JP2007025617A - Contrast adjustment device, contrast adjustment method and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contrast adjustment device having an A/D conversion means capable of adjusting contrast, a contrast adjustment method in the contrast adjustment device and a display device. <P>SOLUTION: A second analog video signal is input in a second A/D conversion part 312. A microcomputer 200 outputs reference voltage VRH to be reference in digital conversion to the second conversion part 312. The reference voltage VRH is varied by the microcomputer 200. A second digital video signal output from the second A/D conversion part 312 can take digital value different from one another depending on the reference voltage VRH. A second video image whose contrast is adjusted is displayed by a TFT 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a contrast adjustment device having an A / D conversion means for converting an analog video signal into a digital video signal, a contrast adjustment method in the contrast adjustment device, and a display device. Specifically, the present invention relates to a contrast adjustment device that performs contrast adjustment by changing a reference voltage during A / D conversion.

  2. Description of the Related Art Conventionally, a multi-view display device has been proposed in which individual images for a plurality of viewing directions can be simultaneously displayed on the same display device.

Such a function is, for example, displayed in such a manner that pixels of two different images are alternately arranged in units of pixels on one horizontal scanning line in the liquid crystal screen, and alternately with a predetermined pixel width in the vertical direction of the screen in front of the liquid crystal screen. This is realized by providing a slit barrier having a slit and separately displaying two different images depending on the viewing position of the liquid crystal screen (for example, Patent Document 1 below).
Japanese Patent No. 3194024, especially FIG.

  However, when such a multi-view display device is applied to a car navigation device, since the vehicle travels in various situations, the brightness and darkness of both images displayed for the driver seat and the passenger seat are displayed. It has been desired to provide a multi-view display device with a so-called contrast adjustment function for adjusting (whiteness, blackness).

  In addition, it is more convenient if such a contrast adjustment function can be used for various devices other than the multi-view display device.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a contrast adjustment device having an A / D conversion means capable of performing contrast adjustment, a contrast adjustment method in the contrast adjustment device, and a display device.

  In order to achieve the above object, the present invention provides an A / D conversion means for converting an analog video signal into a digital video signal in a contrast adjusting device, and a reference for the conversion input to the A / D conversion means. The A / D conversion means outputs the digital video signal whose contrast is adjusted based on the reference voltage.

  Further, the present invention is characterized in that the contrast adjusting device further comprises control means for making the reference voltage variable.

  Furthermore, the present invention provides the contrast adjustment device, wherein the A / D conversion means is configured to change the digital image of the digital image signal based on the reference voltage so that the contrast is adjusted. A signal is output.

  Furthermore, in the contrast adjustment device according to the present invention, when the control unit outputs a first reference voltage to the A / D conversion unit, the A / D conversion unit is configured to adjust the contrast based on the reference. When the digital video signal is output and the control means outputs a second reference voltage higher than the first reference voltage to the A / D conversion means, the A / D conversion means has the contrast of the reference When the digital video signal adjusted to be darker is output and the control means outputs a third reference voltage lower than the first reference voltage to the A / D conversion means, the A / D conversion means Outputs the digital video signal with the contrast adjusted to be brighter than the reference.

  In order to achieve the above object, the present invention provides a contrast adjustment method for a contrast adjustment apparatus comprising an A / D conversion means for converting an analog video signal into a digital video signal based on a reference voltage, wherein the reference voltage is variable. Thus, the digital video signal whose contrast has been adjusted is output from the A / D conversion means.

  Furthermore, in order to achieve the above object, the present invention provides a display device capable of displaying individual videos for a plurality of viewing directions on the same screen, and corresponding to at least one of the plurality of videos. A / D conversion means for inputting an analog video signal to be converted into a digital video signal, and control means for outputting a reference voltage serving as a reference for the conversion to the A / D conversion means, the control means Is characterized in that the digital video signal whose contrast is adjusted is output from the A / D conversion means by making the reference voltage variable.

  ADVANTAGE OF THE INVENTION According to this invention, the contrast adjustment apparatus which has an A / D conversion means which can perform contrast adjustment, the contrast adjustment method in this contrast adjustment apparatus, and a display apparatus can be provided.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to these embodiments, but extends to the invention described in the claims and equivalents thereof.

[Overall configuration of display device and description of each configuration]
First, the overall configuration of the display device according to the present invention will be described. FIG. 1 is a conceptual diagram of a display device according to the present invention.

  The conceptual diagram of FIG. 1 shows the first display image according to the relative position of the observers (users) 10 and 11 with respect to the display unit 7, in other words, according to the viewing angle with respect to the display unit 7. 8, the observer 11 can view the second display image 9 substantially simultaneously, and the display images 8 and 9 can be viewed over the entire display surface of the display unit 7 conceptually. Show. In FIG. 1, a first image source 1 is, for example, a movie image of a DVD player, a received image of a television receiver, or the like, and a second image source 2 is, for example, a map or route guidance image of a car navigation device. The first image data 3 and the second image data 4 are supplied to the display control unit 5 and processed so that they can be displayed on the display unit 7 substantially simultaneously.

