Patent Publication Number: US-2023148145-A1

Title: Liquid crystal display device, electronic apparatus, display control method, display control program, and non-transitory recording medium

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. patent application Ser. No. 16/878,038, filed May 19, 2020, which is a Continuation of U.S. patent application Ser. No. 16/440,804, filed Jun. 13, 2019 (now U.S. Pat. No. 10,761,368, issued on Sep. 1, 2020), which is a Continuation of PCT International Application No. PCT/JP2017/046850 filed on Dec. 27, 2017, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2017-013510 filed on Jan. 27, 2017. Each of the above applications are hereby expressly incorporated by reference in its entirety, into the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a liquid crystal display device, an electronic apparatus, a display control method, and a non-transitory computer-readable recording medium for storing a display control program, and particularly to a technology for improving visibility of liquid crystal display using a TN type liquid crystal display panel (TN: Twisted Nematic) and a light source for backlight. 
     2. Description of the Related Art 
     In a liquid crystal display device, since visibility is changed depending on a configuration of a display device and a condition during observation, various measures are prepared. For example, JP2007-079093A describes a technology for suppressing a change of tint during the switching between illumination angles by switching between a wavelength ranges of light-emitting diodes (LED) to be turned on depending on an angle of view in a light source device which switches between illumination angle ranges and changing a state of an element which switches between a transparent state and a scattering state. 
     JP2003-222833A describes a technology for obtaining favorable-visibility display by using an optical member such as a phase difference plate or a polarization separation element in an STN type (STN: Super Twisted Nematic) liquid crystal display device that performs positive display by using reflection light and performs negative display by using transmission light from a backlight unit. JP2007-011049A describe a technology for suppressing a decrease in contrast by using a λ/4 plate in a semi-transmission type liquid crystal display device capable of performing negative display and positive display by using a backlight unit. JP2003-222833A and JP2007-011049A describe that the “positive display means that black display is performed during voltage application. 
     SUMMARY OF THE INVENTION 
     In a case where backlight is illuminated in a display device using transmission type liquid crystals or semi-transmissive liquid crystals, since transmission wavelength characteristics of the backlight are different depending on an angle (viewing direction), the color of liquid crystal display seems to be changed depending on the angle (tint change). In particular, since the transmission wavelength characteristics of the shielding region (black region) greatly depend on the angle, in a case where the angle is changed, the color seems to be greatly changed. The problem of such a tint change is remarkable in a TN type (TN: Twisted Nematic) liquid crystal display device which is widely used since the TN type liquid crystal display device is able to be driven at a low voltage and is inexpensive. Hereinafter, a tint change of the TN type liquid crystal display device according to the related art will be described. 
       FIG.  18 A  shows a state in which a liquid crystal display panel (it is assumed that the TN type liquid crystal is used) during non-illumination of backlight is viewed from the front. Information (date, ISO: ISO sensitivity, SS: shutter speed, F: F number) is displayed as white (transmission region), and the background is displayed as black (shielding region). Meanwhile,  FIG.  18 B  shows a state in which the same liquid crystal display panel is viewed from the front during the illumination of the backlight. In a background portion which is the shielding region, the tint also seems to be changed (depending on the wavelength range of the backlight, but the tint seems to be in, for example, bluish color) due to the influence of the backlight. As shown in  FIG.  19 A  and  FIG.  19 B , in a case where the liquid crystal display panel of  FIG.  18 B  is viewed in a diagonal direction during the illumination of the backlight ( FIG.  19 A  is viewed in a lower left direction and  FIG.  19 B  is viewed in a lower right direction), the tint is hardly changed in a character portion which is the transmission region of the backlight. However, since the angle of view of the TN type liquid crystal is extremely narrow, the tint of the background region seems to be greatly changed even though the viewing direction is changed a little. 
     In this regard to the problem of the tint change, since multiple kinds of light sources (a white LED and a blue LED) are used depending on the angle of view and the control of a switching element is further controlled in the technology described in JP2007-079093A, the device configuration and control are complicated. In the technologies described in JP2003 -222833A and JP2007-011049A, the configuration is complicated due to the use of the optical member such as the phase difference plate or the polarization separation element, and a method of coping with the tint change depending on the viewing direction is not described. 
     As stated above, in the related art, it is difficult to make the tint change depending on the viewing direction unremarkable in the liquid crystal display device. 
     The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid crystal display device which makes a tint change depending on a viewing direction unremarkable by using a TN type liquid crystal and a light source for backlight, and a display control method of the liquid crystal display device. Another object of the present invention is to provide a non-transitory computer-readable recording medium for storing a display control program causing the liquid crystal display device to perform the display control method 
     In order to achieve the aforementioned objects, a liquid crystal display device according to a first aspect of the present invention comprises: a light source of a backlight that includes light rays of two or more wavelengths; a liquid crystal display panel configured to have a shielding region which shields the backlight and an external incidence ray and a transmission region which transmits the backlight using a Twisted Nematic type liquid crystal; and a processor configured to acquire a first mode or a second mode as a mode of the liquid crystal display panel; and display information having an information display region and a background region on the liquid crystal display panel, wherein the processor further configured to perform first display control in which a region having a larger area of the information display region and the background region is set as the shielding region and a region having a smaller area is set as the transmission region in the first mode; and perform second display control in which the region having the larger area of the information display region and the background region is set as the transmission region and the region having the smaller area is set as the shielding region in the second mode. 
