JP2006221083A - Light emission controlling device and light emission control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emission controlling device and a light emission control method for decreasing consumption of electric power without decreasing visibility of a displayed image. <P>SOLUTION: The invention provides a digital camera 10 having an LCD (liquid crystal display) 38 to display an image and a plurality of LEDs (fabricated in a backlight unit 38A) individually emitting light to illuminate the respective regions different from one another in the display region of the LCD 38, wherein in order to control the light emission state of the LEDs, the plurality of LEDs are configured in such a manner that at least one of the plurality of LEDs is selectively controlled to emit light, and the number of LEDs emitting light is controlled by a CPU 40 through an LCD interface 36 according to preliminarily determined conditions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emission control device and a light emission control method, and in particular, display means for displaying an image, and a plurality of light emission means for illuminating different areas in the display area of the display means by each emitting light. The present invention relates to a light emission control device and a light emission control method for controlling the light emission state of the light emitting means of a display device having a display.

  In recent years, various types of displays such as CRT displays, liquid crystal displays, organic EL displays, plasma displays, and the like have been used as display devices for displaying images.

  On the other hand, some of these display devices use a display unit such as a liquid crystal panel of a liquid crystal display, in which the display area itself is dark and the displayed image has low visibility as it is.

  In such a display device, in order to improve the visibility of a display image, light from the outside is collected to irradiate the display area, or a backlight is incorporated to irradiate the display area with light from the backlight. Things to do are widespread.

  Among these, in a display device with a built-in backlight, light is emitted from a light emitting element such as a light emitting tube or LED (light emitting diode), and the emitted light is irradiated to the display region via a diffusion plate, The entire display area is illuminated.

  By the way, in a portable information device such as a digital camera, a mobile phone, and a PDA (Personal Digital Assistant, personal digital assistant) provided with a display device having a light emitting element for illumination with respect to such a display area, it is assumed that it is driven by a battery. Therefore, it is desirable to reduce power consumption as much as possible.

For this reason, conventionally, there has been a technique for extracting a feature amount of data in an arbitrary image region of image data to be displayed on a liquid crystal display and changing the luminance of the backlight based on the feature amount (for example, patents). Reference 1).
JP 2004-198512 A

  However, in the technology for changing the brightness of the backlight, when the brightness of the backlight is lowered, the display area of the liquid crystal display becomes dark overall, so that the visibility of the display image is lowered. There was a problem.

  That is, the backlight circuit of the liquid crystal display has a plurality of light emitting elements (three light emitting diodes LED1 to LED3 in FIG. 12) connected in series as shown in FIG. 12 as an example in order to prevent uneven brightness in the display area. In general, a constant current circuit is configured.

  When the backlight emits light with normal luminance, the switch SW is turned on to connect the resistors R1 and R2 in parallel to reduce the resistance value and cause each light emitting element to emit light with normal luminance. When the light is emitted at a lower luminance than the normal luminance, the switch SW is turned off to increase the resistance value of the resistor so that each light emitting element emits the light at a luminance lower than the normal luminance.

  For this reason, when the brightness of the backlight is lowered in the technique for changing the brightness of the backlight, the display area of the liquid crystal display becomes dark overall.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a light emission control device and a light emission control method capable of reducing power consumption without reducing the visibility of a display image. .

  To achieve the above object, the light emission control device according to claim 1 includes a display means for displaying an image and a plurality of light emission means for illuminating different areas in the display area of the display means by emitting light respectively. And a light emission control device for controlling a light emission state of the light emitting means of the display device, wherein the plurality of light emitting means can selectively emit at least one of the plurality of light emitting means. The light emission control means is configured to control the number of light emission of the plurality of light emission means in accordance with a predetermined condition.

  According to the light emission control device of claim 1, the plurality of light emitting units that illuminate different areas in the display area of the display unit by emitting light selectively emit at least one of the plurality of light emitting units. It is comprised so that it can be made. The display means includes various displays such as a CRT display, a liquid crystal display, an organic EL display, and a plasma display. The light emitting means includes various light emitting elements such as an arc tube and an LED.

  In the present invention, the light emission number of the plurality of light emitting means is controlled by the light emission control means in accordance with a predetermined condition.

  Thus, according to the light emission control device of the first aspect, the display means for displaying an image, and the plurality of light emission means for illuminating different areas in the display area of the display means by each emitting light. When controlling the light emission state of the light emitting means of the display device having a plurality of light emitting means, the plurality of light emitting means are configured to selectively emit at least one of the plurality of light emitting means, and are determined in advance. Since the number of light emission of the plurality of light emitting means is controlled according to the specified conditions, if the number of light emission is less than the total number of light emitting means, the light emission that emits light in the display area of the display means Since the brightness of the area illuminated by the means is not reduced, the power consumption can be reduced without reducing the visibility of the display image in the area.

  In the present invention, the display means may be a liquid crystal display, and the plurality of light emitting means may be backlights that illuminate the display area of the liquid crystal display. Thereby, it is possible to reduce the power consumption of the backlight that illuminates the display area of the liquid crystal display without reducing the visibility of the display image.