The display unit 7 to which the display data 6 is supplied from the display control unit 5 includes a liquid crystal panel provided with a parallax barrier described later. Half of the total number of pixels in the horizontal direction of the display unit 7 is displayed on the first display image 8 based on the first image source 1, and the other half of the pixels is the second display image 9 based on the second image source 2. Used for display. The observer 10 located on the left side with respect to the display unit 7 can see only the pixels corresponding to the first display image 8, and the second display image 9 is blocked by the parallax barrier formed on the surface of the display unit 7. Is virtually invisible. On the other hand, the observer 11 located on the right side of the display unit 7 can see only the pixels corresponding to the second display image 9, and the first display image 8 is blocked by the parallax barrier and is not substantially visible. In addition, about the parallax barrier, the structure disclosed by the following patent documents 2 and patent documents 3 is applicable, for example.
JP-A-10-123461 JP-A-11-84131

With such a configuration, different information and content can be provided to the left and right users on a single screen. Of course, if the first and second image sources 1 and 2 are the same, the left and right users can view the same image as before.

  FIG. 2 is a perspective view showing an example of mounting the multi-view display device according to the present invention on a vehicle. In the figure, a driver's seat 13 is disposed on the right side, and a passenger seat 12 is disposed on the left side. A windshield 14 is provided in front of the driver seat 13 and the passenger seat 12.

  The display unit 7 of the multi-view display device of FIG. 1 is arranged in the dashboard portion at the substantially center between the driver's seat 13 and the passenger seat 12 as shown in FIG. Various operations on the multi-view display device are performed by operating a touch panel (not shown) integrally formed on the surface of the display unit 7, the operation unit 15, or an infrared or wireless remote controller (not shown). A speaker 16 is disposed at each door of the vehicle, and sounds, warnings, and the like linked to the display image are output.

  The observer 11 shown in FIG. 1 sits in the driver seat 13 and the observer 10 sits in the passenger seat 12. The image that can be viewed from the first viewing direction (driver's seat side) with respect to the display unit 7 is, for example, an image such as a map of a car navigation device, and can be viewed from the second viewing direction (passenger seat side) substantially simultaneously. Possible images are, for example, television reception images and DVD movie images. Therefore, the passenger in the passenger seat 12 can enjoy television and DVD at the same time that the driver in the driver seat 13 receives driving assistance by car navigation. In addition, since each image is displayed using, for example, the entire 7-inch screen, the screen size is not reduced as in the conventional multi-window display. In other words, optimal information and contents are provided to the driver and passengers as if there were independent dedicated displays.

  FIG. 3 is a schematic view of a cross-sectional structure of the display unit 7. As shown in FIG. 3, the display unit 7 includes a backlight 101 and a liquid crystal panel 100. The liquid crystal panel 100 includes a polarizing plate 102 disposed on the backlight 101 side, a polarizing plate 103 disposed on the front surface on the light emitting direction side of the liquid crystal panel 100, a TFT (Thin Film Transistor) substrate 104, a liquid crystal layer 105, And a color filter substrate 106, a glass substrate 107, and a parallax barrier 108. The liquid crystal panel 100 includes a pair of substrates having a liquid crystal layer 105 sandwiched between a TFT substrate 104 and a color filter substrate 106 disposed to face the TFT substrate 104, a parallax barrier 108 disposed in front of the light emitting direction, and a glass substrate. 107 is sandwiched between two polarizing plates 102 and 103, and is arranged slightly isolated from the backlight 101. In addition, the liquid crystal panel 100 includes pixels composed of RGB colors (three primary colors).

  Each pixel of the liquid crystal panel 100 is displayed and controlled separately for left side (passenger seat side) display and right side (driver seat side) display. The display pixel on the left side (passenger seat side) is blocked from being displayed on the right side (driver seat side) by the parallax barrier 108 and is visible from the left side (passenger seat side). Further, the display pixel on the right side (driver's seat side) is blocked from being displayed on the left side (passenger seat side) by the parallax barrier 108 and is visible from the right side (driver's seat side). This makes it possible to provide different displays for the driver and passengers. In other words, navigation map information can be given to the driver, and at the same time, a DVD movie or the like can be shown to the passenger. Note that if the configuration of each pixel of the parallax barrier 108 and the liquid crystal panel 100 is changed, a configuration in which different images are displayed in a plurality of directions such as three directions is also possible. In addition, the parallax barrier 108 itself may be configured with a liquid crystal shutter or the like that can be electrically driven to change the viewing angle.