     In order to achieve the aforementioned objects, a display control method according to a seventh aspect of the present invention is a display control method of a liquid crystal display device including a light source of a backlight that includes light rays of two or more wavelengths, and a liquid crystal display panel configured to have a shielding region which shields the backlight and an external incidence ray and a transmission region which transmits the backlight and the external incidence ray using a Twisted Nematic type liquid crystal, the method comprising: acquiring a first mode or a second mode as a mode of the liquid crystal display panel; and displaying information having an information display region and a background region on the liquid crystal display panel based on the acquired mode; wherein the method further comprising: performing first display control in which a region having a larger area of the information display region and the background region is set as the shielding region and a region having a smaller area is set as the transmission region in the first mode; and performing second display control in which the region having the larger area of the information display region and the background region is set as the transmission region and the region having the smaller area is set as the shielding region in the second mode. 
     As described above, according to a liquid crystal display device, an electronic apparatus, a display control method, and a non-transitory computer-readable recording medium for storing a display control program according to the present invention, it is possible to make a tint change depending on a viewing direction unremarkable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram showing a configuration of an imaging apparatus according to a first embodiment of the present invention. 
         FIG.  2    is a top view of the imaging apparatus. 
         FIG.  3    is a block diagram showing the configuration of the imaging apparatus. 
         FIG.  4    is a diagram showing a configuration of a liquid crystal display device. 
         FIG.  5    is a flowchart showing processing of display control according to the first embodiment. 
         FIG.  6    is a flowchart showing processing of first display control. 
         FIG.  7    is a flowchart showing processing of second display control. 
         FIG.  8    is a diagram showing an example of information displayed on the liquid crystal display device. 
         FIG.  9 A  and  FIG.  9 B  are diagrams showing display scenes during non-illumination of backlight and during illumination of the backlight. 
         FIG.  10 A  and  FIG.  10 B  are diagrams showing scenes of a tint change depending on a viewing direction. 
         FIG.  11 A  and  FIG.  11 B  are other diagrams showing the display scenes during the non-illumination of the backlight and during the illumination of the backlight. 
         FIG.  12    is a diagram showing a scene in which a region of interest is set. 
         FIG.  13 A  and  FIG.  13 B  are diagrams showing scenes of display control in an aspect in which the region of interest is set. 
         FIG.  14 A  and  FIG.  14 B  are diagrams showing scenes of the tint change depending on the viewing direction. 
         FIG.  15    is a diagram showing a relationship between an area ratio of a shielding region and a tint change amount. 
         FIG.  16    is a diagram for describing display control with consideration for hysteresis. 
         FIG.  17    is another diagram for describing the display control with consideration for the hysteresis. 
         FIG.  18 A  and  FIG.  18 B  are diagrams for describing display control according to the related art. 
         FIG.  19 A  and  FIG.  19 B  are other diagrams for describing display control according to the related art. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments of a liquid crystal display device, an electronic apparatus, a display control method, a display control program, and a non-transitory recording medium according to the present invention will be described in detail. 
     First Embodiment 
     Configuration of Imaging Apparatus 
       FIG.  1    is a perspective view showing an external appearance of an imaging apparatus  100  (the electronic apparatus and the electronic apparatus main body) according to a first embodiment of the present invention. The imaging apparatus  100  includes an imaging apparatus main body  200  (electronic apparatus main body), and a lens device  300  (electronic apparatus main body) attached to the imaging apparatus main body  200 . The imaging apparatus main body  200  and the lens device  300  are attached to each other by connecting a mount  246  provided at the imaging apparatus main body  200  and a mount  346  (see  FIG.  3   ) of the lens device  300  corresponding to the mount  246 , and is detached from each other by disconnecting these mounts thereof. A flash  240  is provided on a front surface of the imaging apparatus main body  200  in addition to the mount  246 , and a release button  220 - 1 , a dial  220 - 2  for setting an imaging mode, and a top monitor  213  (liquid crystal display device) are provided on a top surface (see  FIG.  2   ). 