  Further, according to the present invention, as in the third aspect of the present invention, the predetermined condition may be whether or not the power consumption is desired to be reduced. Thereby, when it is desired to reduce the power consumption, the power consumption can be reduced. The state in which the power consumption is desired to be reduced includes a state in which execution of the low power consumption mode is instructed, a state in which the remaining capacity of the battery is less than a predetermined amount when power is supplied by the battery, etc. Is included.

  Further, according to the present invention, when only a part of the plurality of light emitting units emits light by the light emission control unit, the display image by the display unit is displayed by the partial light emitting unit. You may further provide the display control means which controls the said display means to display within an illumination range. As a result, the display image can be reliably recognized.

  In particular, the display control means of the invention described in claim 4 reduces the display image and displays it within the illumination range as in the invention described in claim 5, or a part of the display image. The display means may be controlled to display only the region within the illumination range. Thus, when the display image is reduced and displayed, the entire display image can be visually recognized, and when only a partial area of the display image is displayed, the display image can be displayed at the same magnification or magnification. Therefore, the visibility with respect to the partial region can be further improved.

  Further, the light emission control means of the invention described in claim 3 is the case where the power consumption is reduced as the predetermined condition as in the invention described in claim 6, and the When a predetermined display image by the display means is displayed only in a partial area of the display area of the display means, control may be performed so that only the light emitting means that illuminates the partial area emits light. Thereby, the predetermined display image can be surely visually recognized. The predetermined display image includes various menu images, thumbnail images, and the like.

  On the other hand, in order to achieve the above object, the light emission control method according to claim 7 includes a display means for displaying an image, and a plurality of illumination areas that illuminate different areas in the display area of the display means by emitting light respectively. A light emission control method for controlling a light emission state of the light emission means of a display device having a light emission means, wherein the plurality of light emission means can selectively cause at least one of the plurality of light emission means to emit light. In addition, the number of light emission of the plurality of light emitting means is controlled according to a predetermined condition.

  Therefore, according to the light emission control method according to the seventh aspect, since it operates in the same manner as the invention according to the first aspect, it is possible to consume the display image without reducing the visibility as in the first aspect. Electric power can be reduced.

  In the seventh aspect of the invention, as in the eighth aspect of the invention, the display means may be a liquid crystal display, and the plurality of light emitting means may be backlights that illuminate the display area of the liquid crystal display. . Thereby, it is possible to reduce the power consumption of the backlight that illuminates the display area of the liquid crystal display without reducing the visibility of the display image.

  Further, in the invention described in claim 7 or claim 8, as in the invention described in claim 9, the predetermined condition may be whether or not the power consumption is desired to be reduced. . Thereby, when it is desired to reduce the power consumption, the power consumption can be reduced.

  Further, in the invention according to any one of claims 7 to 9, the display image by the display means when only a part of the plurality of light emitting means emits light as in the invention according to claim 10. The display means may be controlled so as to display within the illumination range of the part of the light emitting means. As a result, the display image can be reliably recognized.

  In particular, in the invention described in claim 10, as in the invention described in claim 11, the display image is reduced and displayed in the illumination range, or only a partial region of the display image is displayed in the illumination. The display means may be controlled to display within a range. Thus, when the display image is reduced and displayed, the entire display image can be visually recognized, and when only a partial area of the display image is displayed, the display image can be displayed at the same magnification or magnification. Therefore, the visibility with respect to the partial region can be further improved.

  According to a ninth aspect of the present invention, there is provided a case where, as in the case of the twelfth aspect of the present invention, the power consumption is reduced as the predetermined condition, and the predetermined display by the display means is performed. When an image is displayed only in a partial area of the display area of the display means, control may be performed so that only the light emitting means that illuminates the partial area emits light. Thereby, the predetermined display image can be surely visually recognized.

  According to the present invention, the light emission of the light emitting means of the display device comprising: display means for displaying an image; and a plurality of light emitting means for illuminating different areas in the display area of the display means by emitting light. In controlling the state, the plurality of light emitting units are configured to selectively emit at least one of the plurality of light emitting units, and the plurality of light emitting units according to a predetermined condition. Therefore, when the number of light emission is less than the total number of light emitting means, the luminance of the display area in the display means is reduced for the area illuminated by the light emitting means. Therefore, the power consumption can be reduced without reducing the visibility of the display image in the region.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, a case where the light emission control device and the light emission control method according to the present invention are applied to a digital camera having a liquid crystal display will be described.

[First Embodiment]
First, an external configuration of the digital camera 10 according to the present embodiment will be described with reference to FIG.

  In front of the digital camera 10, a lens 21 for forming a subject image, a strobe 44 that emits light to irradiate the subject when necessary, and a viewfinder used to determine the composition of the subject to be photographed. 20 is provided. Further, on the upper surface of the digital camera 10, a release switch (so-called shutter) 56A, a power switch 56B, and a mode changeover switch 56C that are pressed when performing shooting are provided.

  Note that the release switch 56A of the digital camera 10 according to the present embodiment is pressed down to an intermediate position (hereinafter referred to as “half-pressed state”) and to a final pressed position beyond the intermediate position. A two-stage pressing operation of a state (hereinafter referred to as a “fully pressed state”) can be detected.