  FIG. 4 is a schematic view of the structure of the display panel viewed from the front, and FIG. 3 is a cross-sectional view taken along the line A-A ′ in FIG. 4. In the figure, a pixel 109 is a pixel for left side (passenger seat side) display, and a pixel 110 is a pixel for right side (driver seat side) display. 3 and 4 show a part of the liquid crystal panel 100 in which, for example, 800 pixels are arranged in the horizontal direction and 480 pixels are arranged in the vertical direction. The left (passenger side) display pixel 109 and the right (driver's side) display pixel 110 are grouped in the vertical direction and are arranged alternately. The parallax barriers 108 are arranged at intervals in the horizontal direction and are uniform in the vertical direction. Thereby, when the display panel is viewed from the left side, the parallax barrier 108 covers the right side pixel 110 and the left side pixel 109 is visible. Similarly, when viewed from the right side, the parallax barrier 108 covers the left pixel 109 and the right pixel 110 can be seen. Further, in the vicinity of the front, since both the left pixel 109 and the right pixel 110 are visible, the left display image and the right display image appear to substantially overlap. Here, the left side pixels 109 and the right side pixels 110 alternately arranged in FIG. 4 have RGB colors as shown in FIG. 3, but in each group in the vertical direction, R columns, G columns, B It may be configured as a single color like a column, or may be configured as a column in which a plurality of RGB are mixed.

  FIG. 5 is a circuit diagram showing a schematic diagram of the TFT substrate 104. The TFT substrate 104 includes a display panel driving unit 111, a scanning line driving circuit 112, a data line driving circuit 113, a TFT element 114, data lines 115 to 118, scanning lines 119 to 121, and a pixel electrode 122.

  As shown in FIG. 5, a plurality of subpixels 123 are formed with a region surrounded by the data lines 115 to 118 and the scanning lines 119 to 121 as a unit. In each subpixel, a pixel electrode 122 for applying a voltage to the liquid crystal layer 105 and a TFT element 114 for controlling the switching are formed. The display panel driver 111 controls the drive timing of the scanning line driver circuit 112 and the data line driver circuit 113. The scanning line driving circuit 112 performs a selection operation of the TFT element 114, and the data line driving circuit 113 controls the voltage applied to the pixel electrode 122.

  The plurality of sub-pixels may include first pixel data (for example, data lines 115 and 117) based on synthesized data of first image data and second image data, or first and second individual image data. By transmitting the second pixel data (for right image display) to the data lines 116 and 118, the first image data group for displaying the first image and the second image are displayed. A second image data group to be displayed is formed.

  FIG. 6 is a block diagram showing an outline of a display device according to the present invention, which is an application example to a so-called Audio Visual Navigation multifunction peripheral. The display device includes a touch panel 124, a control unit 200, a CD / MD playback unit 201, a radio reception unit 202, a TV reception unit 203, a DVD playback unit 204, an HD (Hard Disk) playback unit 205, a navigation unit 206, a distribution circuit 207, A first image adjustment circuit 208, a second image adjustment circuit 209, an audio adjustment circuit 210, an image output unit 211, a VICS (Vehicle Information and Communication System) information reception unit 212, a GPS (Global Positioning System) information reception unit 213, Selector 214, operation unit 215, remote control transmission / reception unit 216, remote control 217, memory 218, external audio / video input unit 219, camera 220, brightness detection unit 221, occupant detection unit 222, rear display unit 223, ETC (Electronic Toll Collection) ) The vehicle-mounted device 224 and the communication unit 225 are provided.

  The display unit 7 includes a touch panel 124, a liquid crystal panel 100, and a backlight 101. As described above, the liquid crystal panel 100 of the display unit 7 substantially simultaneously displays an image viewed from the driver's seat side as the first viewing direction and an image viewed from the passenger seat side as the second viewing direction. It is possible to display. The display unit 7 may be a flat panel display other than the liquid crystal panel 100, such as an organic EL (Electro-Luminescence) display panel, a plasma display panel, a cold cathode flat panel display, or the like.

  Images and audio from various sources (CD / MD playback unit 201, radio reception unit 202, TV reception unit 203, DVD playback unit 204, HD playback unit 205, and navigation unit 206) are based on instructions from the control unit 200. If the image source specified for left is distributed to the first image adjustment circuit 208 and the distribution source 207 for distributing the source specified for right to the second image adjustment circuit 209 is the first image if it is an image. If it is a sound, it is distributed to the adjustment circuit 208 and the second image adjustment circuit 209, respectively, to the sound adjustment circuit 210. Then, the first and second image adjustment circuits 208 and 209 adjust the brightness, color tone, and contrast, and cause the image output unit 211 to display the adjusted images on the display unit 7. In addition, the sound adjustment circuit 210 adjusts the distribution, volume, and sound to each speaker, and the adjusted sound is output from the speaker 16.