       FIG.  3    is a block diagram showing a configuration of the imaging apparatus  100 . Operations of the imaging apparatus  100  is generally controlled by a main CPU  214  (CPU: Central Processing Unit) of the imaging apparatus main body  200  and a lens CPU  340  of the lens device  300 . A program and data required for the operations of the main CPU  214  are stored in a flash ROM  226  and a ROM  228  (ROM: Read Only Memory) within the imaging apparatus main body  200 , and a display control program (a display control program causing a liquid crystal display device  260  to perform a display control method) according to the present invention is recorded in the ROM  228 , as a code readable by the computer (the main CPU  214  and a display controller  210 ). Accordingly, the ROM  228  is an example of the non-transitory recording medium according to the present invention, and recording media such as a hard disk, a magneto-optical recording device such as a digital versatile disk (DVD), or various semiconductor memories can be used as the non-transitory recording medium according to the present invention. A program and data required for operations of the lens CPU  340  are stored in a ROM  344  within the lens CPU  340 . 
     An operation unit  220  including a playback button, a MENU/OK key, a cross key, and a BACK key in addition to the release button  220 - 1  and the dial  220 - 2  is provided at the imaging apparatus main body  200 . A user can issue commands such as selection of the imaging mode or a playback mode, imaging start, selection of an image, playback, deletion, and a zoom command in by operating the buttons and/or the keys included in the operation unit  220 . The user can switch between an illumination mode in which backlight is illuminated and a non-illumination mode in which backlight is not illuminated by operating the buttons and/or the keys. A signal from the operation unit  220  is input to the main CPU  214 . The main CPU  214  controls circuits of the imaging apparatus main body  200  based on the input signal, and transmits and receives signals to and from the lens device  300  through the mount  246  and a mount communication unit  250 . 
     A terminal  247  is provided at the mount  246 , and a terminal  347  is provided at the mount  346 . In a case where the lens device  300  is attached to the imaging apparatus main body  200 , the corresponding terminals  247  and  347  come in contact with each other, and thus, communication can be performed (the terminals  247  and  347  in  FIGS.  1  and  3    are conceptually depicted, and the positions and numbers of the terminals in the imaging apparatus  100  are not limited to these diagrams). 
     Examples of the aforementioned terminals include a ground terminal, a synchronization signal terminal, a serial communication terminal, a control status communication terminal, and a power supply terminal for the units of the lens device  300  from a battery  242  of the imaging apparatus main body  200 . Power supply from the battery  242  is performed under the control of a power supply controller  244 . 
     In the imaging mode, subject light is formed on a light reception surface of an imaging element  202  of the imaging apparatus main body  200  through a zoom lens ZL, a focus lens FL, and a stop I of the lens device  300 . Although it has been described in the first embodiment that the imaging element  202  is a complementary metal-oxide semiconductor (CMOS) type, the imaging element is not limited to the CMOS type. A charge coupled device (CCD) type may be used. The focus lens FL, the zoom lens ZL, and the stop I are driven by a zoom lens controller  310 , a focus lens controller  320 , and a stop controller  330  which are controlled by the lens CPU  340 , and focus control, zoom control, and stop control are performed. 
     The zoom lens controller  310  changes an imaging magnification by moving the zoom lens ZL in an optical axis direction according to a command from the lens CPU  340 . The focus lens controller  320  focuses on a subject by causing the focus lens FL to move back and forth in the optical axis direction according to a command from the lens CPU  340 . The stop controller  330  changes an F number of the stop I according to a command from the lens CPU  340 . 
     In a case where a first-step push operation of the release button  220 - 1  (an operation to push the button halfway through a stroke; also referred to as a “half push operation”) is performed, the main CPU  214  starts auto focus (AF) and auto exposure (AE) operations, and image data output from an A/D converter  204  (A/D: Analog to Digital) is input to an AE/AWB detection unit  224  (AE: Automatic Exposure, AWB: Automatic White Balance) in response to the pushing. The main CPU  214  calculates brightness (imaging Ev value, Ev: Exposure Value) of the subject from an accumulation value of G signals (signals of pixels in which green color filters are arranged) input to the AE/AWB detection unit  224 , and controls the F number of the stop I, a charge accumulation time (corresponding to a shutter speed) in the imaging element  202 , and an emission time of the flash  240  based on the result thereof 
     An AF detection unit  222  is a part that performs contrast AF processing or phase difference AF processing. In a case where the contrast AF processing is performed, the focus lens FL within a lens barrel is controlled such that an AF evaluation value indicating a focusing state is a maximum value which is calculated by integrating high-frequency components of the image data within a focus region. In a case where the phase difference AF processing is performed, the focus lens FL within the lens device  300  is controlled such that a defocus amount obtained from phase difference data calculated by using pixels having a plurality of phase differences within the focus region of the image data is zero. 
