Display control device, display device, and display control method

Abstract

By electrically controlling the switching between two display units, the time required for switching between displaying virtual and real images is reduced. [Solution] The display units 13A and 13B of the display control device 50 perform the following actions in parallel with the display termination operation during the switching period when display by one of the first and second image generation units PGU-1 and PGU-2 is terminated and display by the other image generation unit is started: parallel control, which performs the display start operation in parallel with the display termination operation; interlocking control, which determines the operation timing of the other image generation unit based on the operation timing of the other image generation unit; and overlapping illumination suppression control, which ensures that the on-period of the light source unit (9A or 9B) in one of the image generation units does not overlap in time for at least a portion of the switching period.

Description

Technical Field

[0001] The present invention relates to a display control device, a display device, a display control method, etc. mounted on a vehicle such as an automobile.

Background Art

[0002] Patent Document 1 discloses a head-up display (HUD) device capable of switching between a virtual image and a real image for display.

[0003] In this Patent Document 1, switching between a virtual image and a real image is performed by mechanically changing the mutual positional relationship among a liquid crystal panel (an object to be observed), a two-sided corner reflector array, and a reflecting member (FIG. 12,

[0050] , etc.).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the HUD device of Patent Document 1 above switches between a virtual image and a real image by mechanical control, a considerable amount of time is required for the switching.

[0006] The inventors of the present invention considered performing the switching of images electrically. According to the electrical switching, the switching time can be shortened compared to the mechanical switching. However, as a result of the above consideration, the following matters became clear. (1) For example, assume a case where an electrical switching control is performed in which a first display unit for virtual image display provided with a first backlight and a second display unit for real image display provided with a second backlight are provided, and either the first or second display unit is electrically selected for use. (2) In this case, since leaving unused display units in operation increases current consumption, in order to reduce power consumption, it is conceivable that only the display units being used be set to operation mode, while unused display units, in other words, non-displaying display units, are set to the non-operation mode with the lowest current consumption and kept in standby mode. However, with this configuration, when switching between display units, it is necessary to transition the switched display unit from non-operating mode to operating mode, which results in a considerable delay in switching between the display units being used. (3) When switching between the display units to be used, it is necessary to switch the display unit currently in use to a non-display state, while switching the display unit that has not been used to a display state.

[0007] Here, for example, if a delay occurs during the transition to the non-display state, and this delay causes a delay in turning off the backlight of the display unit during that transition, it is conceivable that the period during which the backlight of the display unit is on during that transition and the period during which the backlight of the display unit is on during the transition to the display state may overlap. In this case, both the real image and the virtual image would be perceived by the viewer, making it impossible to achieve proper image display. (4) In order to suppress the problems described in (3) above, it is preferable to provide a sufficient time interval between the process of switching the display unit currently in use to a hidden state and the process of switching the display unit that has not been used to a displayed state. However, in this case, it is not possible to quickly switch between the display units being used. In other words, while electrical switching control has the potential to complete the switching much faster than before, that potential cannot be fully utilized.

[0008] One of the objectives of the present invention is to reduce the time required for switching between virtual and real images when displaying virtual and real images by electrically controlling the switching of two display units.

[0009] Other objects of the present invention will become apparent to those skilled in the art by referring to the embodiments and best embodiments described below, as well as the accompanying drawings. [Means for solving the problem]

[0010] The following are examples of embodiments of the present invention to facilitate understanding of its outline. (First aspect) In a first embodiment according to the present invention, the display control device has a first image generation unit comprising a first light source unit and a first display unit, and a second image generation unit comprising a second light source unit and a second display unit, and is capable of switching between displaying a first image or a second image by switching between using the first and second image generation units, and controls the switching between the first and second images, wherein the display control device has a control unit, and the control unit terminates the display by either of the first and second image generation units, and terminates the display by the other image generation unit. During the transition period at the start of the switching process, parallel control is implemented to cause the display start operation of the other image generation unit to be performed in parallel with the display end operation of the other image generation unit, and linked control is implemented to determine the operation timing of the other image generation unit based on the operation timing of the other image generation unit. Furthermore, during the switching period, overlapping illumination suppression control is implemented to ensure that the on-period of the light source unit in the other image generation unit does not overlap in time for at least a portion of the period. In the first embodiment, parallel control, interlocking control, and control to suppress overlapping lighting are implemented. Parallel control allows the end-of-display operation of one display unit and the start-of-display operation of the other display unit to be processed in parallel with a time overlap, thereby reducing the time required for switching. Furthermore, because the linked control accurately maintains the relative relationship between the timing of the display termination operation of one display unit and the timing of the display start operation of the other display unit, normal operation is maintained even if a timing discrepancy occurs, enabling stable switching control. Furthermore, by suppressing overlapping illumination, there is always a period of non-overlapping illumination between the illumination period of the first light source and the illumination period of the second light source. During this period, simultaneous on-up of the two light sources is avoided, resulting in lower power consumption. According to the first embodiment, it is possible to switch between virtual and real images at high speed while reliably preventing images from being displayed simultaneously in the first and second display units, and to suppress power consumption. (Second aspect) In a second embodiment dependent on the first embodiment, the control for ending the display by either the first or second image generation unit, and the control for starting the display by the other image generation unit, are sequence controls that sequentially advance the control of each stage in a plurality of stages according to a predetermined order or procedure, and in the parallel control, the sequence is completed when all of the plurality of stages are executed, but if it is stopped at an intermediate stage, the display unit of either the first image generation unit and the display unit of the other image generation unit may be in a low-power consumption mode in which the current consumption is set lower than during normal operation. In the second embodiment, sequence control is employed as the control by the display control device, and in this sequence control, if the process is stopped (interrupted) at an intermediate stage among multiple stages, the display unit enters a low power consumption mode (e.g., standby mode) to suppress power consumption. Therefore, according to the second embodiment, while achieving low power consumption of the display unit, when the operation of two image generation units proceeds in parallel by parallel control, it becomes possible to temporarily stop the operation and resume it after waiting for an appropriate timing, thereby enabling advanced display switching control. (Third aspect) In a third embodiment dependent on the first embodiment, the control unit may, in the interlocking control, set a predetermined time difference between the off timing of the display unit of either of the image generation units and the on timing of the display unit of the other image generation unit, thereby preventing the temporal overlap between the on period of the light source unit of either of the image generation units and the on period of the light source unit of the other image generation unit in the overlapping illumination suppression control. According to the third embodiment, a predetermined off period can be provided between the illumination period of one display unit and the illumination period of the other display unit, thereby reliably preventing simultaneous on-up of each display unit. Therefore, it becomes possible to switch between virtual and real images at high speed while reliably preventing images from being displayed simultaneously on each display unit.

[0011] In a fourth embodiment dependent on the first embodiment, the vehicle display control device is mounted on a vehicle and capable of switching between displaying a virtual image or a real image as an image to a viewer who is a passenger in the vehicle, and the first display unit is a display unit for displaying a virtual image equipped with a first backlight, and the second display unit is a display unit for displaying a real image equipped with a second backlight, and the control unit is capable of switching between using the first and second display units, the activation of the first and second display units is carried out by an activation sequence, and the termination of the display of the first and second display units is carried out by an termination sequence. Each of the startup and shutdown sequences is a control that sequentially advances each stage of control according to a predetermined order or procedure, the startup sequence includes a first startup stage that releases the reset of the first and second display units, a second startup stage that starts inputting video signals to the first and second display units, a third startup stage that inputs a display on command to the first and second display units to turn on the display, and a fourth startup stage that turns on the first and second backlights of the first and second display units, and the shutdown sequence includes the first and second display units The startup and shutdown sequences include a first termination stage in which the first and second backlights are turned off, a second termination stage in which a display off command is input to the first and second display units to turn off the display, a third termination stage in which the input of video signals to the first and second display units is terminated, and a fourth termination stage in which the first and second display units are reset. In each startup and shutdown sequence, the sequence is completed when all stages are executed, but if the sequence is stopped at an intermediate stage, the first and second display units are set to low power consumption, with current consumption lower than during normal operation. In power mode, the control unit of the display control device, when executing the first startup step for either the first or second display unit by releasing the reset, executes a first linked control to start the first startup step for the other display unit in parallel with the start timing of the startup step for the other display unit, and when executing the second startup step by starting the input of a video signal for either the first or second display unit, executes a first linked control to start the input of a video signal for the other display unit in parallel with the start timing of the input of a video signal for the other display unit. When the input of the video signal ends, a second linked control is performed to start the second startup stage in parallel, and then, in only one of the display units, the third startup stage is performed by inputting the display on command, and the fourth startup stage is performed by lighting either the first or second backlight, thereby starting the display of the video in one of the display units, and then, in the display unit that is displaying the video, the first to fourth termination stages are performed to end the display,During the end period of the display, a third interlocking control may be performed, which involves simultaneously executing the third startup phase, triggered by the input of the display-on command, and the fourth startup phase, which involves illuminating the other of the first and second backlights, in either the first or second display unit, and ensuring that the illumination period of one of the first and second backlights does not overlap with the illumination period of the other of the first and second backlights.

[0012] In the fourth embodiment, in order to shorten the time required for switching between the first and second display units, the operations of the first and second display units are performed in parallel with time overlap. If the operation of each display unit is to be performed in parallel, allowing for temporal overlap, the current consumption will inevitably increase because display units that are not currently being used for image display will be operating. However, in this embodiment, while the startup and shutdown sequences for each display unit are completed when all steps are executed, if the sequence is stopped at an intermediate step, the first and second display units are configured to operate in a low-power mode with a lower current consumption than during normal operation. Therefore, even if some sequence stages of the display unit, which is not used for image display at that point, are executed, the current consumption will be lower than the normal operating current, resulting in only a small increase in current consumption, which does not pose a particular problem. Furthermore, in this embodiment, instead of the conventional "individual control" which controls the operation of each display unit individually, "interlocking control" is implemented. "Interlocking control" is a control method in which the operating timing of one of the first or second display units is automatically determined in conjunction with a reference operating timing of the other display unit. If the operation of the first and second display units is controlled individually, for example, if a delay occurs in the operation of one of the display units, the other display unit will continue to operate without taking that delay into account. This can lead to a lack of coordination between the operations of each display unit, potentially resulting in problems such as both display units displaying images simultaneously.