  FIG. 7 is a block diagram illustrating an outline of the image output unit 211. For example, as shown in FIG. 7, the image output unit 211 includes a first writing circuit 226, a second writing circuit 227, a VRAM (Video RAM) 228, and a display panel driving unit 111. For example, the first writing circuit 226 includes image data corresponding to an odd-numbered column of images output from the first image adjustment circuit 208 among the adjusted image data (that is, the first display image 8 in FIG. 1). 2), the second writing circuit 227 outputs image data corresponding to the even-numbered columns output from the second image adjustment circuit 209 (that is, image data for the second display image 9 in FIG. 1). Is written in the corresponding area in the VRAM 228 respectively. The display panel driving unit 111 is a circuit that drives the liquid crystal panel 100, and the liquid crystal display panel 100 is based on the image data (the combined data of the first image data and the second image data) held in the VRAM 228. Drive the corresponding pixel. Note that since the image data is written in the VRAM 228 so as to correspond to the multi-view display image obtained by combining the first image data and the second image data, one drive circuit may be used. The operation is also the same as that of a driving circuit of a normal liquid crystal display device. Further, as another configuration, the first display panel drive that drives the corresponding pixel of the liquid crystal display panel 100 based on each image data without combining the first image data and the second image data. It is also conceivable to use a circuit and a second display panel driving circuit.

  Here, an example of various sources shown in FIG. 6 will be described. When the HD playback unit 205 is selected, music data such as MP3 files and image data such as JPEG files stored in the hard disk (HD), navigation data, etc. The map data and the like are read out, and menu display and image data for selecting music data can be displayed on the display unit 7.

  The navigation unit 206 includes a map information storage unit that stores map information used for navigation, obtains information from the VICS information reception unit 212 and the GPS information reception unit 213, and creates an image for the navigation operation. Can be displayed. Also, the TV receiving unit 203 receives an analog TV broadcast wave or a digital TV broadcast wave from the antenna via the selector 214.

  FIG. 8 is a block diagram illustrating an outline of the control unit 200.

  The control unit 200 controls the distribution circuit 207 and various sources, and displays the selected two sources or one source. The control unit 200 also displays an operation menu display for controlling these various sources on the display unit 7. Here, as illustrated in FIG. 8, the control unit 200 is configured by a microprocessor or the like, and includes a CPU 230 that comprehensively controls each unit and each circuit in the display device via the interface 229. The CPU 230 is provided with a program storage unit 231 including a ROM that stores various programs necessary for the operation of the display device, and a data storage unit 232 including a RAM that stores various data. Note that the ROM, RAM, and the like can be used either those built in the CPU 230 or those provided externally. The ROM may be an electrically rewritable nonvolatile memory such as a flash memory.

  The user controls the various sources by using the operation unit 215 to perform an input operation or a selection operation such as voice recognition or a switch provided around the touch panel 124 attached to the surface of the display unit 7 or the display unit 7. be able to. Further, an input or selection operation may be performed by the remote controller 217 via the remote controller transmission / reception unit 216. The control unit 200 performs control including various sources in accordance with the operation of the touch panel 124 and the operation unit 215. Moreover, the control part 200 is comprised so that each audio | voice volume etc. of the speaker 16 with which the inside of a vehicle was equipped like FIG. In addition, the control unit 200 stores various setting information such as image quality setting information, a program, and vehicle information in the memory 218.

  FIG. 9 is a block diagram showing an outline of the memory 218.

  For example, as shown in FIG. 9, the memory 218 includes a first screen RAM 233 and a second screen RAM 234 in which adjustment values of image quality of the first image and the second image set by the user can be written. Also, image quality setting information storage means 235 in which a plurality of image quality adjustment values are stored in advance for each image quality adjustment as preset values that can be read out when adjusting the image quality of the first image and the second image. Have. Furthermore, in order to adjust the image quality according to changes in the surrounding environment such as the brightness change outside the vehicle, an environment adjustment value holding unit 236 that holds adjustment values of the image quality of the first video and the second video with respect to the surrounding environment is provided. Have. Here, the image quality setting information storage unit 235 and the environmental adjustment value holding unit 236 are configured by an electrically rewritable nonvolatile memory such as a flash memory or a battery-backed volatile memory.

  For example, an image from the rear monitoring camera 220 connected to the external audio / video input unit 219 may be displayed on the display unit 7. In addition to the rear monitoring camera 220, a video camera, a game machine, and the like may be connected to the external audio / video input unit 219.

  The control unit 200 is based on information detected by the brightness detection unit 221 (for example, a vehicle light switch or optical sensor) or the occupant detection unit 222 (for example, a pressure sensor provided in a driver seat or a passenger seat). It is possible to change settings such as the sound localization position.

  The rear display unit 223 is a display unit provided for the rear seat of the vehicle, and is the same as the image displayed on the display unit 7 via the image output unit 211, or an image for the driver's seat or for the passenger seat One of the images can be displayed.

  The control unit 200 also displays a charge display from the ETC in-vehicle device 224. In addition, the control unit 200 may control the communication unit 225 for wireless connection with a mobile phone or the like, and information related thereto may be displayed.

[Description of Configuration and Operation of Display Device Including Contrast Adjustment Device]
Next, the configuration and operation of a display device including the contrast adjustment device according to the present invention will be described. FIG. 10 is a diagram illustrating a configuration example of a display device 300 including a contrast adjustment device having an A / D conversion unit to which the present invention is applied. The same components as those of the display device shown in FIG. In the present embodiment, the display device 300 will be described as an example applied to a car navigation device that displays TV images, navigation map images, and the like.