     In a case where the AE operation and the AF operation are finished and a second-step push operation of the release button  220 - 1  (a full stroke push operation; also referred to as a “fully push operation”) is performed, the flash  240  is emitted through the control using a flash controller  238 . Based on a readout signal applied from an imaging element controller  201 , signal charges accumulated in the imaging element  202  are read as voltage signals corresponding to the signal charges, and are applied to an analog signal processing unit  203 . The analog signal processing unit  203  samples, holds, and amplifies R signals, G signals, and B signals of pixels by performing correlative double sampling processing on the voltage signals output from the imaging element  202 , and applies the sampled, held, and amplified signals to the A/D converter  204 . The A/D converter  204  converts analog R signals, G signals, and B signals (signals of pixels in which red, green, and blue color filters are arranged) sequentially input into digital R signals, G signals, and B signals, and outputs the converted signals to an image input controller  205 . In a case where the imaging element  202  is the metal oxide semiconductor (MOS) type imaging element, the A/D converter  204  is built in the imaging element  202  in many cases, and the aforementioned correlative double sampling processing is not required. 
     The image data output from the image input controller  205  is input to a digital signal processing unit  206 , and signal processing such as offset processing, gain control processing including white balance correction and sensitivity correction, gamma-correction processing, and YC processing (processing of brightness signals and color difference signals) is performed on the input image data. The image data is written and/or read out to a VRAM  230  (Video RAM), and is encoded by the display controller  210 . The image data is output to a rear monitor  212 , and thus, a subject image is displayed on the rear monitor  212 . 
     In response to the full push operation of the release button  220 - 1 , the image data output from the A/D converter  204  is input to and is temporarily stored in an SDRAM  232  (SDRAM: Synchronous Dynamic Random Access Memory) from the image input controller  205 . After the image data is temporarily stored in the SDRAM  232 , an image file is generated by performing the signal processing such as the gain control processing, the gamma-correction processing, and the YC processing in the digital signal processing unit  206  and compression processing in a compression and decompression processing unit  208  in a Joint Photographic Experts Group (JPEG) format on the image data. The image file is read by a media controller  234 , and is recorded in a memory card  236 . The image recorded in the memory card  236  can be played on displayed by the rear monitor  212  by operating the playback button of the operation unit  220 . Meanwhile, the top monitor  213  displays information such as an operation state and an imaging condition of the imaging apparatus  100  under the control of the display controller  210  (liquid crystal display device, display controller). The display controller  210  and the top monitor  213  constitutes a liquid crystal display device  260  (liquid crystal display device) according to the first embodiment. 
     Configuration of Top Monitor 
       FIG.  4    is a diagram showing a schematic configuration of the top monitor  213 . The top monitor  213  comprises a liquid crystal cell  272 , a transmission-side polarizing plate  274  (polarizing plate), a reflection-side polarizing plate  276  (polarizing plate), and a backlight unit  280  (backlight unit). The liquid crystal cell  272 , the transmission-side polarizing plate  274 , and the reflection-side polarizing plate  276  are constituent elements of a liquid crystal display panel  270  (liquid crystal display panel) according to the first embodiment. The liquid crystal cell  272  uses a TN type liquid crystal (TN: Twisted Nematic), independently sets a shielding region and a transmission region for each dot by applying or not applying a voltage to each dot by using an electrode (not shown), and displays the aforementioned information (the details of display control will be described below). The transmission-side polarizing plate  274  provided on a front side (viewing side) of the liquid crystal cell  272  has a wavelength compensation function, and the reflection-side polarizing plate  276  provided on a rear side (side opposite to the viewing side) does not have the wavelength compensation function. External incidence ray is reflected by the reflection-side polarizing plate  276 . The backlight unit  280  comprises a white LED  280 A (white LED) as a light source of backlight, and a light guide plate  280 B which guides the backlight (including light rays of two or more wavelength ranges) illuminated from the white LED  280 A to the liquid crystal display panel  270 , and is set in the illumination mode in which the backlight is illuminated or the non-illumination mode in which the backlight is not illuminated under the control of the display controller  210  (the switching between the illumination and the non-illumination of the backlight can be performed by the display controller  210  based on a command input by the user through the operation unit  220 ). That is, the liquid crystal display panel  270  is a semi-transmission type liquid crystal display panel capable of using both the reflection of ambient light and the backlight as light sources. The liquid crystal display panel  270  can be a so-called normal white type liquid crystal display panel, but the present invention can also be applied to a normal black type liquid crystal display panel. 
     Hardware Structure of Display Controller 
     In the first embodiment, various processors to be described below can be adopted as a hardware structure for realizing various processing (first display control and second display control in a display control step, and switching control between the illumination and the non-illumination of the backlight) in the display controller  210 . As the various processors, there are a central processing unit (CPU) which is a general-purpose processor which performs various processing by software (program), a programmable logic device (PLD) which is a processor capable of changing a circuit configuration after Field Programmable Gate Array (FPGA) is manufactured, and a dedicated electric circuitry which is a processor having a circuit configuration designed as a dedicated circuit in order to perform specific processing such as an Application Specific Integrated Circuit (ASIC). 