[0013] By implementing linked control, even if the operating timing of one display unit fluctuates, that fluctuation will also occur in the operating timing of the other display unit. As a result, the relative relationship of the operating timings between each display unit, in other words, the temporal consistency, is always maintained, and the aforementioned problems can be reliably suppressed. The interlocking control implemented in this embodiment includes first, second, and third interlocking control. The "first interlocking control" is an interlocking control that, when performing the first startup step to release the reset of one of the display units and make it operational, performs the first startup step for the other display unit in conjunction with that timing (for example, synchronously and simultaneously, or with a predetermined time delay from that timing), releasing the reset and making it operational. When the reset of one of the display units is released, the reset of the other display unit is also released, allowing it to operate. This makes it possible to perform the operations of each display unit in parallel, with a time overlap. The "second linked control" is a linked control that, when the input of a video signal is started to either display unit to execute the second startup stage, is also linked to the timing of the start of the input of the video signal on the other display unit, or the timing of the end of the input of the video signal on the other display unit, to start the second startup stage in parallel. When the second interlocking control is implemented, if a video signal is input to either display unit, a video signal is also input to the other display unit in conjunction with it, thereby completing the first and second startup stages that are prerequisites for displaying an image for the other display unit. In other words, this second interlocking control allows the other display unit to be put into a standby state awaiting the third and fourth startup stages (input of a display-on command, backlight illumination). The "first and second interlocking control" described above is a control in which the "activation period" of one of the display units and the "activation period" of the other display unit overlap temporally and proceed in parallel. Next, the "third interlocking control" is implemented. This "third interlocking control" is a control in which the "end period" of one of the display units and the "activation period" of the other display unit overlap temporally and proceed in parallel. In other words, in the "third interlocking control", when the first to fourth end stages are implemented to end the display in one of the display units that is displaying an image, during the end period of that display, the third activation stage by input of the display on command in the other of the first and second display units and the fourth activation stage of lighting one of the first and second backlights are implemented in parallel. At this time, interlocking control is executed so that the lighting period of one of the first and second backlights does not overlap with the lighting period of the other of the first and second backlights. As described above, in the interlocking control, the operation timing of one of the display units and the operation timing of the other display unit can be interlocked, and the mutual relationship (consistency) of each timing can be determined in advance. By utilizing this advantage, it is possible to surely avoid the simultaneous lighting of the first and second backlights (each display simultaneously displaying an image). Also, in the "third interlocking control", as described above, since the simultaneous lighting of the first and second backlights can be surely avoided, the margin period for avoiding simultaneous lighting can be set to a minimum. In other words, in the "third interlocking control", the temporal margin for avoiding simultaneous lighting may be minimal, and in this respect as well, the switching speed of the display units is increased. Therefore, according to this aspect, it is possible to quickly switch the image display of a plurality of display units while surely suppressing the simultaneous display of a plurality of images by electrical switching control.

[0014] In a fifth embodiment dependent on the fourth embodiment, the display control device may, in the second interlocking control, execute the second startup step in the other of the first or second display unit in conjunction with the timing of the start of video signal input in either the first or second display unit to start input of a video signal, and in the third interlocking control, execute the first termination step in either the first or second display unit to turn off either the first or second backlight at the first timing, and then, in the second timing after a predetermined first delay time has elapsed from the first timing, execute the second termination step to turn the display off, and in the other of the first or second display unit, execute the third startup step at the first timing to turn the display on, and execute the fourth startup step at the second timing to turn on either the first or second backlight.

[0015] The fifth aspect shows a preferred control of the third interlocking control in the second interlocking control, where the second startup step is performed on the other of the first or second display unit in conjunction with the "input start timing" of the video signal on either the first or second display unit to start inputting the video signal. The termination sequence is executed in either the display unit. First, the first termination stage is executed, and at the "first timing," either the first or second backlight is turned off. Next, at the "second timing," which is the predetermined "first delay time" that has elapsed since the first timing, the second termination stage is executed to turn off the display. Meanwhile, in the other display unit, the third and fourth startup sequences are executed in parallel with the termination sequence of the other display unit. At this time, the third startup phase is executed at the "first timing" described above to turn the display on. Furthermore, at the "second timing" described above, the fourth startup stage is executed to illuminate either the first or second backlight. Since the backlight is turned off at the "first timing" on either display unit, the possibility of both backlights being on simultaneously is eliminated. Therefore, at this "first timing," or in other words, at the shortest possible timing without any redundant time buffer, the other display unit performs the third startup stage and turns on the display. This reduces the time required to switch displays. Next, in either display unit, the second termination stage is performed at the "second timing," which is the time after the "first delay period" has elapsed from the "first timing," and the display is turned off. At this time, in the other display unit, the fourth startup stage is performed at the second timing described above, and the backlight is turned on. This linked control ensures that the backlight on one display unit turns off at a first timing, and then, after a first delay period has elapsed, the backlight on the other display unit turns off at a second timing. There is always a "first delay period" between the off-times of each backlight, thus reliably preventing both backlights from being on simultaneously. Consequently, the inconvenience of both display units operating and displaying images at the same time does not occur. Thus, according to the second embodiment, time is reduced by minimizing the time margin, and a third interlocking control is implemented so that a predetermined delay time (first delay time) is provided between the off timings of the two backlights. Therefore, the shutdown process for one display unit and the startup process for the other can be performed in parallel without any wasted time, and simultaneous illumination of both backlights can be reliably prevented.

[0016] In a sixth embodiment dependent on the fourth embodiment, the display control device, in the second interlocking control, in conjunction with the timing at which the input of the video signal to either the first or second display unit ends, executes the second startup step in the other of the first or second display unit to start inputting the video signal, and in the third interlocking control, executes the first termination step in either the first or second display unit to turn off either the first or second backlight at the first timing, and subsequently, after a predetermined first delay time has elapsed from the first timing, At timing 2, the second and third termination stages are executed to turn the display off and terminate the input of the video signal. At timing 2, the second startup stage is executed in either the first or second display unit to start the input of the video signal. At timing 3, after a predetermined second delay time has elapsed from timing 2, the third startup stage is executed to turn the display on. At timing 4, after a predetermined third delay time has elapsed from timing 3, the fourth startup stage is executed to light up either the first or second backlight.

[0017] The sixth aspect describes a preferred control of the third interlocking control in which, in the second interlocking control, the second startup step is executed on the other of the first or second display unit in conjunction with the "end timing" of the video signal on either the first or second display unit to start inputting the video signal.

[0018] In the sixth embodiment, the same interlocking control as in the second embodiment described above is implemented. However, in this embodiment, the timing of the input of the video signal to the other display unit is delayed compared to the second embodiment, which reduces the time margin and makes it difficult to control the process up to the point of backlight illumination. In other words, it is necessary to take measures to address the case where the timing of the video signal in the other display unit is delayed for any reason. In the third embodiment, first, similar to the second embodiment, the first termination step is performed in either the display unit and either the first or second backlight is turned off at the "first timing". Next, at the "second timing," which is the time after a predetermined "first delay period" has elapsed since the "first timing," the second and third termination stages are executed simultaneously to turn off the display and terminate the input of the video signal. In the second embodiment described above, the video signal was input before the second timing, and the only step performed at the second timing was the second termination step, which turned the display off. In the third embodiment, the input of the video signal also ends at the second timing. In this respect, it differs from the second embodiment. Furthermore, in either the other display unit, the input of the video signal is initiated in conjunction with the "second timing." In other words, the switching of the video signal is performed at the "second timing." Next, at the "third timing," which is the result of a predetermined "second delay time" elapsed from the "second timing," the third startup stage is executed to turn on the display. Then, at the "fourth timing," which is the result of a predetermined "third delay time" elapsed from the "third timing," the fourth startup stage is executed to turn on either the first or second backlight. In the above-described interlocking control, a "first delay time," a "second delay time," and a "third delay time" are intervened between the time the backlight of one of the display units is turned off at the first timing and the time the backlight of the other display unit is turned on. In the second embodiment described above, there was only the first delay time, but in this embodiment, taking into consideration unforeseen circumstances such as delays that occur when switching video signals, a second and third delay time are also provided as a precaution to prevent simultaneous turning on of both backlights. As a result, in this embodiment, the termination of the video signal to one display unit and the start of the video signal to the other display unit can be performed at the same time, the termination process for one display unit and the startup process for the other can be performed in parallel without any wasted time, and simultaneous illumination of both backlights can be reliably prevented.

[0019] In a seventh embodiment dependent on the sixth embodiment, when the display control device inputs a video signal for each of the first and second display units, it may supply the respective video signals via a common signal line and control the path of a selector connected to the common signal line with a selection signal, thereby determining which of the first and second display units to input the video signal supplied via the common signal line.