  In this embodiment, the description will be made by applying the present invention to a display device that displays separate images (driver seat image and passenger seat pixel) on the same display for two viewing directions. Instead, it may be a display device that displays one image or a display device that displays individual images for two or more viewing directions on the same display. Further, the application range is not limited to in-vehicle use, and any application provided with a display device such as a home TV receiver or a mobile phone is applicable.

  The display device 300 includes a display ASIC (Application Specific Integrated Circuit) 310, a TFT (Thin Film Transistor) type liquid crystal display (corresponding to the display unit 7 in FIG. 6, hereinafter referred to as “TFT”) 7, and a microcomputer 200 (in FIG. 6). And the operation unit 340 (corresponding to the operation unit 215, the touch panel 124, or the remote control 217 in FIG. 6).

  The display ASIC 310 can realize, for example, a so-called multi-view function that can simultaneously display a driver seat image that can be viewed only from the driver seat side and a passenger seat image that can be viewed only from the passenger seat side. Is.

  The display ASIC 310 includes a first A / D converter 311 (provided in various sources (such as the CD / MD playback unit 201) of FIG. 6) and a second A / D converter 312 (also shown in FIG. 6), a switch 313 (corresponding to the distribution circuit 207 in FIG. 6), a synthesis unit 314, and a contrast adjustment unit 315 (first or second image adjustment circuit 208 in FIG. 6). 209, and a rearrangement unit 316 (corresponding to the image output unit 211 in FIG. 6). Note that the display ASIC 310 may not be provided with the rearranging unit 316 but may be provided outside.

  The first A / D converter 311 receives a first analog video signal (for example, an analog NTSC video signal), converts it to a first digital video signal (for example, a digital NTSC signal), and outputs it. To do.

  The second A / D converter 312 receives a second analog video signal (for example, RGB signal indicating a navigation image) and converts it to a second digital video signal (for example, digital RGB signal). Output.

  In addition, when there is an operation instruction for displaying the same image in two viewing directions from the operation unit 340, the image displayed on one of the first A / D conversion unit 311 or the second A / D conversion unit 312 is displayed. A corresponding analog video signal may be input.

  The switch 313 is connected to the second A / D conversion unit 312 and the microcomputer 200, and is also connected to a synthesis unit 314 and a rearrangement unit 316 described later. The switch 313 receives the second digital video signal from the second A / D conversion unit 312 and outputs the signal to the synthesis unit 314 or the rearrangement unit 316. This switching is performed based on a control signal from the microcomputer 200 described later.

  The combining unit 314 is connected to the first A / D conversion unit 311 and the switch 313 and is also connected to a contrast adjustment unit 315 described later. The synthesizer 314 synthesizes the first digital video signal from the first A / D converter 311 and the second digital video signal from the switch 313 and outputs the synthesized signal to the contrast adjuster 315.

  By this synthesis, for example, a navigation image can be displayed on-screen on an NTSC video (or an NTSC video can be displayed on-screen on a navigation image).

  However, when the second digital video signal is not input from the switch 313, the synthesis unit 314 outputs the first digital video signal from the first A / D conversion unit 311 to the contrast adjustment unit 315.

  The contrast adjustment unit 315 is also connected to the rearrangement unit 316 and the microcomputer 200, performs a calculation based on the video signal from the synthesis unit 314 and an adjustment signal from the microcomputer 200 described later, and converts the video signal from the synthesis unit 314. Contrast (whiteness, blackness or brightness, darkness) is adjusted, and the adjusted video signal is output to the rearrangement unit 316.

  The rearrangement unit 316 receives the video signal from the contrast adjustment unit 315 and the video signal from the switch 313, and alternately arranges the pixel values of each video signal for each pixel (or for each of a plurality of pixels) as described above. Instead, it outputs to the TFT 7.

  The rearrangement unit 316 may output the video signal from the switch 313 to the TFT 7 without performing the above-described rearrangement when there is no input of the video signal from the contrast adjustment unit 315, or the switch 313. May be regarded as the video signals from the contrast adjustment unit 315 and the switch 313, and rearranged alternately and output to the TFT 7 as described above. Also, using a specific image (for example, a single color image), the specific image is regarded as a video signal from the contrast adjustment unit 315, and the specific image and the video signal from the switch 313 are alternately arranged and output to the TFT 7 as described above. Alternatively, the video signal from the switch 313 may be arranged in a pixel corresponding to the second video signal and output to the TFT 7.

