JP6130874B2 - Mobile terminal and mobile terminal control method - Google Patents

Description

  The present disclosure relates to a mobile terminal and a control method of the mobile terminal.

  2. Description of the Related Art Conventionally, portable terminals including a camera and a liquid crystal display (hereinafter also referred to as “LCD”) are known. In such a portable terminal, for example, as disclosed in Patent Document 1, the amount of external light (sunlight, artificial illumination light, etc.) around the LCD is detected at the time of photographing with a camera, and the amount of external light reaches a predetermined value. Some of them have a function (so-called auto backlight function) that makes it easy to visually recognize an image on the LCD by increasing the amount of light of the backlight of the LCD.

JP 2007-324888 A

  The portable terminal described above makes it easy to visually recognize an image on the LCD by increasing the amount of light of the backlight. However, since the amount of light from the backlight is limited, the visibility of the LCD can be improved even if the amount of light from the backlight is increased to the limit in an environment where the outside light is very strong (for example, outdoors under sunlight). There is concern that it cannot be secured sufficiently.

  Therefore, an object of the present disclosure is to sufficiently ensure the visibility of the display unit outdoors in a portable terminal including a display unit (for example, an LCD).

  A mobile terminal according to the present disclosure includes a display unit having a screen for displaying an image, an external light detection unit configured to be able to detect the amount of external light around the display unit and the ratio of a red component in the external light, And a control unit configured to be capable of adjusting the red luminance output from the display unit based on the ratio of the red component in the external light when the amount of the external light exceeds the threshold amount.

  A control method according to the present disclosure includes a display unit having a screen for displaying an image, and an external light configured to be able to detect a plurality of color components including the amount of external light around the screen and red in the external light. And a step of determining whether or not the amount of external light exceeds a threshold amount, and when it is determined that the amount of external light exceeds the threshold amount, Adjusting the red luminance output from the display unit based on the ratio of the red component in the light.

  According to the present disclosure, it is possible to sufficiently ensure the visibility of the display unit outdoors in a mobile terminal including the display unit.

It is a figure showing the structure of a portable terminal. It is a figure showing the external appearance from the front (surface) side of a portable terminal. It is a figure showing the external appearance from the back surface (back surface) side of a portable terminal. It is a figure for demonstrating the method in which a control part increases R brightness | luminance. It is a figure for demonstrating an example of the method in which a control part sets a red gamma value. It is a flowchart which shows the process sequence of a control part.

Hereinafter, embodiments will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration of a mobile terminal 1 according to the present embodiment. FIG. 2 is a diagram illustrating an appearance from the front (front surface) side of the mobile terminal 1 of FIG. FIG. 3 is a diagram illustrating an appearance of the mobile terminal 1 of FIG. 1 from the back (back) side.

  The portable terminal 1 will be described with reference to FIGS. 1, 2, and 3. The mobile terminal 1 includes an antenna 22, a wireless communication unit 21, a proximity sensor 6, a front camera 8, a rear camera 18, a receiver 7, a microphone 12, a button group 9, a touch screen 14, and a storage unit. 23, an external light sensor 20, an inclination sensor 30, and a control unit 100. The touch screen 14 includes a display unit 10 and a touch panel 13.

  The receiver 7 outputs the other party's voice or music data voice output from the control unit 100. The receiver 7 is composed of, for example, an electromagnetic speaker. Or the receiver 7 may be comprised from a piezoelectric vibration element, and may convey an audio | voice to a user by vibrating the surface panel.

  The microphone 12 receives the other party's voice and surrounding voices, and outputs them to the controller 100. The proximity sensor 6 detects the presence of a nearby object without contact. For example, the proximity sensor 6 detects that the display unit 10 has been brought close to the face. The rear camera 18 and the front camera 8 photograph a subject.

  The button group 9 functions as an operation receiving unit that receives user instruction operations for various processes. Examples of the operation receiving unit include a button (hardware key) realized as a physical mechanism, such as the button group 9, and a key (soft key) reproduced in software using the touch panel 13. .

  The radio communication unit 21 communicates with the radio base station through the antenna 22. The wireless communication unit 21 includes an A / D converter, a D / A converter, a modulation unit, a demodulation unit, a frequency converter, an amplification unit, and the like.