  In the digital camera 10, the release switch 56A is pressed halfway to activate the AE (Automatic Exposure) function to set the exposure state (shutter speed, aperture state), and then AF (Auto Focus). , Automatic focusing) function is performed to control focusing, and then exposure (photographing) is performed when the button is fully pressed.

  The mode changeover switch 56C is rotated when setting to any one of a shooting mode that is a mode for shooting and a playback mode that is a mode for playing back a subject image on the LCD 38 described later.

  On the other hand, on the back surface of the digital camera 10, an eyepiece part of the finder 20 described above, a photographed subject image, a menu screen, and the like are displayed, and a backlight part 38A (not shown in FIG. 1, not shown in FIG. 1). A liquid crystal display (hereinafter, referred to as “LCD”) 38 having a cross-cursor switch 56D is provided. The cross-cursor switch 56D includes four arrow keys that indicate four moving directions of up, down, left, and right in the display area of the LCD 38. In the digital camera 10 according to the present embodiment, an LCD 38 having a display area with an aspect ratio of 16: 9 is applied.

  Furthermore, on the back of the digital camera 10, a menu switch that is pressed when displaying the menu screen on the LCD 38, a determination switch that is pressed when confirming the operation content up to that point, and the previous operation content are displayed. A cancel switch that is pressed when canceling, a strobe switch that is pressed when setting the light emission state of the strobe 44, and a macro shooting switch that is pressed when performing macro shooting are provided. .

  Next, with reference to FIG. 2, the main configuration of the electrical system of the digital camera 10 according to the present embodiment will be described.

  The digital camera 10 includes an optical unit 22 including the lens 21 described above, a charge coupled device (hereinafter referred to as “CCD”) 24 disposed behind the optical axis of the lens 21, and an input analog. And an analog signal processing unit 26 that performs various analog signal processing on the signal.

  The digital camera 10 also performs an analog / digital converter (hereinafter referred to as “ADC”) 28 that converts an input analog signal into digital data, and performs various digital signal processing on the input digital data. And a digital signal processing unit 30.

  The digital signal processing unit 30 has a built-in line buffer having a predetermined capacity, and also performs control to directly store the input digital data in a predetermined area of the memory 48 described later.

  The output terminal of the CCD 24 is connected to the input terminal of the analog signal processing unit 26, the output terminal of the analog signal processing unit 26 is connected to the input terminal of the ADC 28, and the output terminal of the ADC 28 is connected to the input terminal of the digital signal processing unit 30. . Accordingly, the analog signal indicating the subject image output from the CCD 24 is subjected to predetermined analog signal processing by the analog signal processing unit 26, converted into digital image data by the ADC 28, and then input to the digital signal processing unit 30.

  On the other hand, the digital camera 10 generates a signal for displaying a subject image, a menu screen or the like on the LCD 38 and supplies the signal to the LCD 38, and a CPU (Central Processing Unit) 40 that controls the operation of the entire digital camera 10. A memory 48 that temporarily stores digital image data obtained by photographing, and a memory interface 46 that controls access to the memory 48 are included. The LCD interface 36 also has a role of controlling the operation of the backlight unit 38A provided in the LCD 38.

  Further, the digital camera 10 includes an external memory interface 50 for enabling the portable memory card 52 to be accessed by the digital camera 10, a compression / decompression processing circuit 54 for performing compression processing and expansion processing on digital image data, and an LCD 38. The image displayed on the screen is reduced at a specified reduction ratio and displayed at the specified position, and the image of only the specified area is cut out from the image displayed on the LCD 38 and displayed at the specified position. And an image processing unit 58 that performs trimming display processing.

  In the digital camera 10 of the present embodiment, a flash memory is used as the memory 48, and a smart media (Smart Media (registered trademark)) is used as the memory card 52.

  The digital signal processing unit 30, the LCD interface 36, the CPU 40, the memory interface 46, the external memory interface 50, the compression / decompression processing circuit 54, and the image processing unit 58 are connected to each other via a system bus BUS. Therefore, the CPU 40 controls the operation of the digital signal processing unit 30, the compression / decompression processing circuit 54 and the image processing unit 58, displays various information via the LCD interface 36 on the LCD 38, and the backlight unit via the LCD interface 36. 38A can be controlled, and the memory 48 and the memory card 52 can be accessed via the memory interface 46 and the external memory interface 50, respectively.

  On the other hand, the digital camera 10 includes a timing generator 32 that mainly generates a timing signal for driving the CCD 24 and supplies the timing signal to the CCD 24, and the driving of the CCD 24 is controlled by the CPU 40 via the timing generator 32.

  Further, the digital camera 10 is provided with a motor drive unit 34, and driving of a focus adjustment motor, a zoom motor, and an aperture drive motor (not shown) provided in the optical unit 22 is also controlled by the CPU 40 via the motor drive unit 34. The

  In other words, the lens 21 according to the present embodiment has a plurality of lenses, is configured as a zoom lens that can change (magnify) the focal length, and includes a lens driving mechanism (not shown). The lens drive mechanism includes the focus adjustment motor, the zoom motor, and the aperture drive motor, and these motors are each driven by a drive signal supplied from the motor drive unit 34 under the control of the CPU 40.