  Further, the rearrangement unit 316 may output the video signal from the contrast adjustment unit 315 to the TFT 7 without performing the above-described rearrangement when there is no input of the video signal from the switch 313, or adjust the contrast. The video signal from the unit 315 may be regarded as the video signal from the contrast adjustment unit 315 and the switch 313, and may be rearranged alternately and output to the TFT 7 as described above. Further, using the specific image (for example, a single color image), the specific image is regarded as a video signal from the switch 313, and the specific image and the video signal from the contrast adjustment unit 315 are alternately rearranged as described above to the TFT 7. Alternatively, the video signal from the contrast adjustment unit 315 may be arranged in a pixel corresponding to the second video signal and output to the TFT 7.

  Note that a rearrangement control signal for causing the rearrangement unit 316 to perform the above-described control may be output from the microcomputer 200 based on a single image display operation instruction from the operation unit 340, or the occupant detection unit 222 may When it is detected that there is only one occupant, the microcomputer 200 may output a rearrangement control signal that causes the rearrangement unit 316 to perform the above-described control.

  The TFT 7 is connected to the rearrangement unit 316 and displays the video signal from the rearrangement unit 316 on the liquid crystal screen. Note that the front surface of the TFT 7 includes the parallax barrier 108 having a slit having a width of one pixel (or a plurality of pixels) as described above. Since the parallax barrier 108 restricts the emission direction of the display light of each video signal, for example, the first video (for example, NTSC video) indicated by the first video signal is displayed on the passenger seat side, and the driver seat side is displayed. A second video (for example, a navigation image) indicated by the second video signal can be viewed.

  The microcomputer 200 is connected to the operation unit 340, the second A / D conversion unit 312, the switch 313, and the contrast adjustment unit 315. Based on the contrast adjustment instruction of the second video signal from the operation unit 340, the microcomputer 200 contrasts the reference voltage VRH serving as a reference when performing A / D conversion to the second A / D conversion unit 312. Output as an adjustment signal. The microcomputer 200 adjusts the contrast of the second video displayed on the TFT 7 by changing the reference voltage VRH based on the contrast adjustment instruction of the second video signal from the operation unit 340. The microcomputer 200 also outputs a reference voltage serving as a reference during A / D conversion to the first A / D converter 311. In this case, the microcomputer 200 has a constant reference voltage.

  In addition, the microcomputer 200 receives the operation instruction for the same image display, the operation instruction for the composite display of the first video signal and the second video signal, and the operation instruction for the single image display from the operation unit 340. Is a signal for controlling to input an analog video signal corresponding to a video instructed to be displayed on one of the first A / D converter 311 or the second A / D converter 312, or a first digital video A control signal for controlling the switch 313 and a rearrangement control signal for controlling rearrangement of the rearrangement unit 316 are output so that the signal can be combined with the second digital video signal by the synthesis unit 314.

  Here, in this embodiment, the contrast adjustment apparatus according to the present invention is the second A / D converter 312 or the display ASIC 310, or the second A / D converter 312 and the microcomputer 200, or the display ASIC 310 and the microcomputer 200. Corresponding to

  FIG. 11 is a diagram illustrating a relationship between the reference voltage VRH and a second analog video signal (for example, navigation analog RGB video signal) input to the second A / D conversion unit 312. The horizontal axis represents time, and the vertical axis represents the analog voltage value.

  Generally, when A / D conversion is performed, an output digital value is determined based on the reference voltage VRH. That is, as shown in FIG. 11A, the output digital value is determined by the relative ratio when the voltage value of the reference voltage VRH is “255” (when 8-bit output).

For example, if the position of the highest voltage of the analog video signal is A, the voltage value is “1.5V”, and the reference voltage VRH is “2V”, the output digital value X at this position A is
2: 1.5 = 255: X
Ｘ X = (1.5 / 2) × 255 ≒ 191
It becomes.

Here, when the reference voltage VRH is made variable, the output digital value becomes different. For example, as shown in FIG. 11B, when the reference voltage VRH is set to “1.5 V”, the output digital value X1 at the position A is
1.5: 1.5 = 255: X1
１ X1 = (1.5 / 1.5) × 255 = 255
It becomes. When the reference voltage VRH is set to “2.5 V”, the output digital value X2 at the position A is
2.5: 1.5 = 255: X2
Ｘ X2 = (1.5 / 2.5) × 255 ≒ 153
It becomes.

  Therefore, when the reference voltage VRH is variable, the output digital value is also variable. If the output digital value can take a variable value, it is possible to output an image with adjusted contrast indicating whitishness, darkness, or the like.

  FIG. 12 is a diagram showing how the output digital value changes when the reference voltage VRH is changed. The graph on the left shows a graph of an analog video signal with the horizontal axis representing time and the vertical axis representing voltage value. In the diagram on the right side, the horizontal axis represents time, the vertical axis represents the output digital value, and a graph of the digital video signal is shown.

  For example, as shown in FIG. 12B, when the reference voltage VRH is about “1.4 V”, an image is displayed as a standard whitish color. When the reference voltage VRH is higher than that, a darker image is displayed, and when the reference voltage is decreased, a brighter image is displayed (see FIGS. 12A and 12C).