[0020] According to the seventh embodiment, the signal lines supplying the video signal to the first and second display units can be made common, and the configuration for inputting the video signal to each display unit can be simplified. The present invention is not limited to the above embodiments, and various modifications and applications are possible. The eighth to twelfth aspects described below are examples of modifications and applications. (Eighth aspect) In an eighth embodiment dependent on the first embodiment, the control unit may, in the control of suppressing overlapping illumination, prohibit the temporal overlap between the on-period of one of the light sources and the on-period of the other light source, and may also perform a full-black screen display process in which a black video signal is supplied to the display unit of the other image generation unit to display a full-black screen during the period from the end of the on-period of the light source in the one of the image generation units until the start of the on-period of the light source in the other image generation unit. In the eighth aspect, the on periods of the two light sources are prohibited from overlapping in time, but during the non-overlapping periods (off periods), each of the two display units is capable of displaying an image. In other words, the on periods of the two display units (periods during which an image can be displayed) overlap in time. Therefore, for example, it is conceivable that external light (such as sunlight or light from lighting fixtures) entering the casing of the display device could become stray light, causing the screen of the display unit, which is normally not visible, to appear slightly brighter. In this case, the viewer may perceive two separate display units, making it difficult to see. To suppress this inconvenience, in the eighth aspect, a full-black screen display process is implemented. In other words, by supplying a black video signal to the display unit in which the display operation has started, making the screen (image display area) of that display unit a full-black screen, and using that full-black screen as a mask to prevent the emission of unwanted light, the above inconvenience can be suppressed. (Ninth aspect) In a ninth embodiment dependent on the first embodiment, the control unit may, in the control of suppressing overlapping illumination, temporally overlap the on-period of the light source unit in either of the image generation units with the on-period of the light source unit in either of the image generation units for a portion of the switching period, and perform a full-black screen display process to display a full-black screen by supplying a black video signal to the display unit in either of the image generation units for at least a portion of the switching period. In the ninth embodiment, it is permissible for the ON periods of the two light sources to partially overlap during the switching period. During the switching period, both display units are capable of displaying images, and the periods when the light sources are on also overlap. Therefore, it is not impossible that, for example, an image might appear on the screen of a display unit that is normally not supposed to be displayed. In this case, the viewer may perceive both display units visually, making it difficult to see. Therefore, in this embodiment, a full-black screen display process is performed on the display unit in which the display operation has started. In other words, by supplying a black video signal for at least a portion of the switching period, the screen (image display area) of the display unit is made to display a full-black screen, and by using this full-black screen as a mask to prevent the emission of unwanted light, the above-mentioned problems can be suppressed. In a tenth embodiment dependent on the ninth embodiment, the control unit may, in parallel with the display of the other image generation unit, perform a video display for display termination on the display unit of one of the image generation units, and in conjunction with the termination of the video display for display termination, cancel the all-black screen display on the other display to return to a normal image display. In the tenth embodiment, the ninth embodiment (an embodiment that allows for a partial overlap of the ON periods of the two light sources during the switching period, and performs a full black screen display process on the display unit where the image display start process is being performed) is improved to achieve a display switching that is easier to see and understand. In other words, in this embodiment, the display unit where the display ends implements, for example, a "video display for display termination" (a continuous image display in time, which can also be called an animation display) that can notify the viewer that the image display has ended. In the eighth embodiment described above, after the image display of one of the two display units has finished, the image display of the other display unit starts after a predetermined period of time. As a result, during the display switching period, there is a blank period in which no image is displayed on either of the two display units. In contrast, in this embodiment, a moving image (a series of images in time) suitable for notifying the end of the image display is displayed on the display unit where the image display ends, thereby achieving a more natural visual transition for the viewer. Furthermore, in this embodiment, the all-black screen display is canceled and the display returns to normal image display in conjunction with the end of the video display used to end the display. As a result, when the video display ends on one display unit, the normal display can start on another display unit without delay, for example, and in this respect as well, a more natural and accurate switching is achieved. Furthermore, by actually using the display device, viewers can empirically learn that when the video marking the end of the display finishes playing on one display unit, the image display begins on the other display unit. Since the duration of the video marking the end of the display is fixed, viewers can predict how long it will take for the image display on the other display unit to begin, thus increasing their sense of security. As a result, a more natural, accurate, and reassuring display switching experience with superior visual appeal is achieved. In an eleventh embodiment dependent on the tenth embodiment, the video display for ending the display may be an image display that slides out the displayed image, or an image display that fades out the displayed image, or an image display that zooms out the displayed image. In the eleventh aspect, a preferred example of a video display for ending the display is shown. Slideout is an image erasure method that moves the position of the displayed image on the screen, gradually erasing it over time. Fade-out is an image removal method that gradually reduces the brightness (luminance) of an image displayed on the screen over time, thereby gradually making the image disappear. Zooming out is an image removal method that gradually reduces the size of the displayed image on the screen over time, thereby gradually erasing the image. By using these methods, the display of images can be terminated without causing discomfort to the viewer. In a twelfth embodiment dependent on the ninth embodiment, the control unit may perform a dimming process to reduce the illumination intensity of the light source in the other image generation unit to a lower level than the normal illumination intensity for at least a portion of the period during which the all-black screen display is performed in the display unit of the other image generation unit. In the twelfth embodiment, the image generation unit that initiates the display performs a display of a completely black screen, and the light source unit performs a process to reduce the illumination intensity (luminescence intensity) of the light source compared to the normal state for at least a portion of the period during which the completely black screen is displayed. As explained earlier, the all-black screen display functions as a mask to prevent the emission of unnecessary light, and at least during the all-black screen period, the light source does not need to emit light. However, since it takes time to turn the light source back on if it is turned off, dimming is performed in this embodiment. This further reduces (suppresses) power consumption.

[0021] In the 13th embodiment, the display device is mounted on a vehicle and is capable of switching between displaying a virtual image or a real image as an image to a viewer who is a passenger in the vehicle, and includes a first display unit for displaying a virtual image, which has a first backlight, a second display unit for displaying a real image, which has a second backlight, and a display control device according to any one of the first to 12 embodiments described above.

[0022] According to the 13th embodiment, a display device can be realized that can switch between virtual and real images at high speed while reliably preventing images from being displayed simultaneously in each display unit. Furthermore, power consumption can be effectively suppressed.

[0023] In a 14th embodiment dependent on the 13th embodiment, the display device may be a head-up display device having an emission window, which emits display light generated by the first or second display unit from the emission window, thereby allowing the viewer to see a virtual image and a real image which are images represented by the display light.

[0024] According to the 14th embodiment, a head-up display device can be realized that can switch between virtual and real images at high speed while reliably preventing images from being displayed simultaneously in each display unit. Furthermore, power consumption can be effectively suppressed.

[0025] In a 15th embodiment, a display control method for controlling the switching of a first and second image in a display device having a first image generation unit comprising a first light source unit and a first display unit, and a second image generation unit comprising a second light source unit and a second display unit, wherein the first and second image generation units can be switched to display either a first image or a second image, the method includes parallel control, in which a display start operation is performed in the other image generation unit in parallel with the display end operation in the first image generation unit, and interlocking control, in which the operation timing of the other image generation unit is determined starting from the operation timing of the first image generation unit, and overlapping illumination suppression control, in which, in the switching period, the on-period of the light source unit in the first image generation unit and the on-period of the light source unit in the other image generation unit do not overlap in time for at least a portion of the period.

[0026] According to the 15th aspect, a display control method can be realized that reliably prevents images from being displayed simultaneously in the first and second display units, while enabling high-speed switching between virtual and real images and suppressing power consumption.

[0027] Those skilled in the art will readily understand that the embodiments of the present invention illustrated can be further modified without departing from the spirit of the invention. [Brief explanation of the drawing]

[0028] [Figure 1] Figures 1(A) to 1(D) show outlines of the first to fifth embodiments of the present invention. [Figure 2] Figure 2 shows an example of the configuration of a head-up display device as a display device according to an embodiment of the present invention. [Figure 3] Figure 3 shows an example of virtual image display and an example of real image display using a head-up display. [Figure 4] Figures 4(A) and 4(B) show examples of lens configurations in the first and second display units, respectively. [Figure 5] Figure 5 shows an example of the configuration of the display control device according to the first embodiment, and an example of display control by the display control device. [Figure 6] Figure 6 is a timing chart showing an example of linked control by the display control device in Figure 5. [Figure 7] Figure 7 is a timing chart of a comparative example with respect to Figure 6. [Figure 8] Figure 8 is a flowchart showing the main control procedures corresponding to the interlocking control shown in Figure 6. [Figure 9] Figure 9 shows another example of the configuration of the display control device according to the second embodiment, and another example of display control by the display control device. [Figure 10] Figure 10 is a timing chart showing an example of linked control by a display control device in the example shown in Figure 9. [Figure 11]Figure 11 is a timing chart of a comparative example with respect to Figure 10. [Figure 12] Figure 12 is a flowchart showing the main control procedures corresponding to the interlocking control shown in Figure 9. [Figure 13] Figure 13 is a timing chart showing an example of interlocking control by a display control device according to the third embodiment. [Figure 14] Figure 14 is a flowchart showing the main control procedure of the third embodiment (Figure 13). [Figure 15] Figure 15 is a timing chart showing an example of interlocking control by the display control device according to the fourth embodiment. [Figure 16] Figure 16 is a flowchart showing the main control procedure of the fourth embodiment (Figure 15). [Figure 17] Figure 17 is a timing chart showing an example of interlocking control by the display control device according to the fifth embodiment. [Figure 18] Figure 18 is a flowchart showing the main control procedure of the fifth embodiment (Figure 17). [Modes for carrying out the invention]