  The display unit 10 includes a screen 11 (see FIG. 2) for displaying an image based on the image data output from the control unit 100. The display unit 10 is a color liquid crystal display. That is, the display unit 10 has three colors (red (R), green (G), blue (B)) or four colors (red (R), green (G), blue (B), white (W)). It includes a filter layer in which filters of respective colors that transmit light are regularly arranged, a backlight that emits white light, and a liquid crystal layer that is disposed between the backlight and the filter layer. The liquid crystal layer is configured such that the amount of light transmitted from the backlight toward the filter of each color can be adjusted separately for each color.

  The brightness of the screen 11 is adjusted by changing the light amount of the backlight. The color tone of the screen 11 is adjusted by changing the combination of the red, green, and blue (or red, green, blue, and white) luminances that the screen 11 outputs. The brightness of each color (the amount of light transmitted through the filter of each color) can be adjusted separately by controlling the state of the liquid crystal molecules in the liquid crystal layer.

  Although display unit 10 according to the present embodiment is an LCD having a backlight, display unit 10 may be a display without a backlight, such as an organic EL (Electro-Luminescence) display.

  The touch panel 13 functions as an input receiving unit that receives input from the user. The touch panel 13 detects contact or proximity of an object (such as a user's finger or pen) according to a capacitance method, but the touch panel is not limited to this, for example, according to a method such as an infrared method or an electromagnetic induction method. User input may be detected. In addition to the touch panel, the input receiving unit may be anything that receives input without contact, for example, a proximity sensor. In addition, the input receiving unit may be a hardware key or the like.

  The external light sensor 20 includes an amount of external light (hereinafter also referred to as “peripheral illuminance”) irradiated around the display unit 10 and a ratio of a red component contained in the external light (hereinafter also referred to as “peripheral R ratio”). Is configured to be detectable. In the present embodiment, the ambient illuminance and the ambient R rate are detected by one external light sensor 20, but the ambient illuminance and the ambient R rate may be detected by separate sensors.

  The tilt sensor 30 is configured to be able to detect the tilt angle of the screen 11 of the display unit 10 with respect to the horizontal plane (hereinafter also referred to as “screen tilt”). The tilt sensor 30 can be realized by an acceleration sensor or a gyro sensor.

  The storage unit 23 is image data to be displayed on the screen 11 of the display unit 10, audio data to be output to the receiver 7, and whether or not the user has selected “Enable (On)” for the auto backlight function. Various information, such as data indicating whether or not, is stored.

  As shown in FIG. 2, the receiver 7, the front camera 8, and the proximity sensor 6 are disposed on the upper part of the front surface of the housing 2 of the mobile terminal 1. The display unit 10 and the touch panel 13 are arranged in the center of the front surface of the housing 2 of the mobile terminal 1. A touch panel 13 is disposed on the display unit 10. Note that the display unit 10 and the touch panel 13 may be disposed at a position shifted from the center of the front surface of the housing 2 of the mobile terminal 1. The microphone 12 is disposed in the lower part of the front surface of the housing 2 of the mobile terminal 1.

  The buttons 9 </ b> D, 9 </ b> E, and 9 </ b> F are disposed on the lower part of the front surface of the housing 2 of the mobile terminal 1. The button 9 </ b> A is disposed on the upper side surface of the housing 2 of the mobile terminal 1. The buttons 9 </ b> B and 9 </ b> C are disposed on the side of the side surface of the housing 2 of the mobile terminal 1.

  The button 9D is a back button. The button 9E is a home button. The button 9F is a menu button. The button 9A is a power on / off button. The button 9B is a volume up button. The button 9C is a volume down button.

  As shown in FIG. 3, the rear camera 18 is arranged on the upper part of the back surface of the housing 2 of the mobile terminal 1.

  The control unit 100 controls the entire mobile terminal 1. When the user has selected to “enable (turn on)” the auto backlight function, the control unit 100 automatically sets the backlight amount of the display unit 10 according to the ambient illuminance detected by the external light sensor 20. adjust. Thereby, the brightness of the entire image displayed on the screen 11 is automatically adjusted according to the ambient illuminance.