  Further, various switches such as the release switch 56A, the power switch 56B, the mode switch 56C, the cross cursor switch 56D, and the menu switch (generally referred to as “operation unit 56” in the figure) are connected to the CPU 40. The CPU 40 can always grasp the operation state with respect to the operation unit 56.

  In addition, the digital camera 10 includes a charging unit 42 that is interposed between the strobe 44 and the CPU 40 and charges power for causing the strobe 44 to emit light under the control of the CPU 40. Further, the strobe 44 is also connected to the CPU 40, and the light emission of the strobe 44 is controlled by the CPU 40.

  Next, the configuration of the LCD 38 according to the present embodiment will be described with reference to FIG.

  As shown in the figure, the LCD 38 includes a liquid crystal panel 70 that displays an image based on image data, and a plurality of (here, three) LEDs 60A, 60B, and 60C included in the backlight unit 38A. Is provided.

  Here, each LED 60A to 60C is in the vicinity of one side of the display surface of the liquid crystal panel 70 (in the example shown in the figure, the lower side) so that the light emission direction during light emission is the display surface direction of the liquid crystal panel 70. Are arranged at predetermined intervals along the side.

  In addition, although illustration is abbreviate | omitted in the figure, between the liquid crystal panel 70 and each LED60A-60C, the light diffusing plate which diffuses the light inject | emitted from each LED60A-60C is provided.

  Next, with reference to FIG. 4, the configuration of the main part of the electrical system of the backlight unit 38A will be described.

  As shown in the figure, in the backlight unit 38A, the applied reference voltage is boosted to a predetermined voltage, and flows at the supply destination with reference to the feedback voltage Vfb from the supply destination of the boosted voltage. A booster circuit 62 configured as an IC (semiconductor integrated circuit) that performs feedback control so as to keep the current constant is provided.

  In the digital camera 10 according to the present embodiment, the reference voltage is applied to the booster circuit 62 from a built-in battery (not shown). In addition, a series circuit including three LEDs 60A to 60C is connected between an output terminal that outputs a boosted voltage by the booster circuit 62 and an input terminal that inputs a feedback voltage Vfb.

  Here, switches 64A and 64B each having one movable contact and two fixed contacts are interposed between LED 60A and LED 60B and between LED 60B and LED 60C.

  Specifically, the switch 64A has one fixed contact connected to the cathode of the LED 60B, the other fixed contact connected to the output terminal to which the boosted voltage of the booster circuit 62 is applied, and the movable contact connected to the anode of the LED 60A. Yes. The switch 64B has one fixed contact connected to the cathode of the LED 60C, the other fixed contact connected to the output terminal to which the boosted voltage of the booster circuit 62 is applied, and the movable contact connected to the anode of the LED 60B.

  The control terminals of the switches 64A and 64B are connected to the LCD interface 36, and the connection state of the switches 64A and 64B is controlled by the CPU 40 via the LCD interface 36.

  On the other hand, the cathode of the LED 60 </ b> A (input terminal for inputting the feedback voltage Vfb of the booster circuit 62) is grounded via the resistor 66.

  With the above configuration, in the backlight unit 38A according to the present embodiment, stable light emission of each LED 60A to 60C is controlled by the booster circuit 62, and each LED 60A to 60C is controlled by the CPU 40 via the LCD interface 36. It is comprised so that at least 1 of these can be light-emitted selectively.

  By the way, the digital camera 10 according to the present embodiment is equipped with a light emission control function for controlling the light emission state (number of light emission) of each LED 60A to 60C of the backlight unit 38A when the LCD 38 is used.

  Note that in the light emission control function according to the present embodiment, only some of the LEDs 60A to 60C may emit light, and in this case, the entire display image is reduced to the display area that is the target of illumination by the LEDs that emit light. A reduction mode, which is an operation mode to be displayed, can be set.

  Further, in the digital camera 10 according to the present embodiment, it is possible to set a power save mode (so-called low power consumption mode) that is an operation mode in which power consumption can be reduced as compared with normal operation. In the digital camera 10 according to the present embodiment, the reduction mode and the power save mode can be set on a menu screen displayed on the LCD 38 by pressing a menu switch.

  Next, an overall operation at the time of shooting of the digital camera 10 according to the present embodiment will be briefly described.

  First, the CCD 24 performs imaging through the optical unit 22 and sequentially outputs analog signals for R (red), G (green), and B (blue) indicating the subject image to the analog signal processing unit 26. The analog signal processing unit 26 performs analog signal processing such as correlated double sampling processing on the analog signal input from the CCD 24 and sequentially outputs the analog signal to the ADC 28.

  The ADC 28 converts the R, G, and B analog signals input from the analog signal processing unit 26 into 12-bit R, G, and B signals (digital image data) and sequentially outputs them to the digital signal processing unit 30. To do. The digital signal processing unit 30 accumulates digital image data sequentially input from the ADC 28 in a built-in line buffer and temporarily stores the digital image data directly in a predetermined area of the memory 48.