     A function of the display controller  210  may be realized by one of the various processors, or may be realized by the same kind or different kinds of two or more processors (for example, a plurality of FPGAs, or a combination of the CPU and the FPGA). A plurality of functions may be realized by one processor. As the example in which the plurality of functions is realized by one processor, there is a first aspect in which one processor is constituted by a combination of one or more CPUs and software as represented by a computer such as a client or a server, and the processor realizes the plurality of functions. There is a second aspect in which a processor that realizes the functions of the entire system including the plurality of functions by one integrated circuit (IC) chip as represented by a system on chip (SoC) is used. As stated above, the various functions are realized by using one or more of the various processors as the hardware structure. More specifically, the hardware structure of the various processors is an electric circuitry in which circuit elements such as semiconductor elements are combined. 
     In the display controller  210 , the processor or the electric circuitry having such a configuration performs various processing (the step of the display control method) while referring the program (display control program) and the data stored in the flash ROM  226  and the ROM  228 . The VRAM  230  and/or the SDRAM  232  are used as a temporary storage area or a work area at the time of the processing as needed. 
     Processing of Display Control 
     Next, display control in the imaging apparatus  100  having the aforementioned configuration will be described.  FIG.  5    is a flowchart showing processing (display control method) of the display control. In the following example, it is assumed that a date and an imaging condition shown in  FIG.  8    is displayed on the top monitor  213 , as operation state information indicating an operation state of the imaging apparatus  100  (imaging apparatus main body  200  and the lens device  300 ). Specifically, a date is 2017, 1 Jan. Sunday (Sunday, Jan. 1, 2017), ISO sensitivity (ISO: International organization for Standardization) is  200 , a shutter speed SS is 1/60 seconds, and an F number F is 1.4. 
     In a case where the processing of the display control is started, screen design information (for example, the numbers, positions, shapes, and arrangement of information display regions and background regions, and whether to black display on a white background or white display on a black background) is obtained in step S 10 . The screen design information may be obtained by being reads out from the flash ROM  226  and/or the ROM  228  by the display controller  210 , or may be obtained by the display controller  210  in response to a command input of the user through the operation unit  220 . Here, it is assumed that a display pattern (whether or not the transmission region is arranged using the shielding region as a base and vice versa) is also not changed without dividing a display region into the date and the operation state information. In a case where the screen design information is obtained, the display controller  210  obtains the operation state information from each unit of the imaging apparatus  100  in step S 12 . The operation state information is information indicating the operation state of the imaging apparatus  100  (the imaging apparatus main body  200  and the lens device  300 ), and the aforementioned imaging condition is obtained as the operation state information in the first embodiment. In a case where the screen design and the operation state information are obtained, the position, numbers, and arrangement of information display regions and background regions are set based on the screen design and the operation state information (step S 14 ). It is assumed that the “white” in the following description means a color of the liquid crystal display panel  270  in a state in which the backlight and/or the external incidence ray reflected by the reflection-side polarizing plate  276  is transmitted and the “black” means a color of the liquid crystal display panel  270  in a state in which the light is shielded. 
     In step S 16 , it is determined whether or not the backlight unit is in the non-illumination mode (whether the backlight is illustrated or is not illustrated). For example, this determination can be performed by the display controller  210  based on a command input by the user through the operation unit  220 . In a case where the determination result is positive (in a case of the non-illumination mode), the processing proceeds to step S 18 , and the first display control is performed. In a case where the determination result is negative (the case of the illumination mode), the processing proceeds to step S 20 , and the second display control is performed. The information (the aforementioned date and imaging condition) is displayed depending on the result of the first or second display control (step S 22 ; display control step). 
       FIG.  6    is a flowchart showing processing of the first display control (the display control in the non-illumination mode; display control step). In the first display control, it is determined which region of the information display region and the background region has a larger area (whether or an area of the information display region is larger than an area of the background region) (step S 30 ). In a case where the determination result is positive, the processing proceeds to step S 32 . The information display region of which the area is larger is set as the shielding region, and the background region of which the area is smaller is set as the transmission region (the black display on the white background). Meanwhile, in a case where the determination result in step S 30  is negative, the processing proceeds to step S 34 . The information display region of which the area is smaller is set as the transmission region, and the background region of which the area is larger is set as the shielding region (the white display on the black background). 
     Meanwhile,  FIG.  7    is a flowchart showing processing of the second display control (the display control in the illumination mode; display control step). In the second display control, it is determined which region of the information display region and the background region has a larger area (whether or not the area of the information display region is larger than the area of the background region) (step S 40 ). In a case where the determination result is positive, the processing proceeds to step S 42 . The information display region of which the area is larger is set as the transmission region, and the background region of which the area is smaller is set as the shielding region (the white display on the black background). Meanwhile, in a case where the determination result in step S 40  is negative, the processing proceeds to step S 44 . The information display region of which the area is smaller is set as the shielding region, and the background region of which the area is larger is set as the transmission region (the black display on the white background). 