The control unit 100 can adjust the gamma characteristic (gamma value) of the display unit 10. The gamma characteristic is a characteristic indicating the relationship between input and output of the display. The gamma characteristics are: “X” for the color gradation (number of steps of color intensity that can be expressed) input to the display, “Y” for the luminance of the color output to the display, and “γ” for the gamma value. Then, it is expressed by an expression “Y = X ^γ ”.

  In the present embodiment, the initial value of the gamma value of each color is set to “2.2”. The control unit 100 can change the gamma value of each color separately. Thereby, the brightness | luminance of each color is adjusted separately and the color tone of the whole image displayed on the screen 11 is changed. For example, when the red gamma value (hereinafter also referred to as “R gamma value”) is changed, the overall red luminance of the screen 11 is changed, so that the red characteristic of the entire image displayed on the screen 11 is changed.

  Brightness of the image displayed on the screen 11 when the mobile terminal 1 having the above configuration is used under outdoor sunlight when the mobile terminal 1 is used indoors and when the mobile terminal 1 is used indoors and at night. Therefore, the visibility of the image displayed on the screen 11 is lowered. In particular, it has been found that when sunlight is irradiated, the red component of the visible light component output from the screen 11 is attenuated more than the other color components. That is, under sunlight, the red visibility is more likely to be lower than the visibility of other colors.

  As a countermeasure, it is conceivable to increase the brightness of the screen 11 by increasing the amount of backlight light by the above-described auto backlight function. However, there is a limit to the amount of backlight, so in environments with extremely high ambient illumination (for example, outdoors under sunlight), even if the amount of backlight is increased to the upper limit, the visibility of the image is reduced. There is concern that it cannot be secured sufficiently. Further, if the state in which the amount of backlight light is increased continues, there may be a problem that the surface temperature of the portable terminal 1 is excessively increased or the power consumption is excessively increased.

  Therefore, when the ambient illuminance exceeds the threshold value E0, the control unit 100 according to the present embodiment determines that the mobile terminal 1 is used under outdoor sunlight, and the visibility is the lowest due to sunlight. The visibility of the image is improved by increasing the luminance of the red component (hereinafter referred to as “R luminance”). At this time, in consideration of the amount of sunlight received by the user reflected on the screen 11 (hereinafter referred to as “user received light amount”) changing depending on the screen tilt, the control unit 100 considers the screen tilt and increases the R luminance. Adjust.

  FIG. 4 is a diagram for explaining a method in which the control unit 100 increases the R luminance. In FIG. 4, the horizontal axis represents the red gradation (hereinafter referred to as “R gradation”) input to the display unit 10, and the vertical axis represents the R luminance output from the display unit 10. When the R gradation is the minimum value, it represents the darkest red (black), and when the R gradation is the maximum value, it represents the lightest red.

The red gamma characteristic of the display unit 10 is expressed by the equation “Y = X ^γ ” as described above, where R gradation is “X”, R luminance is “Y”, and R gamma value is “γ”. The When the R gamma value is set to the initial value “2.2”, a curve obtained by plotting the R luminance value with respect to the R gradation (hereinafter referred to as “R gamma curve”) is a curve indicated by a solid line in FIG. When the R gamma value is set to “2.1” which is smaller than the initial value 2.2, the R gamma curve is a curve indicated by a one-dot chain line having a larger R luminance than the solid line in the intermediate gradation region. When the R gamma value is set to “2.0”, which is smaller than 2.1, the R gamma curve is a curve indicated by a two-dot chain line having a larger R luminance than the one-dot chain line in the intermediate gradation region.

  Thus, in the intermediate gradation area, the smaller the R gamma value, the larger the R luminance. The control unit 100 increases the R luminance by changing the R gamma value to “2.1” smaller than the initial value “2.2” or “2.0” smaller than the initial value “2.2”.

