register value to the brightness level of the display device .

As described above, the display device according to the embodiment of the present invention automatically provides an appropriate brightness level in accordance with the illuminance of the surroundings and the level of the input data provided in the display device, thereby providing a user with an optimal image quality, Can relieve the fatigue of.

FIG. 8 is a flowchart illustrating a method of controlling a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 8, a method of controlling a display device according to an exemplary embodiment of the present invention first calculates and stores an equation corresponding to a luminance level of a display device for each illumination level, such that the UGR value is less than a specific level (S101). Here, the method of obtaining the above equation will be described in more detail with reference to FIG. 9 below. The method for obtaining the above equations is described in detail in the description of the apparatus.

Next, the illuminance of the surroundings of the display device is sensed (S102).

Then, an equation corresponding to the sensed ambient illuminance is extracted from the stored equations (S103).

Next, the average luminance level of the input image data is detected (S104).

Then, the detected average brightness level is substituted into the extracted equation (S105). That is, the detected average brightness level is substituted into the X value of the extracted equation.

Next, a register value which is a y value is obtained through an operation according to the above average brightness level assignment (S106).

Then, the brightness level of the display device is adjusted by applying the calculated register value (S107).

9 is a flowchart for explaining a stepwise method of obtaining an equation according to an embodiment of the present invention.

Referring to FIG. 9, a method for obtaining an equation according to an exemplary embodiment of the present invention first determines a brightness level of a display device for each illumination level (Step S201) such that the UGR value is less than a specific level.

Then, a certain range of illumination levels is grouped into one group (S202).

Then, the maximum value and the minimum value of the brightness level of the display device existing in the same group are checked (S203) by referring to the same group in the group.

Next, the maximum value and the minimum value of the APL that can be expressed by the input image data are confirmed (S204).

The register value corresponding to the maximum value of the brightness level of the display device and the register value corresponding to the minimum value are checked (S205).

Next, the first coordinate information including the register value corresponding to the maximum value and the minimum APL, and the second coordinate information including the register value corresponding to the minimum value and the maximum APL are checked (S206).

Then, an equation corresponding to the first coordinate information and the second coordinate information is obtained (S207).

As described above, the control method of the display device according to the embodiment of the present invention automatically provides an appropriate brightness level according to the illuminance of the surroundings and the level of the input data provided in the display device, It can also relieve eye fatigue.

1 is a diagram for explaining a brightness level adjusted based on APL according to the prior art;

Fig. 2 is a diagram for explaining a brightness level adjusted based on the illuminance according to the related art; Fig.

3 is a diagram illustrating a configuration of a display device according to an embodiment of the present invention.

4 and 5 are diagrams for explaining a method of calculating a UGR value according to an embodiment of the present invention;

6 and 7 are diagrams for describing equations obtained in accordance with an embodiment of the present invention;

FIG. 8 is a flowchart illustrating a method of controlling a display device according to an exemplary embodiment of the present invention.

9 is a flowchart for explaining a step-by-step method for obtaining an equation in a display device according to an embodiment of the present invention.

Claims (14)

In the display device, An illuminance sensing unit for sensing the illuminance of the surroundings of the display device; A memory unit storing an equation corresponding to each illumination level group divided into a predetermined number of groups; And And a control unit for extracting an equation corresponding to the illumination sensing state of the illumination sensing unit and setting a register value for adjusting the luminance level of the display device using the extracted equation, Wherein the equation is obtained based on a brightness level of a display device according to an illumination detection state in which a UGR (Unified Glare Rating) value is less than a specific level. The method according to claim 1, Wherein the memory unit divides the entire illumination sensing state into a predetermined number of groups and stores an equation corresponding to each group divided into the predetermined number. 3. The method of claim 2, Wherein the equation is for setting a register value according to a display device luminance level corresponding to an average luminance level of the input image data within a range of a maximum value and a minimum value of a display device luminance level in the same group Device. The method of claim 3, And the register values corresponding to the average luminance level and the display device luminance level are in inverse proportion to each other. The method of claim 3, The above equation is a linear equation consisting of an independent variable for the average luminance level, a and b of the independent variable, Wherein the solution (dependent variable) obtained through the linear equation is a register value corresponding to a display device luminance level to be applied. 6. The method of claim 5, The coefficient of the independent variable and the constant b Based on the first coordinate information made up of the register value and the minimum average brightness level value corresponding to the maximum average brightness level belonging to the same group and the second coordinate information made up of the register value and the maximum average brightness level value corresponding to the minimum average brightness level Wherein the display device is a display device. 6. The method of claim 5, Further comprising: a detection unit for detecting an average luminance level of a video signal input from the outside, Wherein the controller calculates a register value corresponding to a display device luminance level to be applied by substituting the detected average luminance level into the primary equation. A method of controlling a display device, Obtaining an equation having an average brightness level and a register value for each illumination sensing state as variables so that the UGR value is less than a specific level; Sensing ambient illumination of the display device; And And setting a register value according to an average luminance level of the input image data by applying an equation according to the sensed ambient illuminance. 9. The method of claim 8, Wherein the register value is backlight brightness information for causing the brightness level of the display device to be a specific level. 9. The method of claim 8, The step of obtaining the equation Obtaining a display device luminance level according to an illumination level at which the UGR value is less than a specific level; Designating illumination levels belonging to a certain range as a group; And obtaining an equation corresponding to the designated group. 11. The method of claim 10, The step of obtaining an equation corresponding to each group Confirming a maximum display device luminance level and a minimum display device luminance level at a display device luminance level set for each group; Determining a maximum average luminance level and a minimum average luminance level of input image data to which different register values are to be applied; Obtaining first coordinate information including a register value corresponding to the identified maximum display device luminance level and a minimum average luminance level and second coordinate information including a register value corresponding to the minimum display device luminance level and a minimum average luminance level Wow, And obtaining a linear equation corresponding to the first coordinate information and the second coordinate information using the obtained first coordinate information and second coordinate information. In the display device, A display panel for displaying an image input from the outside; A backlight for supplying light to the front of the display panel; A backlight driver for supplying driving power to the backlight; A sensor unit for detecting the ambient brightness of the display device; An average luminance level detector for detecting an average luminance level of each frame of an input video signal; A memory unit for storing a backlight brightness value according to a degree of surrounding brightness; And And a controller for adjusting the brightness of the backlight based on the amount of light detected through the sensor and the detected average brightness level, and adjusting a brightness of the backlight by determining a register value according to the detected average brightness level . 13. The method of claim 12, Wherein the detected ambient brightness level is grouped into a plurality of predetermined intervals, and the backlight adjustment value according to the degree of ambient brightness stored in the memory is a register value of an average luminance level according to each of the surrounding brightness groups. A control method of a display device for displaying a video signal inputted from outside, Detecting a light amount according to ambient brightness of the display device by a sensor unit; Receiving a video signal to be displayed on the display device; Detecting an average luminance level of the received video signal; Adjusting the brightness of the backlight based on the detected amount of light and the detected average brightness level, and adjusting the brightness of the backlight by determining a register value according to the detected average brightness level, Of the display device.

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