     In the example of  FIG.  8   , the area of the information display region is smaller than the area of the background region. Thus, in the non-illumination mode, the background region of which the area is larger is set as the shielding region (a black display portion in  FIG.  9 A ) and the information display region of which the area is smaller is set as the transmission region (a white display portion in  FIG.  9 A ) through the first display control (see  FIG.  6   ). Meanwhile, in the illumination mode, the background region of which the area is larger is set as the transmission region (a white display portion in  FIG.  9 B ) and the information display region of which the area is smaller is set as the shielding region (a black display portion in  FIG.  9 B ) through the second display control (see  FIG.  7   ) (steps S 40  and S 44 ). Through such display control, a tint change caused by an angle (viewing direction) in the illumination mode is as shown in  FIG.  10 A  and  FIG.  10 B  ( FIG.  10 A  is a state viewed in a lower left direction and  FIG.  10 B  is a state viewed in a lower right direction; a difference in tint is represented by a difference in hatched portion). Although there is the tint change depending on the viewing direction in the illumination mode, the information display region (character portion) of which the area is smaller is set as the shielding region through the aforementioned second display control and thus, white light is transmitted through the background region of which the area is larger. Accordingly, a change in tint is not remarkable in the aforementioned second display control. It is possible to obtain such an effect with a simple configuration without using an additional optical member. 
     In the aforementioned first and second display control, the information display region may be set as the shielding region, and the background region may be set as the transmission region. Conversely, the information display region may be set as the transmission region, and the background region may be set as the shielding region. 
     The information such as the operation state information may not be displayed by characters and numbers as shown in  FIGS.  9 A,  9 B,  10 A and  10 B , and may be displayed by figures, symbols, or graphs.  FIG.  11 A  and  FIG.  11 B  are diagrams showing an example of a histogram of a captured image. A horizontal axis represents brightness of the captured image, and a vertical axis represents the number of pixels. In the example of  FIG.  11 A  and  FIG.  11 B , the area of the information display region (a lower side of a curve C 1  representing the histogram) is larger than the areas of the background region (an upper side of the curve C 1 ). Thus, in the non-illumination mode, the information display region of which the area is larger is set as the shielding region and the background region of which the area is smaller is set as the transmission region through the first display control ( FIG.  11 A ; the black display on the white background). Meanwhile, contrary to the non-illumination mode, in the illumination mode, the information display region of which the area is larger is set as the transmission region, and the background region of which the area is smaller is set as the shielding region ( FIG.  11 B ; the white display on the black background). Similarly to the example described in  FIGS.  8 ,  9 A,  9 B,  10 A and  10 B , the tint change depending on the viewing direction in the illumination mode ( FIG.  11 B ) is caused depending on the display control. However, the change in tint is not remarkable since the background region of which the area is smaller is set as the shielding region by the forementioned first and second display control. 
     Example of Display Control in Region of Interest 
     Although it has been described in the example of  FIGS.  8  to  10    that the display pattern is also not changed without dividing the display region into the date and the imaging condition (operation state information), the display pattern may be changed by dividing the display region into the date and the imaging condition. For example, as shown in  FIG.  12   , a region of interest (ROI) in which the imaging condition as the operation state information is displayed is provided in a part of the display region, and the date (the information other than the operation state information) is displayed in a region other than the region of interest ROI. The display pattern (for example, whether the information display region or the background region is set as the transmission region or the shielding region, that is, whether to perform the white display on the black background or the black display on the white background) is changed by dividing the display region into the region of interest ROI and the other region. For example, during the non-illumination of the backlight, in the region of interest, a character portion (information display region) is displayed as the transmission region, and a background portion (background region) is displayed as the shielding region (the white display on the black background). In the region other than the region of interest, the character portion is displayed as the shielding region, and the background portion is displayed as the transmission region (the black display on the white background). As stated above, the display pattern is changed by dividing the display region into the region of interest and the other region, and thus, it is possible to easily view the information (imaging condition) in which the content is changed during imaging and for which the attention of the user is high. 
     In a case where the aforementioned region of interest is provided, it is possible to perform the first and second display control depending on the ratio of the information display region to the region of interest. For example, in  FIG.  13 A , and  FIG.  13 B , since the area of the background region (black portion) is larger than the area of the information display region (in which the imaging condition as the operation state information is displayed; white portion) in the region of interest ROI, the first and second display control are performed in the region of interest ROI. Specifically, during the non-illumination of the backlight, the first display control is performed in the region of interest ROI, and the display control is in a display state shown in  FIG.  13 A . During the illumination of the backlight, the second display control is performed, and the display control is in a display state shown in  FIG.  13 B . Accordingly, scenes of the tint change depending on the viewing direction during the illumination of the backlight are as shown in  FIG.  14 A  and  FIG.  14 B  ( FIG.  14 A  is a state viewed in the lower left direction and  FIG.  14 B  is a state viewed in the lower right direction; a difference in tint is represented by a difference in hatched portion), and thus, it is possible to make the tint changes depending on the viewing direction unremarkable. 