  FIG. 5 is a diagram for explaining an example of a method in which the control unit 100 sets the R gamma value when the mobile terminal 1 is used under sunlight. In FIG. 5, “evening state” described in the “peripheral R rate” column indicates a state where the peripheral R rate exceeds the threshold value P0, and “non-evening state” indicates a state where the peripheral R rate is less than the threshold value P0. Represents. In FIG. 5, “tilt state” described in the “screen tilt” column represents a state where the screen tilt exceeds the threshold value A0, and “horizontal state” represents a state where the screen tilt is less than the threshold value A0. . In FIG. 5, the peripheral illuminance “small” represents a state in which the peripheral illuminance is equal to or higher than the threshold E0 and less than the threshold E1 (E0 <E1). This represents a state where E1 is greater than or equal to and less than threshold E2 (E1 <E2), and ambient illuminance “high” represents a state where ambient illuminance is greater than or equal to threshold E2.

  If the peripheral R ratio is large due to the influence of sunset or the like, the periphery of the screen 11 is also reddish as a whole, and the red visibility of the image displayed on the screen 11 is relatively lowered. Furthermore, it is assumed that the amount of received light by the user increases depending on the screen tilt, and the red visibility of the screen 11 further decreases.

  In view of this point, the control unit 100 determines whether or not the peripheral R rate exceeds the threshold value P0 and whether or not the screen inclination exceeds the threshold value A0. Then, the control unit 100 stratifies the peripheral state of the screen 11 into any one of the patterns A to D according to these determination results, and performs a process of changing the R gamma value according to the stratified pattern.

  In the “evening state” and the “tilt state”, the pattern A is stratified. In the pattern A, it is assumed that not only the red visibility is lowered due to the sunset, but also the user's received light amount is large and the image visibility is further lowered. Considering this point, in the case of the pattern A, the control unit 100 reduces the R gamma value from the initial value “2.2” to “2.0” when the ambient illuminance is “medium” and “large”. As a result, the R luminance is greatly increased.

  In the “evening state” and the “horizontal state”, the pattern B is stratified. In the pattern B, the visibility of red color is reduced by sunset, but it is assumed that the amount of received light by the user is less than that of the pattern A. In consideration of this point, in the case of the pattern B, the control unit 100 reduces the increase amount of the R luminance when the ambient illuminance is “medium” as compared with the pattern A. That is, the R gamma value when the ambient illuminance is “medium” is set to “2.1” instead of “2.2”.

  In the “non-evening state” and the “tilt state”, the pattern C is classified. In the pattern C, the red visibility is not lowered due to the sunset, but it is assumed that the visibility of the image is lowered because the amount of light received by the user is large. Considering this point, in the case of the pattern C, the control unit 100 increases the R luminance in a stepwise manner according to the ambient illuminance. That is, when the ambient illuminance is “medium”, the R gamma value is changed from the initial value “2.2” to “2.1” to increase the R luminance by one step, and when the ambient illuminance is “high”, the R gamma value is increased. The initial value “2.2” is changed to “2.0” and the R luminance is increased by two steps.

  In the “non-evening state” and the “horizontal state”, the pattern D is stratified. In the pattern D, it is assumed that the red visibility is not deteriorated due to the sunset, and the user received light amount is further reduced than the pattern C. In consideration of this point, in the case of the pattern D, the control unit 100 reduces the increase amount of the R luminance when the ambient illuminance is “high” compared to the pattern C. That is, the R gamma value when the ambient illuminance is “high” is set to “2.1” instead of “2.0”.

  In any of the patterns A to D, when the ambient illuminance is “low”, it is considered that the influence of sunlight is small and the visibility of the image does not decrease so much, so the R gamma value is the initial value “2. 2 ".

  As described above, the control unit 100 stratifies the peripheral state of the screen 11 into the patterns A to D according to the peripheral R rate and the screen inclination, and increases the R luminance of the screen 11 according to the stratified pattern. Thereby, although the color tone of the screen 11 becomes more reddish than the color tone originally intended to be displayed, the visibility of the screen 11 outdoors can be dramatically improved.

  FIG. 6 is a flowchart illustrating a processing procedure in which the control unit 100 sets the R gamma value. This flowchart is repeatedly executed at a predetermined cycle when the auto backlight function is “valid (on)”. The reason why the auto backlight function is “valid (on)” is to ensure that the user is allowed to automatically change the state of the screen 11.

  In step (hereinafter, step is abbreviated as “S”) 10, control unit 100 determines whether or not the ambient illuminance exceeds threshold value E0. S10 is a process for determining whether or not the mobile terminal 1 is used under outdoor sunlight.