  The contrast is adjusted when the user selects and operates the operation unit 340 (for example, an operation switch or an operation button), and the microcomputer 200 detects the operation and outputs a reference voltage VRH corresponding to the operation.

  Returning to FIG. 10, the contrast-adjusted second video signal (for example, navigation digital RGB signal) is output to the synthesizing unit 314 or the rearranging unit 316 via the switch 313. Thereafter, the rearrangement unit 316 receives the first video signal (for example, NTSC digital video signal) and the second video signal (for example, navigation digital RGB signal), and rearranges the video signals. Each video is displayed on the TFT 7. Therefore, the first video (for example, NTSC video) indicated by the first video signal with the contrast adjusted and the second video (for example, navigation video) indicated by the second video signal with the contrast adjusted are displayed. Displayed on the TFT 7.

  In the present embodiment, since the second A / D conversion unit 312 has already adjusted the contrast of the second video signal, the second A / D conversion unit 312 has the first adjustment between the switch 313 and the rearrangement unit 316 separately from the contrast adjustment unit 315. It is not necessary to provide a contrast adjustment unit for the second video signal. For this reason, the display ASIC 310 can have a simple configuration, and cost reduction can be realized.

  In the above-described embodiment, the example in which the variable reference voltage VRH is output only to the second A / D conversion unit 312 has been described. In addition, as shown in FIG. 13, the reference voltage VRH applied to the first A / D converter 311 as well as the second A / D converter 312 may be output. In this case, the first A / D converter 311 adjusts the contrast in the same manner as the second digital video signal whose contrast is adjusted is output from the second A / D converter 312. The digital video signal is output. Accordingly, since the contrast of the first digital video signal has already been adjusted, it is not necessary to provide the contrast adjustment unit 315 between the synthesis unit 314 and the rearrangement unit 316 as compared with the above-described example. Since it is not necessary to provide the contrast adjustment unit 315, the cost of the display ASIC 310 can be further reduced.

  Further, the same value is not output to the first A / D conversion unit 311 and the second A / D conversion unit 312 with respect to the reference voltage VRH. , The second reference voltage) may be output to each of the conversion units 311 and 312. Each of the conversion units 311 and 312 outputs a digital video signal whose contrast has been adjusted.

  In the above-described embodiment, the switch 313 has been described as an example in which the second digital video signal is switched and output to either the synthesis unit 314 or the rearrangement unit 316. In addition to this, as shown in FIG. 14, the second digital video signal output from the second A / D conversion unit 312 is always output to the rearrangement unit 316, and the second digital video signal is converted into the second digital video signal. The switch 317 can be configured so that the combining unit 314 outputs or does not output. Switching of the output to the synthesis unit 314 is performed based on a control signal from the microcomputer 200. Thus, for example, if the first video is a TV image and the second video is a navigation image, the navigation image is output to the combining unit 314, and the passenger seat (or driver's seat) navigates to the TV image. The image is displayed on the screen, and a navigation image is displayed on the driver's seat side (or passenger seat side).

  Further, in the above-described embodiment, the case where the display ASIC 310 includes the switch 313 has been described. However, the display ASIC 310 does not include the switch 313, and the output of the second A / D conversion unit 312 is input to the rearrangement unit 316. You may be made to do.

  Further, in the above-described embodiment, the first video (for example, NTSC video) is displayed on the TFT 7 as the passenger side video, and the second video (for example, navigation video) is displayed on the TFT 7 as the driver side video. Explained. In addition, various videos may be displayed on each side. For example, a TV image or DVD image received by a TV antenna or the like on the passenger seat side, and a travel regulation image or the like on the driver seat side.

  Further, in the above-described embodiment, the video on the passenger seat side, which is likely to display video that requires fine contrast adjustment, such as NTSC video, TV video, DVD video, etc., is used as the first video signal, and the navigation video. The video on the driver's seat side that is highly likely to display an image that is unlikely to require fine contrast adjustment has been described as the second video signal. In addition, the first video indicated by the first video signal may be displayed on the driver seat side, and the second video indicated by the second video signal may be displayed on the passenger seat side. In this case, this can be realized by controlling pixel rearrangement in the rearrangement unit 316.

  Furthermore, in the above-described embodiment, the case where two videos are displayed has been described, but more videos may be displayed. In this case, it can be realized by performing contrast adjustment on a predetermined number of video signals by the A / D converter.

  Further, in the above-described embodiment, the second A / D conversion unit 312 has been described as outputting a digital value of 8 bits, but of course, the same effect can be obtained with other numbers of bits.

  Furthermore, although the TFT type has been described as an example of the liquid crystal display, various other types such as a STN (Super Twisted Nematic) type and a DSTN (Dual-scan Super Twisted Nematic) type may be used. Further, besides a liquid crystal display, a plasma display or an EL (Electroluminescence) display can be applied. In either case, the same effects as those of the above-described embodiment can be obtained.

  Furthermore, in the above-described embodiment, the case where the contrast adjustment device according to the present invention is applied to a car navigation device has been described. In addition, any device including a display device such as a home TV receiver or a mobile phone can be applied. Even in these cases, the same effect as the above-mentioned example is obtained.