     Setting of Threshold Value depending on Allowable Value of Tint Change 
     In the imaging apparatus  100  having the aforementioned configuration, a threshold value may be set with consideration for an allowable value of the tint change and the display control may be performed based on the set threshold value as in the following example. 
       FIG.  15    is a conceptual diagram showing a relationship between an area ratio Sb of the shielding region and the tint change amount during the illumination of the backlight. The “area ratio Sb of the shielding region” in  FIG.  15    can be associated with the “ratio of the area at which the information display region occupies” as the “ratio of the area of the larger one of the information display region and the background region to the area of the entire display region (or the region of interest) during the illumination of the backlight”. For example, the tint change amount can be obtained by quantifying a percentage of persons who feel that “tint is changed” in sensory evaluation for a specific number of persons, and an area ratio at which the tint change amount exceeds an allowable value MAX can be set as a threshold value for the shielding region. 
     In a case where the threshold value is set, it is determined which one of the information display region and the background region is set as the shielding region or which one is set as the transmission region such that the ratio of the shielding region does not exceed the set threshold value (third display control). For example, in a case where the ratio of the area of the larger one of the information display region and the background region is larger than the threshold value, the region of which the area is larger is set as the transmission region, and the region of which the area is smaller is set as the shielding region (third display control). In a case where the ratio of the area of the larger one thereof is equal to or smaller than the threshold value, any region thereof may be set as the shielding region. For example, the region of which the area is larger can be set as the transmission region, and the region of which the area is smaller can be set as the shielding region. In this case, the transmission region and the shielding region may be set such that the screen design (the pattern of the white and black display) during the non-illumination of the backlight is maintained. 
     The allowable value and the threshold value may be different in a plurality of screen designs (for example, a plurality of screen designs in which at least one of the number, positions, or shapes of information display regions is different). For example, in  FIG.  15   , a threshold value TH1 is used in a design 1, and a threshold value TH2 is used in a design 2 (it is assumed that the allowable values MAX of the tint changes are equal to each other in the designs 1 and 2). Since an area region in which the user has an interest is not the entire display region in some cases, the threshold value may be set for a part of the display region like the aforementioned region of interest. The threshold value may be set in response to a command input by the user (direct input or selection) through the operation unit  220 . The screen designs in association with the threshold values may be stored in the flash ROM  226 , the ROM  228 , and the display controller  210 , and the threshold value may be set depending on the screen design. 
     Display Control With Consideration For Hysteresis 
     Since the information such as the operation state information is changed during the use of the imaging apparatus  100 , the ratio of the area at which the shielding region occupies may be larger than or smaller than the threshold value. In such a situation, the display may be switched whenever the relationship (whether the ratio is larger or smaller than the threshold value) between the ratio and the threshold value is changed. However, the display pattern is frequently changed depending on the use situations (the kind of the information to be displayed or the setting of the imaging condition) of the imaging apparatus  100 , and thus, there is a possibility that it will be difficult to view the display. Thus, it is possible to perform the display control with consideration for the hysteresis (history) of the ratio of the area at which the shielding region occupies as will be described below. 
     In examples shown in  FIGS.  16  and  17   , an upper limit value (X+α) and a lower limit value (X−α) are set as a threshold value X of the area ratio Sb. In a case where the area ratio Sb becomes large (for example, monotonically increases) from a state (Sb&lt;(X−α)) in which the area ratio is smaller than the lower limit value (X−α) and exceeds the upper limit value (X+α) (Sb&gt;(X+α)) in the illumination mode, the display is reversed (from the black display on the white background to the white display on the black background; fourth display control). In  FIG.  17   , changes at timings t1 and t3 correspond to such a case. Similarly, in a case where the area ratio Sb becomes small (for example, monotonically decreases) from a state (Sb&gt;(X+α)) in which the area ratio is larger than the upper limit value (X +a) and is smaller than the lower limit value (X−α) (Sb&lt;(X−α)), the display is reversed (from the white display on the black background to the black display on the white background; fifth display control). In the example of  FIG.  17   , a change at a timing t2 corresponds to such a case. In a case where these conditions are not satisfied (for example, changes at timings t4 and t5), the display is not switched even though the relationship between the area ratio Sb and the threshold value is changed. Through such display control, it is possible to perform easy-to-see display by suppressing a frequent change of the display pattern while making the tint change depending on the viewing direction unremarkable. 
     Another Aspect of Present Invention 
     In addition to the aforementioned first to ninth aspects, tenth to sixteenth aspects to be described below are also included in the present invention. In the tenth to sixteenth aspects, it is assumed that the same descriptions as those in the first to ninth aspects mean the same configurations. 