  When ambient illuminance exceeds threshold value E0 (YES in S10), control unit 100 sets the R gamma value by the outdoor processing shown in S20 (S21 to S27).

  Specifically, in S21, control unit 100 determines whether or not the peripheral R rate exceeds threshold value P0. S21 is a process for determining whether the state is the “evening state” or the “non-evening state” shown in FIG.

  When the peripheral R rate exceeds threshold value P0 (YES in S21), that is, in the “evening state”, control unit 100 determines whether or not the screen inclination exceeds threshold value A0 in S22. Determine whether. S22 is a process for determining whether the state is the “inclined state” or the “horizontal state” shown in FIG.

  If the screen inclination exceeds threshold value A0 (YES in S22), control unit 100 determines in step S23 the R gamma value corresponding to the ambient illuminance by the process shown in “Pattern A” in FIG. Set. Specifically, the control unit 100 sets the R gamma value to the initial value “2.2” when the ambient illuminance is “small”, and sets the R gamma value to “2” when the ambient illuminance is “medium” or “large”. 2.0 ".

  When the screen inclination is less than threshold value A0 (NO in S22), control unit 100 obtains an R gamma value corresponding to the ambient illuminance by the process shown in “Pattern B” in FIG. 5 described above in S24. Set. Specifically, the control unit 100 sets the R gamma value to the initial value “2.2” when the ambient illuminance is “small”, and sets the R gamma value to “2.1” when the ambient illuminance is “medium”. When the ambient illuminance is “high”, the R gamma value is set to “2.0”.

  On the other hand, when peripheral R rate is less than threshold value P0 (NO in S21), that is, in the “non-evening state”, control unit 100 causes screen inclination to exceed threshold value A0 in S25. It is determined whether or not. S25 is a process for determining whether the state is the “inclined state” or the “horizontal state” shown in FIG.

  When the screen inclination exceeds threshold value A0 (YES in S25), control unit 100 determines in step S26 the R gamma value corresponding to the ambient illuminance by the process shown in “Pattern C” in FIG. Set. Specifically, the control unit 100 sets the R gamma value to the initial value “2.2” when the ambient illuminance is “small”, and sets the R gamma value to “2.1” when the ambient illuminance is “medium”. When the ambient illuminance is “high”, the R gamma value is set to “2.0”.

  If the screen inclination is less than threshold A0 (NO in S25), control unit 100 obtains an R gamma value corresponding to the ambient illuminance in S27 by the process shown in “Pattern D” in FIG. Set. Specifically, the control unit 100 sets the R gamma value to the initial value “2.2” when the ambient illuminance is “small”, and sets the R gamma value to “2” when the ambient illuminance is “medium” or “large”. 2.1 ”.

  If ambient illuminance is less than threshold value E0 (NO in S10), control unit 100 sets the R gamma value by indoor processing in S30. In indoor processing, since the influence of external light is small, for example, the R gamma value is fixed to the initial value “2.2”.

  As described above, the mobile terminal 1 according to the present embodiment includes the display unit 10 having the screen 11 for displaying an image, the amount of external light (peripheral illuminance) around the display unit 10, and red in external light. An external light sensor 20 configured to be able to detect a component ratio (peripheral R rate) and a control unit 100 are provided. When the ambient illuminance exceeds the threshold value E0, the control unit 100 determines that the mobile terminal 1 is being used in outdoor sunlight, and the luminance (R) of the red component that is most likely to deteriorate in visibility due to sunlight. Brightness). Thereby, the visibility of the display unit 10 outdoors can be sufficiently ensured.

  In particular, in this embodiment, since the R luminance is increased by adjusting the R gamma value (controlling the state of the liquid crystal molecules in the liquid crystal layer), it is sufficient that the amount of backlight light is not increased so much. Visibility can be secured. Therefore, since the increase amount of the backlight light quantity can be suppressed, an increase in the surface temperature of the mobile terminal 1 and an increase in power consumption can be suppressed.

<Modification>
The above-described embodiment can be modified as follows, for example.