  The digital image data stored in a predetermined area of the memory 48 is read out by the digital signal processing unit 30 under the control of the CPU 40, and white balance adjustment is performed by applying a digital gain according to a predetermined physical quantity. Processing and sharpness processing are performed to generate 8-bit digital image data.

  The digital signal processing unit 30 performs YC signal processing on the generated 8-bit digital image data to generate a luminance signal Y and chroma signals Cr and Cb (hereinafter referred to as “YC signal”), and the YC signal. Are stored in an area different from the predetermined area of the memory 48.

  The LCD 38 is configured to display a moving image (through image) obtained by continuous imaging by the CCD 24 and can be used as a finder. When the LCD 38 is used as a finder, the LCD 38 is generated. The YC signals thus output are sequentially output to the LCD 38 via the LCD interface 36. As a result, a through image is displayed on the LCD 38.

  Here, at the timing when the release switch 56A is half pressed by the user, after the AE function is activated and the exposure state is set as described above, the AF function is activated and the focus control is performed, and then the fully pressed state is continued. The YC signal stored in the memory 48 at that time is compressed in a predetermined compression format (in this embodiment, JPEG format) by the compression / decompression processing circuit 54 and then the external memory interface 50 is And recorded as an electronic file in the memory card 52.

  Next, the operation of the digital camera 10 when executing the light emission control function will be described with reference to FIG. FIG. 5 is a flowchart showing a flow of processing of the light emission control processing program executed by the CPU 40 of the digital camera 10 every predetermined period (here, 1 second), and the program is stored in a predetermined area of the memory 48 in advance. It is remembered.

  First, in step 100 of the figure, it is determined whether or not the LCD 38 is being used. If an affirmative determination is made, the process proceeds to step 102 to determine whether or not the power save mode is set. If it is determined that the normal operation mode has been set, the routine proceeds to step 104.

  In step 104, the LCD interface 36 is controlled so that all of the LEDs 60A to 60C are lit, and then the main light emission control processing program is terminated.

  On the other hand, if the determination in step 102 is affirmative, the process proceeds to step 106, and the LCD interface 36 is controlled so that only some of the predetermined LEDs among the LEDs 60A to 60C are lit (emitted). Thereafter, the process proceeds to step 108.

  In step 108, it is determined whether or not the reduction mode is set. If the determination is affirmative, the process proceeds to step 110 to control the image processing unit 58 so as to execute the reduction display process. On the other hand, when the light emission control processing program is finished, when the determination is negative, the light emission control processing program is finished without executing the processing of step 110. In step 110, the image processing unit 58 sets a reduction ratio at which the entire display image can be displayed in the illumination area of the LED controlled to be lit up in step 106 as the reduction ratio of the display image. The position in the illumination area is set as the display position.

  On the other hand, if a negative determination is made in step 100, the process proceeds to step 112, and the LCD interface 36 is controlled so that all the LEDs 60A to 60C are turned off, and then the light emission control processing program is terminated.

  FIG. 6A shows an example of a display state on the LCD 38 when the LCD 38 is in use, the power save mode is set, and the reduction mode is not set. In the figure, only the LED 60A that illuminates the area of approximately one third of the left end side of the display area of the liquid crystal panel 70 of the LCD 38 is shown.

  As shown in the figure, in this case, since only the LED 60A is turned on, the power consumption required for turning on the LED can be reduced to about one-third compared to that during normal operation. However, in this case, it is possible to visually recognize the image portion displayed in the region illuminated by the LED 60A, but it is difficult to visually recognize the image portion displayed in the other region.

  On the other hand, FIG. 6B shows an example of a display state by the LCD 38 when the LCD 38 is in use, the power save mode is set, and the reduction mode is set. Note that FIG. 5 also shows a case where only the LED 60 </ b> A responsible for illuminating the one-third region on the left end side of the display region in the liquid crystal panel 70 of the LCD 38 is made to emit light.

  As shown in the figure, in this case, since only the LED 60A is lit, the power consumption required to turn on the LED can be reduced to about one-third compared to that during normal operation. It is the same as the case where it is not done. Furthermore, in this case, the entire display image is displayed in a reduced size with respect to the area illuminated by the LED 60A, so that the entire display image can be visually recognized.

  As described above in detail, in the present embodiment, a plurality of display means (here, LCD 38) for displaying an image and a plurality of areas that illuminate different areas in the display area of the display means by emitting light. In controlling a light emission state of the light emitting means of a display device having light emitting means (here, LEDs 60A to 60C), the plurality of light emitting means selectively cause at least one of the plurality of light emitting means to emit light. Since the number of light emission of the plurality of light emitting means is controlled according to a predetermined condition, when the light emission number is less than the total number of light emitting means, the display means Among the display areas in the display area, the brightness of the area illuminated by the light emitting means that emits light is not reduced. It is possible to reduce power consumption without lowering.

  In this embodiment, since the display means is a liquid crystal display, and the plurality of light emitting means are backlights that illuminate the display area of the liquid crystal display, the backlight that illuminates the display area of the liquid crystal display is displayed. The power consumption can be reduced without reducing the visibility of the image.