[0029] The best embodiments described below are used to facilitate understanding of the present invention. Therefore, those skilled in the art should note that the present invention is not unduly limited by the embodiments described below. (Summary of each embodiment) First, the outlines of the first to fifth embodiments of the present invention will be described with reference to Figure 1. Figures 1(A) to 1(D) are diagrams illustrating the outlines of the first to fifth embodiments of the present invention. 1. Overview of the display device configuration Figure 1(A) shows an example of how the display device of the present invention (equipped with a display control device) is used, and Figure 1(B) shows an example of the basic (principal) configuration of the display device of the present invention. In the example shown in Figure 1(A), the head-up display (HUD) device 100 is mounted on the vehicle 1. The HUD device 100 comprises a first image generation unit PGU-1 and a second image generation unit PGU-2. When the first image generation unit PGU-1 is used, the display light travels through the optical path L1, and a portion of the display light is reflected by the windshield WS on the vehicle 1 and incident on the eye (viewpoint) EY of the observer DR, who is the occupant (driver, etc.). As a result, the real image RV is displayed. Similarly, when the second image generation unit PGU-2 is used, the display light travels through the optical path L2, as a result, the virtual image V is displayed. By selecting which of the first and second image generation units PGU-1 and PGU-2 to use, it is possible to switch between displaying the real image RV and the virtual image V. As shown in Figure 1(B), the first control unit 13A provided in the display control device 50 controls the operation of the first image generation unit PGU-1, and the second control unit 13B controls the operation of the second image generation unit PGU-2. The first image generation unit PGU-1 comprises a first light source unit (first backlight) 9A and a first liquid crystal display unit (first liquid crystal panel) 126A. The second image generation unit PGU-2 comprises a second light source unit (second backlight) 9B and a second liquid crystal display unit (second liquid crystal panel) 126B. The first control unit 13A supplies a video signal (in other words, an image signal) VID1 and a control signal TFTC1 to the first liquid crystal display unit 126A, and also supplies a control signal BL1 to the first light source unit (first backlight) 9A. The second control unit 13B supplies the video signal (in other words, image signal) VID2 and the control signal TFTC2 to the second liquid crystal display unit 126B, and also supplies the control signal BL2 to the second light source unit (second backlight) 9B. 2. Overview of the First Embodiment Refer to Figure 1(C). The first and second control units 13A and 13B of the display control device 50 perform predetermined startup sequences and predetermined shutdown sequences when starting up and shutting down the first and second image generation units PGU-1 and PGU-2. In each startup and shutdown sequence, the sequence is completed when all stages are executed. However, if the sequence is stopped at an intermediate stage, the first and second liquid crystal display units 126A and 126B are designed to reduce current consumption by entering a low-power mode in which current consumption is set lower than during normal operation. The "First TFT-RES" and "Second TFT-RES" indicated on the left side of Figure 1(C) are control signals that release the reset of the first and second image generation units PGU-1 and PGU-2, respectively. In the first embodiment, when the first TFT-RES reaches an active level (H level) at time t2, the second TFT-RES also reaches an active level in conjunction with it (specifically, in synchronization), thereby enabling the control of the second image generation unit PGU-2 in parallel with the control of the first image generation unit PGU-1. In other words, in Figure 1(C), "interlocking control" and "parallel control" are being implemented. With respect to the first image generation unit PGU-1, at time t3, a video signal (image signal) VID1 is supplied to the first liquid crystal display unit 126A. After a predetermined time, the first liquid crystal display unit 126A enters a display-on state (in other words, a display-ready state), and after a predetermined time, the first backlight 9A is turned on. Meanwhile, with respect to the second image generation unit PGU-2, at time t3, a video signal (image signal) VID2 is supplied to the second liquid crystal display unit 126B. In Figure 1(C), the supply method of the video signal (image signal) VID2 is shown with a dashed line, but this relates to the third embodiment, so its explanation is omitted here. Subsequently, at time t6, the second liquid crystal display unit 126B becomes display-on (in other words, ready to display), and the second backlight 9B turns on after a predetermined time ΔT2 has elapsed. Since the second backlight 9B turns on after a predetermined time ΔT2 has elapsed since the first backlight 9A was turned off, the turning on of each backlight 9A and 9B does not overlap in time, and therefore the increase in power consumption caused by both backlights 9A and 9B turning on simultaneously is suppressed. In other words, "overlapping illumination suppression control" is implemented to prevent the simultaneous turning on of the two backlights, thereby suppressing power consumption. 3. Overview of the second embodiment The second embodiment is not shown in Figure 1 for convenience, but its details are shown in Figure 9. As shown in Figure 9, in the second embodiment, a selector is used to share the supply lines for the first and second video signals (image signals) VID1 and VID2, thereby reducing the number of signal lines. 4. Overview of the Third Embodiment In the third embodiment, the supply mode shown by the dashed line (a mode in which a black video signal is supplied) is adopted for the supply of the video signal (image signal) VID2 in Figure 1(C). For example, it is conceivable that external light (such as sunlight or light from lighting fixtures) entering the housing of the display device could become stray light, causing the screen of the second liquid crystal display unit 126B, which is normally not displayed, to become slightly brighter. In this case, the viewer DR would perceive both the two liquid crystal display units 126A and 126B visually, making it difficult to see. As a countermeasure, in the third embodiment, a black video signal is supplied in the video signal (image signal) VID2 at least during the period from time t6 to t7 (the period ΔT2), thereby causing the screen (image display area) of the second liquid crystal display unit 126B to display a completely black screen. This all-black display screen acts as a mask to block the emission of unwanted light, thereby mitigating the aforementioned problems. 5. Overview of the Fourth Embodiment In the fourth embodiment, as shown in Figure 1(D), it is permissible for the ON periods of the two light sources to partially overlap during the switching period (see period TQ from time t37 to t38 in Figure 1(C)). Furthermore, a full black screen display process is performed on the second liquid crystal display unit 126B of the second image generation unit PGU-2 when image display begins (see the switching period (TS+TQ period) from time t35 to t38 in Figure 1(D)). However, the full black screen display may be performed for at least a portion of the switching period. In this case, it is preferable to use a full black screen display in particular during the period when the backlight on periods of each display unit overlap (period TQ from time t37 to t38) in order to reliably prevent the display of unnecessary images on the second liquid crystal display unit 126B. Furthermore, in the first liquid crystal display unit 126A that terminates the display, for example, during the switching period (the period from time t35 to t38 in Figure 1(D)), a "video display for display termination" (a continuous image display in time, which can also be called an animation display) is implemented to notify the viewer that the image display has ended. This enables a smooth and natural image deletion without any abruptness. In Figure 1(D), the video signal (image signal) VID1 during the video display period is marked with diagonal lines. Examples of the types of video display erasures include slide-out (symbol d-1), fade-out (symbol d-2), and zoom-out (symbol d-3), as shown on the left side of Figure 1(D). Slideout, in the example shown in Figure 1(D), is a technique that gradually erases image 62a by moving the position of the displayed image 62a over time on the virtual display surface VS (see Figure 2) where the virtual image V is displayed. In the example shown in Figure 1(D), fade-out is a technique that gradually erases image 62a by decreasing the brightness of the displayed image 62b over time on the virtual display surface VS (see Figure 2) where the virtual image V is displayed. Zooming out, in the example shown in Figure 1(D), is a technique that gradually erases the image 62c by decreasing its size over time on the virtual display surface VS (see Figure 2) where the virtual image V is displayed. Furthermore, in the example shown in Figure 1(D), the all-black screen display is canceled and the image is displayed normally in conjunction with the end of the video display used to end the display (time t38 in Figure 1(C)). This allows the normal display to start on another display unit without delay when the video display ends on one display unit, resulting in a more natural transition. Furthermore, by actually using the HUD device 100, the viewer DR can empirically learn that when the video indicating the end of the display finishes being displayed on one display unit (the first liquid crystal display unit 126A in Figure 1(D)), the image display starts on another display unit (the second liquid crystal display unit 126B in Figure 1(D)). Here, since the time from the start to the end of the video used to end the display (the period from time t35 to t38 in Figure 1(D)) is fixed, the viewer (DR) can predict how long it will take before the image display on the other display unit starts, thus increasing their sense of security. Therefore, a more natural, reassuring, and visually superior display switching is achieved. 6. Overview of the Fifth Embodiment In the fifth embodiment, the configuration shown by the dashed line is adopted for turning on the second light source (backlight) 9B in Figure 1(D). In the fifth embodiment, the image generation unit that initiates the display (the second image generation unit PGU-2 in the example of Figure 1) performs a full black screen display on the second display unit 126B, and the second light source unit (backlight) 9B performs a process to reduce the illumination intensity (luminescence intensity) of the backlight compared to the normal state for at least a portion of the period during which the full black screen is displayed (in Figure 1(D), the period TQ from time t37 to t38 when the two backlights are turned on at the same time). In Figure 1(D), shading is applied during the period when dimming is performed while the backlight is on. The all-black screen display functions as a mask to prevent the emission of unnecessary light. At least during the all-black screen period, the light source does not need to emit light. However, since it takes time to turn the light source back on if it is turned off, dimming is performed. This further reduces (suppresses) power consumption. The above is an overview of each of the first to fifth embodiments. The embodiments will be described in detail below with reference to Figures 2 to 8.

[0030] (First embodiment) Refer to Figure 2. Figure 2 is a diagram showing an example of the configuration of a head-up display device as a display device according to an embodiment of the present invention.

[0031] The head-up display (HUD) device 100 mounted on the vehicle 1 includes a first image generation unit PGU-1 (PGU: Picture Generation Unit), a second image generation unit PGU-2, and an optical system 2, all located inside a housing 19 equipped with an output window 17.

[0032] The first image generation unit PGU-1 comprises a first display unit 11A and a first control unit (display control unit) 13A. The second image generation unit PGU-2 comprises a second display unit 11B and a second control unit (display control unit) 13B.

[0033] The first display unit 11A comprises a first light source unit, in other words, a first backlight 9A, and a first liquid crystal display unit (first liquid crystal panel) 126A formed on a circuit board 130A.

[0034] The second display unit 11B comprises a second light source unit 9B, in other words, a second backlight 9B, and a second liquid crystal display unit (second liquid crystal panel) 126B formed on the circuit board 130B.

[0035] The first light source unit (first backlight) 9A comprises a circuit board 12A for the light source and a plurality of light-emitting elements (LEDs (Light Emitted Diodes), etc.) 122A formed on the circuit board 12A for the light source. The second light source unit (second backlight) 9B comprises a circuit board 12B for the light source and a plurality of light-emitting elements (LEDs, etc.) 122B formed on the circuit board 12B for the light source. Examples of lens configurations in the first and second light source units 9A and 9B will be described later.

[0036] The first control unit 13A controls the operation of the first light source unit (first backlight) 9A and the first liquid crystal display unit (liquid crystal panel) 126A in the first display unit 11A using the control signal SG1. The second control unit 13B controls the operation of the first light source unit (first backlight) 9B and the second liquid crystal display unit 126B in the second display unit 11B using the control signal SG2.

[0037] The first and second control units 13A and 13B constitute a display control device (not shown in Figure 2, reference numeral 50 in Figure 5).

[0038] Furthermore, the first and second control units 13A and 13B can communicate with each other using control signals SG3, etc., and perform the interlocking control described later.

[0039] The optical system 2 includes a first curved mirror (in other words, a curved lens with light reflectivity and transmission) 22 having light reflectivity and transmission properties, and a second curved mirror (such as a concave mirror) 24 that reflects light. Furthermore, a windshield WS, which is the projection target of the vehicle 1, may also be included as a component of the optical system 2.

[0040] In the figure, the optical path L1 shown by the solid line represents a typical optical path (main path along the optical axis) of the display light of the image generated by the first display unit 11A included in the first image generation unit PGU-1.

[0041] The display light generated by the first display unit 11A is emitted through the emission window 17 of the HUD device 100 and enters the eye (viewpoint) EY of the viewer DR, who is an occupant (driver, etc.) of the vehicle 1, located at the eye box EB, via the optical path L1.

[0042] As a result, the image generated by the first display unit 11A is perceived as a real image RV on the virtual real image display surface RS.

[0043] In the figure, the dashed line L2 indicates a typical optical path (main path along the optical axis) of the display light of the image generated by the second display unit 11B included in the second image generation unit PGU-2.

[0044] The display light generated by the second display unit 11B is emitted through the emission window 17 of the HUD device 100 and enters the eye (viewpoint) EY of the viewer DR, who is an occupant (driver, etc.) of the vehicle 1, located at the eye box EB, via the optical path L2.

[0045] As a result, the image generated by the second display unit 11B is perceived as a virtual image V on the virtual image display surface VS.

[0046] Next, refer to Figure 3. Figure 3 shows an example of virtual image display and an example of real image display using a head-up display. In Figure 3, parts common to Figure 2 are denoted by the same reference numerals.

[0047] In Figure 3, vehicle 1 is traveling on road surface 4. During this travel period, for example, a virtual image V1 such as a road sign can be displayed on a virtual virtual image display surface VS that is inclined at a predetermined angle with respect to road surface 4.

[0048] Furthermore, inside the vehicle 1, or in other words, inside the windshield WS, a real image RV1 of a guide icon that guides the driver along a driving route can be displayed on a virtual real image display surface RS.

[0049] In this embodiment, the switching between the virtual image V1 and the real image RV1 is performed by electrical control, and by employing parallel control and multiple linked controls, it is possible to achieve high-speed switching while preventing the images from overlapping in time.

[0050] Next, refer to Figure 4. Figures 4(A) and 4(B) show examples of lens configurations in the first and second display units, respectively. In Figure 4, parts common to the previously shown drawings are denoted by the same reference numerals.