1 is a conceptual diagram of a display device according to the present invention. It is a perspective view which shows the example of mounting of a display apparatus. It is the schematic of the cross-section of a display part. It is the schematic of the structure which looked at the display panel from the front. It is a circuit diagram which shows the outline of a TFT substrate. It is a block diagram which shows the outline of the display apparatus which concerns on this invention. 2 is a block diagram illustrating an outline of an image output unit 211. FIG. 2 is a block diagram illustrating an outline of a control unit 200. FIG. 2 is a block diagram showing an outline of a memory 218. FIG. It is a figure which shows the structural example of a display apparatus. It is a figure which shows the relationship between a reference voltage and an input analog signal. It is a figure which shows the relationship between a reference voltage and an output digital signal. It is a figure which shows the other structural example of a display apparatus. It is a figure which shows the other structural example of a display apparatus.

Explanation of symbols

1: first image source, 2: second image source, 3: first image data, 4: second image data, 5: display control unit, 6: display data, 7: display unit, 8: First display image, 9: Second display image, 10: Observer, 11: Observer, 12: Passenger seat, 13: Driver's seat, 14: Windshield, 15: Operation unit, 16: Speaker, 100: Liquid crystal panel, 101: backlight, 102: polarizing plate, 103: polarizing plate, 104: TFT substrate, 105: liquid crystal layer, 106: color filter substrate, 107: glass substrate, 108: parallax barrier, 109: left side (passenger seat) Side) display pixel, 110: right side (driver's seat) display pixel, 111: display panel drive unit, 112: scanning line drive circuit, 113: data line drive circuit, 114: TFT element, 115 to 118: Data line, 119 121: scanning line, 122: pixel electrode, 123: subpixel, 124: touch panel, 200: control unit, 201: CD / MD playback unit, 202: radio reception unit, 203: TV reception unit, 204: DVD playback unit, 205: HD (Hard Disk) playback unit, 206: Navigation unit, 207: Distribution circuit, 208: First image adjustment circuit, 209: Second image adjustment circuit, 210: Audio adjustment circuit, 211: Image output unit, 212: VICS information reception unit, 213: GPS information reception unit, 214: selector, 215: operation unit, 216: remote control transmission / reception unit, 217: remote control, 218: memory, 219: external audio / video input unit, 220: camera, 221: Brightness detection means, 222: Occupant detection means, 223: Rear display unit, 224: ETC vehicle-mounted device, 225: Communication unit, 22 : First write circuit, 227: second write circuit, 228: VRAM (Video RAM), 229: interface, 230: CPU, 231: program storage unit, 232: data storage unit, 233: first Screen RAM, 234: second screen RAM, 235: image quality setting information storage means, 236: environment adjustment value holding means, 300: display device, 310: display ASIC, 311: first A / D converter, 312 : Second A / D conversion unit, 313: switch, 314: composition unit, 315: contrast adjustment unit, 316: rearrangement unit, 317: switch, 340: operation unit

Claims (6)

A / D conversion means for converting an analog video signal into a digital video signal,
Contrast characterized in that the A / D conversion means outputs the digital video signal, the contrast of which is adjusted based on a reference voltage that is used as a reference when the conversion is input to the A / D conversion means. Adjustment device. The contrast adjustment apparatus according to claim 1,
The contrast adjustment apparatus further comprises control means for making the reference voltage variable. The contrast adjustment apparatus according to claim 1 or 2,
The contrast is characterized in that the A / D conversion means outputs the digital video signal in which the contrast is adjusted by making each digital value constituting the digital video signal different based on the reference voltage. Adjustment device. The contrast adjustment apparatus according to claim 2,
When the control means outputs the first reference voltage to the A / D conversion means, the A / D conversion means outputs the digital video signal with the contrast adjusted as a reference, and the control means When the second reference voltage higher than the first reference voltage is output to the A / D conversion unit, the A / D conversion unit outputs the digital video signal whose contrast is adjusted to be darker than the reference. And when the control means outputs a third reference voltage lower than the first reference voltage to the A / D conversion means, the A / D conversion means adjusts the contrast to be brighter than the reference. A contrast adjusting device, characterized in that said digital video signal is output. In a contrast adjustment method of a contrast adjustment device comprising an A / D conversion means for converting an analog video signal into a digital video signal based on a reference voltage,
A contrast adjustment method, characterized in that the digital video signal whose contrast is adjusted is output from the A / D conversion means by making the reference voltage variable. A display unit capable of displaying individual images for a plurality of viewing directions on the same screen;
A / D conversion means for inputting an analog video signal corresponding to at least one of the plurality of videos and converting it into a digital video signal;
Control means for outputting to the A / D conversion means a reference voltage used as a reference in the conversion,
The display device characterized in that the control means outputs the digital video signal whose contrast is adjusted from the A / D conversion means by making the reference voltage variable.

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