  In the present embodiment, the predetermined condition is whether or not the power consumption is reduced (here, the power save mode is set). When it is desired to reduce the power, the power consumption can be reduced.

  Further, in the present embodiment, when only a part of the plurality of light emitting units emits light, the display unit is controlled so that a display image by the display unit is displayed within an illumination range of the some light emitting units. Therefore, the display image can be surely visually recognized.

  In particular, in the present embodiment, since the display means is controlled to reduce the display image and display it within the illumination range, the entire display image can be visually recognized.

[Second Embodiment]
In the second embodiment, when only a part of the LEDs 60 </ b> A to 60 </ b> C emits light, an example in which only a partial region of the display image by the LCD 38 is displayed within the illumination range of the part of the LEDs will be described. To do. Note that the configuration of the digital camera 10 according to the second embodiment is the same as that of the digital camera 10 according to the first embodiment (see FIGS. 1 to 4). Omitted.

  However, in the digital camera 10 according to the second embodiment, when only a part of the LEDs 60A to 60C is caused to emit light instead of the reduction mode, a display image is displayed in a display area that is an illumination target of the emitted LED. The trimming mode for cutting out and displaying only a part of the area is set on the menu screen displayed on the LCD 38 by pressing the menu switch.

  Hereinafter, the operation of the digital camera 10 according to the second embodiment when the light emission control function is executed will be described with reference to FIG. FIG. 7 is a flowchart showing a processing flow of the light emission control processing program according to the second embodiment executed by the CPU 40 of the digital camera 10 every predetermined period (here, 1 second). The program is stored in a predetermined area of the memory 48 in advance. Further, steps in FIG. 5 that perform the same processing as in FIG. 5 are assigned the same step numbers as in FIG.

  In step 108B in the figure, it is determined whether or not the trimming mode is set. If the determination is affirmative, the process proceeds to step 110B and trimming processing is performed as shown below.

  First, as shown in FIG. 8A as an example, the LCD interface 36 is controlled so that all of the LEDs 60A to 60C are lit, and the trimming frame 80 having a predetermined size and the arrow keys of the cross cursor switch 56D are used. The LCD interface 36 is controlled so as to display an arrow and an end button corresponding to.

  In response to this, the user of the digital camera 10 designates the end button after moving the trimming frame 80 by operating the arrow key of the cross cursor switch 56D so as to surround a desired partial region in the display image.

  Therefore, the CPU 40 sets information indicating the area surrounded by the trimming frame 80 in the image processing unit 58 when the end button is designated, and controls the image processing unit 58 to execute the trimming display processing. Then, the LCD interface 36 is controlled so that only the LED lit by the processing of step 106 is turned on, and then the light emission control processing program is terminated.

  In step 110B, when the image processing unit 58 has already been set to execute the trimming display process, the above trimming process is not performed.

  FIG. 8B shows an example of a display state on the LCD 38 when the LCD 38 is in use, the power save mode is set, and the trimming mode is set. In the figure, only the LED 60A that illuminates the area of approximately one third of the left end side of the display area of the liquid crystal panel 70 of the LCD 38 is shown.

  As shown in the figure, in this case, since only the LED 60A is turned on, the power consumption required for turning on the LED can be reduced to about one-third compared to that during normal operation. Further, in this case, since only a partial area designated by the user in the display image is cut out and displayed with respect to the area illuminated by the LED 60A, the display image is displayed at the same magnification or enlarged. Therefore, the visibility with respect to the partial region can be further improved.

  As described above in detail, in this embodiment, it is possible to obtain an effect excluding the effect of the reduction mode setting in the first embodiment, and only a partial area of the display image is within the illumination range. Since the display means (in this case, the LCD 38) is controlled so as to display, the display image can be displayed at the same magnification or enlarged, so that the visibility with respect to the partial area can be further improved. .

[Third Embodiment]
In the third embodiment, when the power consumption is desired to be reduced (here, the power save mode is set), and the predetermined display image (here, the menu image) on the LCD 38 is displayed. Will be described in the case where control is performed so that only the LEDs that illuminate the partial area emit light. Note that the configuration of the digital camera 10 according to the third embodiment is the same as that of the digital camera 10 according to the first embodiment (see FIGS. 1 to 4). Omitted.

  Hereinafter, the operation of the digital camera 10 according to the third embodiment when the light emission control function is executed will be described with reference to FIG. FIG. 9 is a flowchart showing a processing flow of the light emission control processing program according to the third embodiment executed by the CPU 40 of the digital camera 10 every predetermined period (here, 1 second). The program is stored in a predetermined area of the memory 48 in advance.

  First, in step 200 of the figure, it is determined whether or not the LCD 38 is being used. If the determination is affirmative, the process proceeds to step 202 to determine whether or not the power save mode is set and negative. If it is determined that the normal operation mode has been set, the process proceeds to step 204.

  In step 204, the LCD interface 36 is controlled so that all of the LEDs 60A to 60C are lit, and then the main light emission control processing program is terminated.

  On the other hand, if the determination in step 202 is affirmative, the process proceeds to step 206, where it is determined whether a predetermined display image (here, the menu image) is displayed on the LCD 38, and the determination is negative. If YES in step 204, the process advances to step 204. If an affirmative determination is made, the process advances to step 208.