[0051] Figure 4(A) shows an example of the lens configuration of the first display unit 11A. The first display unit 11A includes a light source circuit board 12A, a plurality of light-emitting elements (LEDs, etc.) 122A formed on the light source circuit board 12A, a condenser lens 123A, a first lenticular lens 124A for the first display unit, a second lenticular lens 125 for the first display unit, a diffuser plate 127A, and a first liquid crystal display unit (liquid crystal panel) 126A.

[0052] The emission surface of the second lenticular lens 125 is a toroidal surface with a convex shape. By forming the emission surface convex, the light distribution characteristics can be narrowed in both the H and V directions.

[0053] The display light generated by the first display unit 11A travels along the optical path L1, passing through the first curved mirror (curved lens) 22, the second curved mirror 24 (not shown in Figure 4(A)), and the windshield WS, and reaches the eye box EB. As a result, the real image RV is displayed.

[0054] Figure 4(B) shows an example of the lens configuration of the second display unit 11B. The second display unit 11B includes a light source circuit board 12B, a plurality of light-emitting elements (LEDs, etc.) 122B formed on the light source circuit board 12B, a condenser lens 123B, a first lenticular lens 124B for the second display unit, a second lenticular lens 129, a diffuser plate 127B, and a second liquid crystal display unit (liquid crystal panel) 126B.

[0055] The emission surface of the second lenticular lens 129 is a concave toroidal surface. By forming the emission surface concave, the light distribution characteristics can be widened in both the H and V directions.

[0056] The display light generated by the second display unit 11B travels along the optical path L2, passing through the first curved mirror (curved lens) 22, the second curved mirror 24 (not shown in Figure 4(A)), and the windshield WS, and reaches the eye box EB. As a result, the virtual image V is displayed.

[0057] Next, refer to Figure 5. Figure 5 shows an example of the configuration of a display control device and an example of display control by the display control device.

[0058] The display control device (or display device) 50 includes a first control unit 13A and a second control unit 13B. The display control device 50 (the first control unit 13A and the second control unit 13B) is a controller that oversees the control of the first display unit 11A and the second display unit 11B, and includes a processor composed of electronic circuits (hardware) that realize predetermined functions by executing a program (software). That is, the display control device 50 can be composed of various processors such as a CPU, MPU, GPU, DSU, FPGA, ASIC, etc. The display control device 50 may be composed of one or more processors.

[0059] The first control unit 13A supplies a video signal VID1 and a control signal TFTC1 to the first liquid crystal panel (first liquid crystal display unit) 126A, which uses a TFT (Thin Film Transistor) included in the first display unit 11A, and also supplies a control signal BL1 to the first backlight (first light source unit) 9A.

[0060] The second control unit 13B supplies the video signal VID2 and the control signal TFTC2 to the second liquid crystal panel (second liquid crystal display unit) 126B, which uses a TFT included in the second display unit 11B, and also supplies the control signal BL2 to the second backlight (second light source unit) 9B.

[0061] The display control device 50 performs a predetermined startup sequence and a predetermined shutdown sequence when starting up and shutting down the first and second display units 11A and 11B.

[0062] Note that the control signals "TFTC1, TFTC2, BL1, BL2" mentioned above are general terms, and in reality, multiple types of control signals are used. This will be explained later.

[0063] Furthermore, each startup and shutdown sequence is a control that sequentially advances each stage of control according to a predetermined order or procedure, and the startup sequence includes a first startup stage that releases the reset of the first and second display units 11A and 11B, a second startup stage that starts inputting video signals to the first and second display units 11A and 11B, a third startup stage that inputs a display on command to the first and second display units 11A and 11B to turn on the display, and a fourth startup stage that lights up the first and second backlights 9A and 9B of the first and second display units 11A and 11B.

[0064] The termination sequence includes a first termination stage in which the first and second backlights 9A and 9B of the first and second display units 11A and 11B are turned off; a second termination stage in which a display off command is input to the first and second display units 11A and 11B to turn them off; a third termination stage in which the input of video signals to the first and second display units 11A and 11B is terminated; and a fourth termination stage in which the first and second display units 11A and 11B are reset.

[0065] In the above startup and shutdown sequences, the sequence is completed when all stages are executed. However, if the sequence is stopped at an intermediate stage, the first and second display units 11A and 11B are designed to reduce current consumption by entering a low-power mode in which current consumption is set lower than during normal operation.

[0066] Next, refer to Figures 6 and 7. Figure 6 is a timing chart showing an example of interlocking control by the display control device in Figure 5. Figure 7 is a timing chart of a comparative example with respect to Figure 6.

[0067] First, refer to the comparative example in Figure 7 (an example that does not use the display control of the present invention). In Figure 7, at time t1, the "first TFT-RES and second TFT-RES, which are control signals to release the reset" supplied to the first and second liquid crystal panels 126A and 126B, respectively, are both at the L level (in other words, the inactive level).

[0068] At time t2, the first TFT-RES reaches the H level (in other words, the active level), and the reset of the first liquid crystal panel 126A in the first display unit 11A is released, making it operational. Subsequently, at time t9, the first TFT-RES reaches the L level (inactive level), and the display on the first display unit 11A ends.

[0069] Next, at time t15, the control signal, the second TFT-RES, goes to the H level (active level), releasing the reset of the second liquid crystal panel 126B in the second display unit 11B, making it operational. Then, at time t16, the second TFT-RES goes to the L level (inactive level), ending the display on the second display unit 11B.

[0070] In the example shown in Figure 7, the display operation of the second display unit 11B begins after the display operation of the first display unit 11A has finished, so it is unavoidable that the display switching time will be long.

[0071] Therefore, in the display control of this embodiment shown in Figure 7, the processing of either the first or second display unit 11A, 11B and the processing of the other are superimposed in time and processed in parallel to speed up the display switching.

[0072] However, in this case, with individual control where each process is performed separately, if a delay occurs in either process, the other process will continue without being aware of the delay, increasing the likelihood that, for example, the first and second backlights 9A and 9B will turn on simultaneously. Also, if processes are performed in parallel, both display units 11A and 11B will be in operation, inevitably increasing power consumption (current consumption).

[0073] In this embodiment, the problem of increased power consumption (current consumption) is addressed by, as explained earlier, optimizing the startup and shutdown sequences so that when the device is stopped at an intermediate stage, it enters standby mode, maintaining a low power consumption state, thereby minimizing the increase in current consumption.

[0074] On the other hand, to avoid the risks associated with simultaneous display due to parallel processing, measures are taken by sequentially executing three interlocking controls (the first, second, and third interlocking controls).

[0075] Here, "interlocked control," unlike "individual control," is a timing control method in which the timing of one operation is linked to the timing of another operation. This has the effect that once the timing of one operation is determined, the timing of the other operation is automatically determined.

[0076] Therefore, if a delay occurs in one timing, the other timing will also be delayed accordingly, ensuring that the relative time relationship between the two timings is always maintained as designed. Thus, simultaneous activation of the two backlights 9A and 9B can be reliably prevented.

[0077] In this way, simultaneous backlight activation is reliably prevented, unnecessary margins (to avoid duplication) are minimized, and time is thoroughly reduced. This ensures a safe and significantly shorter switching time compared to conventional methods.

[0078] Furthermore, the "first interlocking control" described above is a process in which, when the reset is released for either the first or second display unit 11A or 11B and the first startup stage is executed, the other display unit also starts the first startup stage (reset release) in parallel with the start timing of the startup stage of the other display unit (specifically, it may be simultaneously, or it may be at a predetermined time elapsed from the start timing).

[0079] In a preferred embodiment, the "second interlocking control" described above is, for example, "when the input of a video signal is started for either the first or second display unit 11A or 11B to execute the second startup stage, the second startup stage (input of a video signal) is also started in parallel for the other display unit, in conjunction with the timing of the start of the input of the video signal in the other display unit or the timing of the end of the input of the video signal in the other display unit."

[0080] Subsequently, only one of the display units performs a third startup stage (display on state) by inputting a display on command, and a fourth startup stage (backlight on) by lighting up either the first or second backlight 9A or 9B, thereby initiating the display of the image on the one of the display units.

[0081] The "third interlocking control" described above is a process that, when either of the display units displaying the video then performs one of the first to fourth termination stages (display off state, backlight off, video signal stop, reset) to terminate the display, during the termination period of the display, the third activation stage (display on state) by inputting a display on command in the other of the first and second display units 11A and 11B, and the fourth activation stage (backlight on) by turning on the other of the first and second backlights, are performed in parallel, and the lighting period of one of the first and second backlights 9A and 9B does not overlap with the lighting period of the other of the first and second backlights 9A and 9B. Note that the "third interlocking control" may also include the video signal input stage in the other display unit (for example, in the cases of Figures 9 and 10; this will be discussed later).

[0082] The timing control shown in Figure 6 will be explained step by step below. In the figure, "Min-I," "Normal-I," and "Low-I" refer to "minimum operating current," "normal operating current in normal operating mode," and "low power consumption current in low power consumption mode," respectively.

[0083] Furthermore, "DONC" is a display-on command (a command to turn the display on), and "DOFC" is a display-off command (a command to turn the display off).

[0084] In Figure 5, at time t1, the "first TFT-RES" and "second TFT-RES," which are control signals to release the reset, supplied to the first and second liquid crystal panels 126A and 126B respectively, are both at the L level (in other words, the inactive level).

[0085] At time t2, the first TFT-RES reaches the H level (in other words, the active level), and the reset of the first liquid crystal panel 126A in the first display unit 11A is released, making it operational. In conjunction with the timing of this change of the first TFT-RES to the H level (synchronously and simultaneously in the example of Figure 5), the second TFT-RES also reaches the H level (active level) (first linked control).

[0086] Next, at time t3, the video signal VID1 is supplied to the first display unit 11A. In conjunction with the timing of this video signal supply (synchronously and simultaneously in Figure 5), the video signal VID2 is also supplied to the second display unit 11B (second linked control).

[0087] Next, at time t4, the display on command DONC is input to the first display unit 11A, which turns the first display unit 11A into a display-on state. Subsequently, at time t5, after a predetermined time ΔT1 has elapsed from time t3, the first backlight 9A is turned on, and the display of the image on the first display unit 11A begins.

[0088] Subsequently, at time t6, the first backlight 9A is turned off. At time t7, after a predetermined first delay time ΔT2 has elapsed from time t6, the display off command DOFC is input, causing the first display unit 11A to turn off. Then, at time t8, after a predetermined time ΔT3 has elapsed from time t7, the input of the video signal VID1 ends, and subsequently, at time t9, after a predetermined time ΔT4 has elapsed from time t8, the first TFT-RES goes to L level (inactive level), and the first display unit 11A is reset.