  (1) In the above-described embodiment, the R gamma value is adjusted when the auto backlight function is enabled (on), but the R gamma value is adjusted when the auto backlight function is disabled (off). Adjustments may be made.

  (2) In the above-described embodiment, the R gamma value is adjusted according to the three parameters “peripheral R rate”, “screen tilt”, and “peripheral illumination” as shown in FIG. It is not necessary to use all two parameters. For example, the R gamma value may be adjusted using at least one of “peripheral R rate” and “screen tilt” as a parameter.

  For example, when “peripheral R rate” is used as a parameter, the R gamma value when the peripheral R rate exceeds the threshold value P0 (in the “evening state”), the peripheral R rate is less than the threshold value P0. The R luminance may be increased by making it smaller than the R gamma value at a certain time (in the “non-evening state”). When “screen tilt” is used as a parameter, the R gamma value when the screen tilt exceeds the threshold value A0 (in the “tilt state”) and the screen tilt is less than the threshold value A0 ( The R luminance may be increased by making it smaller than the R gamma value in the “horizontal state”.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 mobile terminal, 2 housing, 6 proximity sensor, 7 receiver, 8 front camera, 9 button group, 9A, 9B, 9C, 9D, 9E, 9F button, 10 display unit, 11 screen, 12 microphone, 18 rear camera, 20 external light sensor, 21 wireless communication unit, 22 antenna, 23 storage unit, 30 tilt sensor, 100 control unit.

Claims (6)

A display unit having a screen for displaying an image;
An external light detection unit configured to be able to detect the amount of external light around the display unit and the ratio of the red component in the external light;
A control unit configured to adjust the red luminance output from the display unit according to a ratio of a red component in the external light when the amount of the external light exceeds a threshold amount ;
When the ratio of the red component in the external light exceeds the threshold ratio, the control unit outputs the red luminance output by the display unit more than when the ratio of the red component in the external light is less than the threshold ratio. A mobile terminal with a large value . The mobile terminal further includes an angle detection unit capable of detecting an inclination angle of the screen of the display unit with respect to a horizontal plane,
When the amount of the external light exceeds the threshold amount, the control unit adjusts a red luminance output from the display unit based on a tilt angle of the screen in addition to a ratio of a red component in the external light. The mobile terminal according to claim 1 . When the ratio of the red component in the external light exceeds the threshold ratio and the tilt angle of the screen exceeds the threshold angle, the control unit determines that the ratio of the red component in the external light is The mobile terminal according to claim 2 , wherein the red luminance output by the display unit is set to a larger value than when the threshold ratio is exceeded and the screen tilt angle is less than the threshold angle. When the ratio of the red component in the external light is less than the threshold ratio and the tilt angle of the screen exceeds the threshold angle, the control unit determines that the ratio of the red component in the external light is 3. The mobile terminal according to claim 2 , wherein the red luminance output from the display unit is set to a larger value than the case where the ratio is less than the threshold ratio and the tilt angle of the screen is less than the threshold angle. When the ratio of the red component in the external light exceeds the threshold ratio and the tilt angle of the screen exceeds the threshold angle, the control unit determines that the ratio of the red component in the external light is When the threshold ratio is exceeded and the tilt angle of the screen is less than the threshold angle, the ratio of the red component in the external light is less than the threshold ratio, and the tilt angle of the screen is If the angle exceeds the corner, the red luminance output by the display unit is greater than when the proportion of the red component in the external light is less than the threshold proportion and the screen tilt angle is less than the threshold angle. The mobile terminal according to claim 2 , wherein a large value is set. A display unit having a screen for displaying an image; and an external light detection unit configured to be capable of detecting components of a plurality of colors including the amount of external light around the screen and red in the external light A method for controlling a mobile terminal,
Determining whether the amount of external light exceeds a threshold amount;
If the amount of the external light is determined to exceed the threshold amount, seen including a step of the display unit adjusts the red luminance output based on the ratio of the red component in the outer light,
The step of adjusting the red luminance output by the display unit includes a case where the ratio of the red component in the external light exceeds the threshold ratio, and the case where the ratio of the red component in the external light is less than the threshold ratio. And a method of controlling the portable terminal, including the step of increasing the red luminance output from the display unit .

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