  In step 208, the LCD interface 36 is controlled so that only the LEDs that illuminate the display area of the predetermined display image among the LEDs 60A to 60C are turned on, and then the process proceeds to step 210.

  In step 210, it is determined whether or not the display area of the predetermined display image has been changed. If the determination is affirmative, the process returns to step 208 to display the changed predetermined display image of the LEDs 60A to 60C. The LCD interface 36 is controlled again so that only the LEDs that illuminate the area are turned on. If a negative determination is made, the process proceeds to step 212.

  In step 212, it is determined whether or not the display of the predetermined display image has been canceled. If a negative determination is made, the process returns to step 210. If an affirmative determination is made, the light emission control processing program is terminated.

  On the other hand, if a negative determination is made in step 200, the process proceeds to step 216, and the LCD interface 36 is controlled so that all the LEDs 60A to 60C are turned off, and then the light emission control processing program is terminated.

  FIG. 10A shows an example of the display state on the LCD 38 when the predetermined display image (the setup menu image in the figure) is displayed on the LCD 38 and only some of the LEDs emit light. Has been. In the figure, a case where four LEDs 60A to 60D are provided as a plurality of LEDs included in the backlight unit 38A is shown. Further, FIG. 5 shows a case where only the LED 60 </ b> A responsible for illuminating an area of approximately a quarter of the left end side of the display area in the liquid crystal panel 70 of the LCD 38 is caused to emit light.

  As shown in the figure, in this case, since only the LED 60A emits light, the power consumption required to turn on the LED can be reduced to about one-fourth of that during normal operation. However, in this case, it is possible to visually recognize the image portion displayed in the region illuminated by the LED 60A, but it is difficult to visually recognize the image portion displayed in the other region.

  In contrast, in the light emission control processing program according to the third embodiment, as shown in FIGS. 10B and 10C, only the LEDs that illuminate the display area of the predetermined display image emit light. Therefore, in addition to the effect of reducing the power consumption, an effect of reliably viewing the predetermined display image can be obtained.

  As described above in detail, the present embodiment has an effect excluding the effect of controlling the display image in the first embodiment to be displayed within the illumination range by some light emitting means. In addition, a predetermined display image displayed on the display means is displayed on the display means when the power saving mode is desired (here, the power save mode is set) and the display means (here, the LCD 38). Control is performed so that only the light emitting means (here, the LED) that illuminates the partial area when the partial display area is displayed, so that the predetermined display image can be surely visually recognized. it can.

  In each of the above embodiments, the case where at least one of the LEDs 60A to 60C is configured to selectively emit light or not emit light (see FIG. 4) has been described, but the present invention is not limited thereto. For example, in addition to this, the luminance of each LED may be variable.

  FIG. 11 shows a configuration example of the electrical system of the backlight unit 38A in this case. In addition, the same code | symbol as FIG. 4 is attached | subjected to the same component as FIG. 4 of the same figure.

  In the configuration example shown in the figure, as compared with the configuration shown in FIG. 4, a series circuit of three sets of resistors 68 and switches 69 is connected in parallel to the cathode of the LED 60 </ b> A, and The only difference is that the control terminal is connected to the LCD interface 36.

  In this configuration, the number of light emission of each LED and the luminance at the time of light emission can be selectively switched by a combination of the on / off state of the three switches 69 and the connection state of the switch 64A and the switch 64B.

  In this case, the effect of reducing power consumption can be further improved by suppressing the luminance of the LED to emit light to such an extent that the display image can be visually recognized.

  Moreover, in each said embodiment, 38 A of backlight parts were comprised as what can light an LED only with LED60A, two types of LED60A and LED60B, and LED3 of LED60A-all combinations of LED60C. (Refer to FIG. 4.) Although the case has been described, the present invention is not limited to this. For example, the LEDs 60A to 60C can be individually turned on. In this case, since the illumination area by the LED can be set finely as compared with the above embodiments, the convenience can be further improved.

  In each of the above embodiments, the case where the LED is applied as the light emitting means of the present invention has been described. However, the present invention is not limited to this, and has been widely used as a backlight of a liquid crystal display, for example. It is also possible to adopt a form in which the arc tube is applied. Also in this case, the same effects as those of the above embodiments can be obtained.

  In each of the above embodiments, the case where a liquid crystal display is applied as the display means of the present invention has been described. However, the present invention is not limited to this, for example, a plasma display, an organic EL display, a CRT display, or the like. The self-luminous display can be applied. In this case, the light emitting means of the present invention corresponds to the light emitting portion in the display. In this case, the same effects as those of the above embodiments can be obtained.

  In the third embodiment, the case where the menu image is applied as the predetermined display image of the present invention has been described. However, the present invention is not limited to this, for example, by a display unit such as a thumbnail image. Any image can be applied as long as the image is displayed only in a partial region of the display region. Also in this case, the same effects as those of the third embodiment can be obtained.

  In addition, the configuration of the digital camera 10 according to each of the above-described embodiments (see FIGS. 1 to 4 and 11) is merely an example, and it is needless to say that the configuration can be appropriately changed without departing from the gist of the present invention. .