[0089] Meanwhile, at time t6, the display on command DONC is input to the second display unit 11B, which causes the second display unit 11B to enter the display on state. Subsequently, at time t7, after the first delay time ΔT2 has elapsed from time t6, the second backlight 9B is turned on, and the display of the image on the second display unit 11B begins (third interlocking control).

[0090] Subsequently, at time t10, the second backlight 9B is turned off, and at time t11, the display off command DOFC is input, causing the second display unit 11B to turn off. Then, at time t12, the input of the video signal VID2 ends, and subsequently, at time t13, the second TFT-RES goes to L level (inactive level), and the first display unit 11A is reset. At time t14, the first and second display units 11A and 11B are both in a non-display state.

[0091] During the third interlocking control period, as described above, the first backlight 9A is turned off at time t6 (first timing), eliminating the possibility of both backlights 9A and 9B being lit simultaneously. Therefore, the second display unit 11B can be turned on at time t6 (first timing), in other words, at the shortest possible timing without redundant time buffers, thereby shortening the time required for switching displays.

[0092] Furthermore, in the second display unit 11B, the second backlight 9B is turned on at time t7 (second timing), which is after a first delay time ΔT2 has elapsed from time t6 (first timing).

[0093] This interlocking control ensures that the second backlight 9B in the second display unit 11B is turned off at time t7 (second timing), which is after a first delay time ΔT2 has elapsed from time t6 (first timing) when the first backlight 9A in the first display unit 11A is turned off. There is always a "first delay time ΔT2" between the off states of each backlight 9A and 9B, thus reliably preventing the simultaneous illumination of both backlights 9A and 9B. Therefore, the inconvenience of the two display units 11A and 11B operating and displaying an image simultaneously does not occur.

[0094] Thus, according to the display control shown in Figure 6, time is reduced by minimizing the time margin, and a third interlocking control is implemented so that a predetermined delay time (first delay time) ΔT2 is provided between the off timings of the two backlights 9A and 9B. Therefore, the termination process of the first display unit 11A and the activation process of the second display unit 11B can be performed in parallel without any wasted time, and simultaneous illumination of the two backlights 9A and 9B can be reliably prevented.

[0095] Next, refer to Figure 8. Figure 8 is a flowchart showing the main control procedures corresponding to the interlocking control in Figure 6.

[0096] As explained earlier, in the example shown in Figure 6, the startup and shutdown sequences of the first and second display units are controlled in parallel and in conjunction (interlocking control of the first to third units).

[0097] In step S1, the first interlocking control is performed. In this step S1, the activation (reset release) of one of the display units is linked to the activation (reset release) of the other display unit.

[0098] In step S2, a second interlocking control is performed. In this step S2, the activation of one display unit (start of video signal input) is synchronized with the activation of the other display unit (start of video signal input).

[0099] Next, in step S3, image display is started on one of the display units. In step S3, one of the display units is activated (display on state, backlight on) and starts displaying an image on that unit. At this time, the other display unit is in the process of activating (reset released, video signal input stage) and is in standby mode, so the low power consumption state continues and an increase in power consumption is not a particular problem.

[0100] Next, in step S4, a third interlocking control is performed. In this step S3, the shutdown of one display unit (backlight off, display off state) and the activation of the other display unit (display on state, backlight on) are linked, eliminating unnecessary delays and accelerating the activation of the other display unit. At the same time, the operation timing is controlled so that a delay time (first delay time) ΔT2 is always present between the backlight off of one display unit and the backlight on of the other.

[0101] (Second embodiment) Refer to Figure 9. Figure 9 shows another example of the configuration of the display control device and another example of display control by the display control device. In Figure 9, parts common to Figure 5 are denoted by the same reference numerals.

[0102] The basic configuration and operation of the display device in Figure 9 are the same as those of the display device in Figure 5. In other words, the display control device (or display device) 50 has a first control unit 13A and a second control unit 13B. The first control unit 13A supplies a video signal VID1 and a control signal TFTC1 to the first liquid crystal panel (first liquid crystal display unit) 126A which uses a TFT included in the first display unit 11A, and also supplies a control signal BL1 to the first backlight (first light source unit) 9A.

[0103] The second control unit 13B supplies the video signal VID2 and the control signal TFTC2 to the second liquid crystal panel (second liquid crystal display unit) 126B, which uses a TFT included in the second display unit 11B, and also supplies the control signal BL2 to the second backlight (second light source unit) 9B.

[0104] Furthermore, the display control device 50 performs a predetermined startup sequence and a predetermined shutdown sequence when starting up and shutting down the first and second display units 11A and 11B.

[0105] However, in Figure 9, the two video signals VID1 and VID2 are supplied via a common signal line, and the selector 52 is switched as appropriate so that video signal VID1 is supplied to the first liquid crystal panel 126A and video signal VID2 is supplied to the second liquid crystal panel 126B. In this respect, it differs from the figure.

[0106] In Figure 9, signal line LN1, which supplies video signal VID1, and signal line LN2, which supplies video signal VID2, are connected to a common signal line LN3 at a common connection point. Each video signal VID1 and VID2 is supplied (transmitted) to selector 52 via this common signal line LN3.

[0107] The first control unit 13A supplies the selector 52 with an output destination switching control signal ACT1 at an appropriate timing during the video signal switching period, and similarly, the second control unit 13B supplies the selector 52 with an output destination switching control signal ACT2 at an appropriate timing during the video signal switching period.

[0108] These output destination switching control signals ACT1 and ACT2 control the path of the selector 52, in other words, the output destination (supply destination or switching destination) of the video signals VID1 and DID2, and therefore, each video signal VID1 and VID2 is supplied to the first and second liquid crystal panels 126A and 126B, respectively.

[0109] This configuration allows for the common (unified) signal lines supplying video signals. Therefore, the configuration for supplying each video signal VID1 and VID2 to the first and second display units 11A and 11B is simplified.

[0110] Next, refer to Figures 10 and 11. Figure 10 is a timing chart showing an example of linked control by a display control device in the example of Figure 9. Figure 11 is a timing chart of a comparative example with respect to Figure 10.

[0111] First, refer to the comparative example in Figure 11 (an example that does not use the display control of the present invention). In Figure 11, the timing of the "first TFT-RES and second TFT-RES, which are control signals to release the reset" supplied to the first and second liquid crystal panels 126A and 126B respectively is the same as in the example in Figure 7.

[0112] In other words, even in the example shown in Figure 11, since the display operation of the second display unit 11B starts after the display operation of the first display unit 11A has finished, it is undeniable that the display switching time is long.

[0113] However, Figure 11 differs from Figure 7 in that time t2 to t6 is the input period for video signal VID1, and at time t6, the supply of video signal VID2 begins, and time t6 to t16 is the input period for video signal VID2.

[0114] In the example in Figure 11, the input timing of the video signal VID2 is later than in the example in Figure 7. Therefore, if the input timing of the video signal VID2 is delayed for any reason, the first and second backlights 9A and 9B may turn on simultaneously. Thus, when adopting a configuration like that in Figure 11, it is necessary to take more careful measures, taking into account the possibility of delays in the input timing of the video signal VID2.

[0115] Refer to Figure 10. The operation in Figure 10 from time t1 to t7 is the same as in Figure 6, which was explained earlier, except for the part related to the input of the video signal.

[0116] However, in the example shown in Figure 10, at time t3, only the video signal VID1 is input to the first display unit 11A. The video signal VID2 is input to the second display unit 11B at time t7.

[0117] In other words, in the example shown in Figure 10, the second interlocking control starts the input of the image signal VID2 to the second display unit 11B in conjunction with time t7, which is the "end timing" of the video signal VID1 in the first display unit 11A.

[0118] Therefore, the input timing of the video signal VID2 to the second display unit 11B is delayed compared to the example in Figure 5, which reduces the time margin and makes it difficult to control the lighting of the second backlight 9B. In other words, countermeasures must be taken to account for cases where the timing of the video signal VID2 in the second display unit 11B is delayed for any reason.

[0119] In the example in Figure 10, similar to the example in Figure 6, the first backlight is turned off at time t6 (first timing) in the first display unit 11A.

[0120] At time t7 (second timing), after a predetermined first delay time ΔT2 has elapsed from time t6, the first display unit 11A simultaneously receives the display off command DOFC and stops the video signal VID2. As a result, the first display unit 11A enters a display-off state, and the video signal VID2 is also stopped at the same time.

[0121] In the second display unit 11B, the input of video signal VID2 is started in conjunction with time t7 (second timing). In other words, at time t7 (second timing), the switching between video signals VID1 and VID2 is performed.

[0122] The switching process of video signals VID1 and VID2 at this time t7 (the second timing) belongs to the second interlocking process described earlier, but it can also be considered the start process of the third interlocking process that follows the second interlocking process, and therefore may be included in the third interlocking process.

[0123] Next, at time t8' (third timing), after a predetermined "second delay time ΔT3" has elapsed from time t7 (second timing), the display on command DONC is input to the second display unit 11B, and the display is turned on.

[0124] Next, at time t8'' (the fourth timing), after a predetermined "third delay time ΔT5" has elapsed from time t8' (the third timing), the second backlight 9B is turned on (illuminated).

[0125] According to the above-described interlocking control, after the first backlight 9A in the first display unit 11A is turned off at time t6 (first timing), a "first delay time ΔT2", a "second delay time ΔT3", and a "third delay time ΔT5" occur before the second backlight 9B in the second display unit 11B is turned on.

[0126] In the example shown in Figure 6, only the first delay time ΔT2 was present. However, in the example shown in Figure 10, taking into consideration unforeseen circumstances such as delays that occur when switching video signals, a second and third delay time ΔT3 and ΔT5 are provided as a precaution to prevent simultaneous on-up of the two backlights 9A and 9B.

[0127] As a result, in the example shown in Figure 10, the termination of the video signal VID1 for the first display unit 11A and the start of the video signal VID2 for the second display unit 11B can be performed simultaneously at the same time (time t7 as the second timing), and the termination process for the first display unit 11A and the activation process for the second display unit 11B (start of image display) can be performed in parallel without any wasted time, and by providing a sufficient delay time, simultaneous illumination of the two backlights 9A and 9B can be reliably prevented.

[0128] Next, refer to Figure 12. Figure 12 is a flowchart showing the main control procedures corresponding to the interlocking control in Figure 10. In Figure 12, steps common to Figure 8 are denoted by the same reference numerals.

[0129] First, in step S1, the first interlocking control is performed. In step S1, as explained earlier, the activation (reset release) of one of the display units is linked to the activation (reset release) of the other display unit.