     Tenth Aspect 
     A liquid crystal display device according to a tenth aspect comprises a semi-transmission type liquid crystal display panel using TN type liquid crystals, a backlight unit that is set in an illumination mode in which backlight including light rays of two or more wavelength ranges is illuminated or a non-illumination mode in which the backlight is not illuminated, and a display controller that displays information on the liquid crystal display panel by setting, as an information display region, one of a shielding region which shields the backlight and an external incidence ray and a transmission region which transmits the backlight and the external incidence ray and setting the other one as a background region. The display controller performs first display control in which a region having a larger area of the information display region and the background region is set as the shielding region and a region having a smaller area is set as the transmission region in the non-illumination mode, and performs third display control in which the region having the larger area is set as the transmission region and the region having the smaller area is set as the shielding region in a case where a ratio of the area at which the larger one of the information display region and the background region occupies the total display region of the liquid crystal display panel is larger than a threshold value in the illumination mode. 
     Eleventh Aspect 
     An eleventh aspect is different from the tenth aspect in that a display controller sets a different threshold value for each of a plurality of display aspects in which at least one of the number, positions, or shapes of information display regions on a liquid crystal display panel is different. 
     Twelfth Aspect 
     A twelfth aspect is an electronic apparatus comprising an electronic apparatus main body and the liquid crystal display device according to the tenth or eleventh aspect. The liquid crystal display device displays, as information, operation state information indicating an operation state of the electronic apparatus main body. 
     Thirteenth Aspect 
     A thirteenth aspect is different from the twelfth aspect in that a display controller performs first display control and third display control in a region of interest which is set for a part of a display region of a liquid crystal display panel and in which operation state information indicating an operation state is displayed. 
     Fourteenth Aspect 
     A display control method according to a fourteenth aspect is a display control method of a liquid crystal display device comprising a semi-transmission type liquid crystal display panel using a TN type liquid crystal and a backlight unit that is set in an illumination mode in which backlight including light rays of two or more wavelength ranges is illuminated or a non-illumination mode in which the backlight is not illuminated. The display control method includes a display controller that displays information on the liquid crystal display panel by setting, as an information display region, one of a shielding region which shields the backlight and an external incidence ray and a transmission region which transmits the backlight and the external incidence ray and setting the other one as a background region. In the display control step, first display control in which a region having a larger area of the information display region and the background region is set as the shielding region and a region having a smaller area is set as the transmission region is performed in the non-illumination mode, and third display control in which the region having the larger area is set as the transmission region and the region having the smaller area is set as the shielding region in a case where a ratio of the area at which the larger one of the information display region and the background region occupies the total display region of the liquid crystal display panel is larger than a threshold value is performed in the illumination mode. 
     Fifteenth and Sixteenth Aspects 
     A display control program according to a fifteenth aspect causes a liquid crystal display device to perform the display control method according to the fourteenth aspect. A non-transitory recording medium according to a sixteenth aspect is a non-transitory recording medium recording a computer-readable code of the display control program according to the fifteenth aspect. 
     While the aspects of the present invention have been described, the present invention is not limited to the aforementioned aspects, and can be variously modified without departing from the gist of the present invention. For example, although it has been described in the aforementioned imaging apparatus  100  that the white LED  280 A is used as the light source of the backlight, the present invention is not limited to the white LED, and can be applied to a light source which illuminates light rays of two or more wavelength ranges (for example, a red wavelength range and a blue wavelength range). In such a light source, transmission characteristics are different depending on a wavelength even at the same angle (viewing direction), and thus, the tint seems to be changed. However, it is possible to make the tint change unremarkable by performing the display control according to the present invention. 
     EXPLANATION OF REFERENCES 
       100 : imaging apparatus 
       200 : imaging apparatus main body 
       201 : imaging element controller 
       202 : imaging element 
       203 : analog signal processing unit 
       204 : A/D converter 
       205 : image input controller 
       206 : digital signal processing unit 
       208 : compression and decompression unit 
       210 : display controller 
       212 : rear monitor 
       213 : top monitor 
       214 : main CPU 
       220 : operation unit 
       220 - 1 : release button 
       220 - 2 : dial 
       222 : AF detection unit 
       224 : AE/AWB detection unit 
       226 : flash ROM 
       228 : ROM 
       230 : VRAM 
       232 : SDRAM 
       234 : media controller 
       236 : memory card 
       238 : flash controller 
       240 : flash 
       242 : battery 
       244 : power supply controller 
       246 : mount 
       247 : terminal 
       250 : mount communication unit 
       260 : liquid crystal display device 
       270 : liquid crystal display panel 
       272 : liquid crystal cell 
       274 : transmission-side polarizing plate 
       276 : reflection-side polarizing plate 
       280 : backlight unit 
       280 A: white LED 
       280 B: light guide plate 
       300 : lens device 
       310 : zoom lens controller 
       320 : focus lens controller 
       330 : stop controller 
       340 : lens CPU 
       344 : ROM 
       346 : mount 
       347 : terminal 
     F: F number 
     FL: focus lens 
     I: stop 
     MAX: allowable value 
     ROI: region of interest 
     S 10  to S 44 : steps of display control method 
     Sb: area ratio 
     SS: shutter speed 
     X: threshold value 
     ZL: zoom lens