  For example, the number of LEDs (3 or 4) in the backlight unit described in the above embodiments is merely an example, and any number of LEDs can be applied as long as they are plural.

  For example, the LCD shown in each of the above embodiments has an aspect ratio of 16: 9 in the display area. However, the aspect ratio may be any.

  The processing flow of the light emission control processing program described in each of the above embodiments (see FIGS. 5, 7, and 9) is also an example, and can be changed as appropriate without departing from the gist of the present invention. Needless to say.

  Further, although cases have been described with the above embodiments where the present invention is applied to a digital camera, the present invention illuminates display means such as a PDA, mobile phone, personal computer, and the display area of the display means. Needless to say, the present invention can be applied to any information device having a plurality of light emitting means.

It is an external view which shows the external appearance of the digital camera which concerns on embodiment. It is a block diagram which shows the principal part structure of the electric system of the digital camera which concerns on embodiment. It is a front view which shows schematic structure of LCD which concerns on embodiment. It is a circuit diagram which shows the principal part structure of the electric system of the backlight part which concerns on embodiment. It is a flowchart which shows the flow of a process of the light emission control processing program which concerns on 1st Embodiment. It is a figure with which it uses for description of the effect in 1st Embodiment, and is the schematic which shows the example of the light emission state of LED, and the display state example of the display image by LCD. It is a flowchart which shows the flow of a process of the light emission control processing program which concerns on 2nd Embodiment. It is a figure with which it uses for description of the trimming process which concerns on 2nd Embodiment, (A) is a schematic diagram which shows the example of a display state of the display image at the time of setting a trimming area | region, (B) is a power save mode. FIG. 6 is a schematic diagram illustrating an example of a display state on the LCD when is set and a trimming mode is set. It is a flowchart which shows the flow of a process of the light emission control processing program which concerns on 3rd Embodiment. It is a figure with which it uses for description of the effect in 3rd Embodiment, and is the schematic which shows the example of the light emission state of LED, and the display state example of the display image by LCD. It is a circuit diagram which shows the modification of the structure of the electric system of the backlight part which concerns on embodiment. FIG. 10 is a diagram for explaining a problem in the conventional technology, and is a circuit diagram illustrating a configuration example of an electric system in a conventional backlight unit.

Explanation of symbols

10 Digital Camera 36 LCD Interface 38 LCD (Display Means)
38A Backlight section 40 CPU (light emission control means, display control means)
60A-60D LED (light emitting means)
70 LCD panel 80 Trimming frame

Claims (12)

Light emission control for controlling the light emission state of the light emitting means of a display device having display means for displaying an image and a plurality of light emitting means for illuminating different areas in the display area of the display means by emitting light respectively A device,
The plurality of light emitting units are configured to selectively emit at least one of the plurality of light emitting units, and the number of light emission of the plurality of light emitting units is controlled according to a predetermined condition. A light emission control device comprising a light emission control means. The display means is a liquid crystal display,
The light emission control device according to claim 1, wherein the plurality of light emitting units are backlights that illuminate a display area of the liquid crystal display. The light emission control device according to claim 1, wherein the predetermined condition is whether or not the power consumption is desired to be reduced. Display control means for controlling the display means to display a display image by the display means within an illumination range by the light emission means when only a part of the plurality of light emission means emits light by the light emission control means. The light emission control device according to any one of claims 1 to 3, further comprising: 5. The display control unit controls the display unit so that the display image is reduced and displayed in the illumination range, or only a partial region of the display image is displayed in the illumination range. The light emission control apparatus of description. The light emission control means is in a state where it is desired to reduce power consumption as the predetermined condition, and a predetermined display image by the display means is displayed only in a partial area of the display area of the display means. The light emission control device according to claim 3, wherein the light emission means for illuminating the partial area is controlled to emit light. Light emission control for controlling the light emission state of the light emitting means of a display device having display means for displaying an image and a plurality of light emitting means for illuminating different areas in the display area of the display means by emitting light respectively A method,
The plurality of light emitting units are configured to selectively emit at least one of the plurality of light emitting units, and the number of light emission of the plurality of light emitting units is controlled according to a predetermined condition. The light emission control method characterized by the above-mentioned. The display means is a liquid crystal display,
The light emission control method according to claim 7, wherein the plurality of light emitting units are backlights that illuminate a display area of the liquid crystal display. The light emission control method according to claim 7, wherein the predetermined condition is whether or not the power consumption is desired to be reduced. 10. The display means is controlled so that a display image by the display means is displayed within an illumination range by the some light emitting means when only a part of the plurality of light emitting means emits light. The light emission control method of any one of Claims 1. The light emission control method according to claim 10, wherein the display unit is reduced and displayed within the illumination range, or the display unit is controlled to display only a partial region of the display image within the illumination range. If the predetermined condition is a state where it is desired to reduce power consumption, and the predetermined display image by the display means is displayed only in a partial area of the display area of the display means, part thereof The light emission control method according to claim 9, wherein only the light emitting means for illuminating the region is controlled to emit light.

Images