[0130] In step S5, image display is started in the second display unit 11B. In step S5, a startup process (input of video signal, display ON state, backlight ON) is performed in one of the display units, thereby starting image display in one of the display units. Meanwhile, the other display unit is in standby mode during the startup process (reset release stage). The low power consumption state will continue.

[0131] In step S6, a second interlocking control is performed. In this step S6, the termination stage of one of the display units (end of video signal) is linked to the activation stage of the other display unit (start of video signal). At this time, from the backlight off in one of the display units, The time from the display turning off to the end of the video signal (in other words, the start of the video signal from either the other display unit) is defined as the first delay time ΔT2.

[0132] In step S7, a third type of interlocking control is performed. In step S7, the shutdown (startup reset) of one of the display units is synchronized with the startup (display on state, backlight on) of the other display unit, eliminating unnecessary delays and speeding up the startup of the other display unit. At the same time, the time from the start of the video signal in the other display unit to the display on state is set to ΔT3. By defining ΔT5 as the time from the display-on state to the backlight-on state, the operating timing is controlled so that "a first delay time ΔT2 + a second delay time ΔT3 + a third delay time ΔT5" is always intervened between the backlight-off state of one display unit and the backlight-on state of the other display unit.

[0133] As described above, according to the embodiments of the present invention, it is possible to realize a display control device, a display device such as a head-up display, and a display control method that can switch between virtual and real images at high speed while providing a period during which no images are displayed simultaneously in each display unit. Furthermore, power consumption can be effectively suppressed.

[0134] The present invention is not limited to the embodiments described above, and can be modified and applied in various ways. For example, in the embodiments described above, a windshield is used as the projection member (light-transmitting member), but the invention is not limited to this, and a flat glass or a combiner may also be used.

[0135] The present invention is not limited to the exemplary embodiments described above, and those skilled in the art will be able to easily modify the exemplary embodiments described above to the extent included in the claims.

[0136] For example, the present invention can be further modified and applied as shown in Figures 13 to 15 (third to fifth embodiments). The third to fifth embodiments will be described in order below.

[0137] Refer to Figure 13. Figure 13 is a timing chart showing an example of interlocking control by a display control device according to the third embodiment. Figure 13 is almost identical to Figure 6 of the first embodiment described earlier. However, in Figure 13, a completely black screen display process is performed in the second display unit 11B (second liquid crystal display unit 126B), which is different from Figure 6. In Figure 13, as in Figure 6, the on-times of the two light sources (backlights) 9A and 9B must not overlap. However, during the non-overlapping period (the backlight off period), each of the two display units 11A and 11B is capable of displaying an image. In other words, the display-on periods (periods during which images can be displayed) of the two display units 11A and 11B overlap in time. Therefore, for example, it is conceivable that external light (such as sunlight or light from lighting fixtures) entering the housing of the display device (HUD device) 100 may become stray light, and this stray light may cause the screen of the second display unit 11B, which is normally not displayed, to become slightly brighter. In this case, the viewer may visually perceive the two display units 11A and 11B (two liquid crystal display units 126A and 126B), making it difficult to see. To suppress this inconvenience, the third embodiment implements a fully black screen display process. In other words, a black image is inserted into the video signal VID2 of the second display unit 11B (second liquid crystal display unit 126B) whose display operation has started, and during the period from time t6 to t7 when the two light sources (two backlights) 9A and 9B are not turned on at the same time, the screen (image display area) of the second display unit 11B (second liquid crystal display unit 126B) is set to a fully black screen, and this fully black screen is used as a mask to prevent the emission of unwanted light. This makes it possible to suppress the above-mentioned inconvenience. Now, refer to Figure 14. Figure 14 is a flowchart showing the main control procedure of the third embodiment (Figure 13). In step S100, the startup and shutdown sequences of the first and second display units are controlled in parallel and in conjunction with each other. In step S101, during the period when the display ON states of the first and second display units overlap, but the ON periods of the two backlights do not overlap, the video signal of the second display unit is treated as a black signal, and a completely black screen is displayed.

[0138] Next, refer to Figure 15. Figure 15 is a timing chart showing an example of interlocking control by the display control device according to the fourth embodiment. In Figure 15, unlike Figure 6 of the first embodiment described earlier, it is permissible for the on periods of the two light sources (backlights) 9A and 9B to partially overlap during the switching period. In other words, overlapping illumination suppression control is implemented so that the on-time of the first light source (backlight) 9A and the on-time of the second light source (backlight) 9B do not overlap for a certain period of time. During that period, simultaneous on-time of each light source (backlight) 9A and 9B is prohibited, thereby achieving lower power consumption. In Figure 15, the parallel control and interlocking control described earlier in Figure 6 are also implemented. For example, in Figure 15, with respect to the interlocking control, when the first display unit 11A enters the display-on state (display-ready state) at time t4, the timing (time t5) for the first backlight 9A to turn on is determined, followed by the timing (time t15) for supplying the video signal (image signal) to the second display unit 11B, followed by the timing (time t16) for the second display unit 11B to enter the display-on state (display-ready state), followed by the timing (time t17) for the second backlight 9B to turn on. Here, let T2 be the period from time t4 to time t18. In other words, time t18 is the point at which period T2 has elapsed from time t4, and this time t18 marks the end of the switching period (the period between the two thick dashed lines in the diagram). Furthermore, time t15 is the point at which period T7 has elapsed from time t4, and this time t15 marks the start of the transition period. The transition period is precisely determined as period T8, from time t15 to t18. Furthermore, time t16 is the point in time when the period T9 has elapsed from time t15, and this time t16 is the timing when the second display unit 11B becomes display-on (display-ready). Furthermore, time t17 is the point in time when period T10 has elapsed from time t16, and this time 17 is when the second backlight 9B turns on. Furthermore, the period T11 from time t17 to t18 is the period in which the ON periods of the first and second backlights 9A and 9B overlap. In Figure 15, during the switching period T8 (time t15~t18), a black image is supplied to the second display unit 11B (second liquid crystal display unit 126B), and a completely black screen is displayed during this period. During the switching period, both display units 11A and 11B are capable of displaying images, and the illumination periods of the light sources (backlights) 9A and 9B also overlap. Therefore, it is not impossible that, for example, some image may be displayed on the screen of the second display unit (backlight) 9B, which is normally not supposed to be displayed. In this case, the viewer DR will perceive both display units 11A and 11B (two liquid crystal display units 126A and 126B) visually, making it difficult to see. Therefore, in the second display unit 11B, where the display operation has started, a black video signal VID2 is supplied for at least a portion of the switching period T8 (time t15~t18), causing the screen (image display area) of the second display unit 11B to display a completely black screen, and this completely black screen is used as a mask to prevent the emission of unwanted light. This makes it possible to suppress the above-mentioned problems. In Figure 15, the screen is completely black for the entire duration of the switching period T8, but this is not the only option. For example, it is preferable to have a completely black screen during the period T11 in which the ON periods of at least two light sources (backlights) 9A and 9B overlap. Furthermore, in Figure 15, the first display unit 11A (first liquid crystal display unit 126A) where the display ends implements a "video display for display termination" (a continuous image display in time, which can also be called an animation display) that can notify the viewer DR of the end of the image display. In Figure 15, diagonal lines are used to indicate the period during which video is inserted in the video signal (image signal) VID1 supplied to the first display unit 11A. In this video display, image erasure techniques such as slide-out, fade-out, and zoom-out, as shown earlier in Figure 1(D) d1 to d3, can be employed. Slideout is an image erasure method that moves the position of the displayed image on the screen, gradually erasing it over time. Fade-out is an image removal method that gradually reduces the brightness (luminance) of an image displayed on the screen over time, thereby gradually making the image disappear. Zooming out is an image removal method that gradually reduces the size of the displayed image on the screen over time, thereby gradually erasing the image. By using these methods, the display of images can be terminated without causing discomfort to the viewer. As shown in Figure 6 above, during the display switching period, there is a blank period in which no image is displayed in either of the two display units 11A or 11B. In contrast, in Figure 15, the first display unit 11A (first liquid crystal display unit 126A) where the image display ends displays a moving image (a temporally continuous image) suitable for notifying the end of the display. This results in a transition that provides the viewer DR with a less abrupt and more natural visual experience. Furthermore, in Figure 15, the all-black screen on the second display unit 11B is canceled and the normal image is displayed in conjunction with (specifically synchronized with) the timing when the video for ending the display ends (time t18). As a result, when the video display ends on the first display unit 11A, the normal display can start on the second display unit 11B without delay, and there is no blank period during which no image is displayed. Therefore, in this respect as well, a more natural and accurate switching can be achieved. Furthermore, by actually using the display device (HUD device 100), the viewer DR can empirically learn that when the video indicating the end of the display finishes being displayed on the first display unit 11A, the image display starts on the second display unit 11B. Here, since the time from the start to the end of the video used to mark the end of the display is fixed (period T8 in Figure 15), the viewer DR can predict how much time will have passed since the video started on the first display unit 11A before the image display on the second display unit 11B begins, thus increasing their sense of security. Therefore, a more natural, accurate, and reassuring display switching experience with superior visual appeal is achieved. Now, refer to Figure 16. Figure 16 is a flowchart showing the main control procedure of the fourth embodiment (Figure 15). In step S200, the startup and shutdown sequences of the first and second display units are controlled in parallel and in conjunction with each other. In step S201, for at least a portion of the switching period (the period during which at least two backlights are turned on at the same time), the video signal on the second display unit is treated as a black signal, resulting in a completely black screen display, and the first display unit displays a video signal to indicate the end of the display (slide out, fade out, zoom out, etc.).

[0139] Next, refer to Figure 17. Figure 17 is a timing chart showing an example of interlocking control by the display control device according to the fifth embodiment. Figure 17 shows the same timing control as Figure 15, which was explained earlier. However, in Figure 17, during the period T11 from time t17 to t18 (the period in which the ON periods of the first and second light sources (each backlight) 9A and 9B overlap), a dimming process is performed to reduce the illumination intensity of the second light source (backlight) 9B from the normal illumination intensity, which is different from Figure 15. In other words, the second display unit 11B displays a completely black screen, and the second light source unit 9B performs dimming processing in the second light source unit (second backlight) for at least a portion of the period during which the completely black screen is displayed (preferably, the period during which the completely black screen display period and the ON period of the second light source unit 9B overlap). As explained earlier, the all-black screen display functions as a mask to prevent the emission of unnecessary light, and at least during the all-black screen period, light emission from the light source is unnecessary. However, since it takes time to relight the light source if the second light source unit 9B is turned off, dimming is performed. This further reduces (suppresses) power consumption. Now, refer to Figure 18. Figure 18 is a flowchart showing the main control procedure of the fifth embodiment (Figure 17). In step S300, the startup and shutdown sequences of the first and second display units are controlled in parallel and in conjunction with each other. In step S301, for at least a portion of the switching period (a period during which at least two backlights are turned on at the same time), the video signal on the second display unit is set to a black signal to display a completely black screen, and the first display unit displays a video signal to indicate the end of the display (slide out, fade out, zoom out, etc.), and for at least a portion of the completely black screen display period (preferably a period during which the completely black screen display period and the on period of the second light source unit (second backlight) overlap), the second light source unit (second backlight) performs a dimming process.

[0140] As described above, according to the embodiments of the present invention, it is possible to realize a display control device, a display device such as a head-up display, and a display control method that can switch between virtual and real images at high speed while reliably preventing images from being displayed simultaneously in each display unit, and it is also possible to effectively suppress power consumption and switch between displays with images that are easy for the viewer to see. [Explanation of Symbols]

[0141] 1. Vehicle, 2...Optical system, 9A, 9B...First and second light source units (first and second backlights), 11A, 11B...First and second display units, 12A, 12B... Circuit boards for light sources, 13A, 13B... First and second control units (display control units), 17... Ejection window, 19... cabinet, 22...First curved mirror (curved lens), 24. A second curved mirror (concave mirror, etc.), 50...Display control device, 52...Selector, 100... Display devices (Head-Up Display (HUD) devices), 122A, 122B... Light-emitting elements (e.g., LEDs), 123A, 123B... Capacitor lens, 124A...First lenticular lens for the first display unit, 124B...First lenticular lens for the second display section, 125...Second lenticular lens for the first display section, 129...Second lenticular lens for the second display section, 126A, 126B...First and second liquid crystal display units (first and second liquid crystal panels) 127A, 127B... Diffuser plate, 130A, 130B... Circuit board WS...windshield, EB... Eyebox, DR... Sighted person (passenger, driver), EY... eye (perspective), RV...the reality, V...Illusion, L1, L2... First and second optical paths.

Claims

1. A display device having a first image generation unit comprising a first light source unit and a first display unit, and a second image generation unit comprising a second light source unit and a second display unit, wherein the display device is capable of switching between displaying a first image or a second image by switching between using the first and second image generation units, and a display control device for controlling the switching between the first and second images, The display control device has a control unit, The control unit, During the switching period in which the display by one of the first or second image generation units ends and the display by the other image generation unit begins, Parallel control, which causes the display start operation in the other image generation unit to be performed in parallel with the display end operation in the other image generation unit. And, Interlocking control is implemented to determine the operating timing of the other image generation unit, starting from the operating timing of one of the aforementioned image generation units. During the switching period, control is implemented to suppress overlapping illumination so that the on-period of the light source in either of the image generation units and the on-period of the light source in the other image generation unit do not overlap in time for at least a portion of the period. Display control device.

2. The control for terminating the display by either the first or second image generation unit, and the control for starting the display by the other image generation unit, is a sequence control that sequentially carries out the control of each stage in a plurality of stages according to a predetermined order or procedure, In the aforementioned parallel control, The sequence is completed when all of the aforementioned multiple stages are executed, but if it is stopped at an intermediate stage, the display unit of either of the image generation units and the display unit of the other image generation unit will be in a low-power consumption mode in which the current consumption is set lower than during normal operation. The display control device according to claim 1.

3. The control unit, In the aforementioned interlocking control, a predetermined time difference is set between the off timing of the display unit of either of the image generation units and the on timing of the display unit of the other image generation unit. This enables the suppression of overlapping illumination control by preventing temporal overlap between the on-period of the light source of one of the image generation units and the on-period of the light source of the other image generation unit. The display control device according to claim 1.

4. The aforementioned vehicle display control device is mounted on a vehicle and is capable of switching between displaying a virtual image or a real image as an image to a viewer who is a passenger in the vehicle, The first display unit is a display unit for displaying a virtual image, equipped with a first backlight. The second display unit is a display unit for displaying a real image, equipped with a second backlight. Furthermore, the control unit can switch between using the first and second display units. The activation of the first and second display units is performed by a startup sequence. The termination of the display in the first and second display units is performed by an termination sequence. The aforementioned startup and shutdown sequences are control methods that sequentially advance each stage of control according to a predetermined order or procedure. The aforementioned startup sequence is: A first startup step in which the reset of the first and second display units is released, A second startup step in which the input of video signals to the first and second display units is initiated, A third startup step involves inputting a display-on command to the first and second display units to turn on the display, A fourth startup step in which the first and second backlights in the first and second display units are turned on, Includes, The aforementioned termination sequence is: A first termination step in which the first and second backlights in the first and second display units are turned off, A second termination step involves inputting a display off command for the first and second display units to turn off the display, A third termination step which terminates the input of video signals to the first and second display units, A fourth termination step in which the first and second display units are reset, Includes, In the aforementioned startup and shutdown sequences, the sequence is completed when all stages are executed. However, if the sequence is stopped at an intermediate stage, the first and second display units enter a low-power consumption mode in which the current consumption is set lower than during normal operation. The control unit of the display control device is When the reset is released for either the first or second display unit and the first startup stage is executed, a first linked control is performed on the other display unit to start the first startup stage in parallel with the start timing of the startup stage of the other display unit. and, When the input of a video signal is started to either the first or second display unit and the second startup step is executed, a second linked control is also performed on the other display unit to start the second startup step in parallel, in conjunction with the timing of the start of the video signal input in the other display unit or the timing of the end of the video signal input. Subsequently, the third startup step, triggered by the input of the display on command, and the fourth startup step, triggered by the illumination of either the first or second backlight, are performed only in one of the aforementioned display units, thereby initiating the display of the image in the one of the aforementioned display units. Subsequently, if the display unit that is displaying the video performs the first to fourth termination steps and terminates the display, during the termination period of that display, A third interlocking control is performed, which involves carrying out the third startup step, which is triggered by the input of the display on command in either the first or second display unit, and the fourth startup step, which is performed by lighting up either the first or second backlight, in parallel, and such that the lighting period of one of the first or second backlights does not overlap with the lighting period of the other of the first or second backlight. The display control device according to claim 1.

5. The aforementioned display control device is In the second interlocking control, if the second startup step is performed on the other display unit of the first or second in conjunction with the timing of the start of video signal input on either the first or second display unit, In the third interlocking control described above, The first termination step is performed in either the first or second display unit to turn off either the first or second backlight at a first timing, and then, at a second timing after a predetermined first delay time has elapsed from the first timing, the second termination step is performed to turn off the display. and, In either the first or second display unit, the third startup step is performed at the first timing to turn the display ON, and the fourth startup step is performed at the second timing to light up either the first or second backlight. The display control device according to claim 4.

6. The aforementioned display control device is In the second interlocking control described above, when the input of the video signal to either the first or second display unit ends, and the other display unit executes the second startup step to start inputting the video signal, In the third interlocking control described above, In either the first or second display unit, the first termination step is performed to turn off either the first or second backlight at a first timing, and then, at a second timing after a predetermined first delay time has elapsed from the first timing, the second and third termination steps are performed to turn off the display and terminate the input of the video signal. and, In either the first or second display unit, the second startup step is executed at the second timing to start inputting the video signal. At a third timing after a predetermined second delay time has elapsed from the second timing, the third startup step is executed to turn the display on. At the fourth timing, after a predetermined third delay time has elapsed from the third timing, the fourth startup step is executed to illuminate either the first or second backlight. The display control device according to claim 4.

7. The aforementioned display control device is When inputting the respective video signals to each of the first and second display units, A common signal line is used to supply the respective video signals, and the path of the selector connected to the common signal line is controlled by a selection signal, thereby determining which of the first or second display unit the video signals supplied via the common signal line are input to. The display control device according to claim 6.

8. The control unit, In the control for suppressing overlapping illumination, The on-time period of either one of the aforementioned light sources and the on-time period of the other aforementioned light source are prohibited from overlapping in time, During the period from the end of the ON period of the light source in either of the aforementioned image generation units until the start of the ON period of the light source in the other aforementioned image generation unit, a black video signal is supplied to the display unit in the other aforementioned image generation unit to perform a full black screen display process, resulting in a full black screen display. The display control device according to claim 1.

9. The control unit, In the control for suppressing overlapping illumination, During a portion of the aforementioned switching period, the on-period of the light source in one of the aforementioned image generation units and the on-period of the light source in the other aforementioned image generation unit are made to overlap in time, During at least a portion of the aforementioned switching period, a black video signal is supplied to the display unit of the other image generation unit to perform a full black screen display process, resulting in a full black screen display. The display control device according to claim 1.

10. The control unit, In parallel with the display of the all-black screen on the display unit of the other image generation unit, The display unit of either of the aforementioned image generation units will perform a video display to indicate the end of the display, In conjunction with the termination of the aforementioned video display, the all-black screen display in either of the aforementioned displays is canceled and the image is returned to normal. The display control device according to claim 9.

11. The aforementioned video display for ending the display is: This is an image display that slides out the displayed image. Or, This is an image display that fades out the displayed image. Or, This is an image display that zooms out the displayed image. The display control device according to claim 10.

12. The control unit, During at least a portion of the period in which the all-black screen display is performed in the display unit of the other image generation unit, A dimming process is performed to reduce the illumination intensity of the light source in the other image generation unit to a level lower than the normal illumination intensity. The display control device according to claim 9.

13. It is mounted in a vehicle and is capable of switching between a virtual image and a real image for the viewer, who is a passenger in the vehicle. A first display unit for displaying a virtual image, equipped with a first backlight, A second display unit for displaying a real image, equipped with a second backlight, A display control device according to any one of claims 1 to 12, A display device.

14. The aforementioned display device is A head-up display device having an emission window, which emits display light generated by the first or second display unit from the emission window, thereby allowing the viewer to see the virtual image and real image represented by the display light. The display device according to claim 13.

15. A display control method for controlling the switching between the first and second images of a display device having a first image generation unit comprising a first light source unit and a first display unit, and a second image generation unit comprising a second light source unit and a second display unit, wherein the first and second image generation units can be switched to display either a first image or a second image, the display control method for controlling the switching between the first and second images. During the switching period in which the display by one of the first or second image generation units ends and the display by the other image generation unit begins, Parallel control that causes the display start operation in the other image generation unit to be performed in parallel with the display end operation in the other image generation unit. And, Interlocking control is implemented to determine the operating timing of the other image generation unit, starting from the operating timing of one of the aforementioned image generation units. During the switching period, control is implemented to suppress overlapping illumination so that the on-period of the light source in either of the image generation units and the on-period of the light source in the other image generation unit do not overlap in time for at least a portion of the period. Display control method.

Images