Head-up display device, display control device, and display control method

Abstract

The present invention provides a head-up display (HUD) device that suppresses the inability to observe virtual images when view loss occurs or when view loss is likely to occur, thereby reducing discomfort. The head-up display (HUD) device, which is mounted on a vehicle and allows the visual recognition of a virtual image, comprises: a display unit (145) that displays an image; and a control unit (100) that performs view tracking lighting control to illuminate a partial area of ​​a view area (EB) according to the driver's view position. The control unit (100) controls the display unit (145) so that, when view loss occurs in which the view position cannot be detected or when view loss is likely to occur, the area of ​​pixels or light sources that contribute to the display of virtual images is expanded, and the illumination area that is illuminated immediately before the expansion and is wider than the partial illumination area of ​​the view area (EB) is illuminated.

Description

Technical Field

[0001] The present invention relates to a head-up display (HUD) device, a display control device, and a display control method for projecting image display light onto a projection target component such as a windshield or a combiner of a vehicle (passenger) to display a virtual image in front of the driver. Background Art

[0002] In a HUD device, since constant illumination (lighting) of the viewpoint area would result in considerable waste, from the perspective of energy conservation, a viewpoint tracking lighting (partial lighting) scheme has been proposed to illuminate a portion of the viewpoint area according to the driver's viewpoint position (for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6586646 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The present inventors have studied the case of detecting the viewpoint position of a driver (which can be broadly interpreted as an operator, crew member, etc.) and performing viewpoint tracking lighting, and have recognized the following new problems.

[0008] The driver's viewpoint may shift, causing the HUD device to temporarily lose its viewpoint. In this case, if the driver's viewpoint (at least one of their eyes) moves away from a partially illuminated area, the driver may lose the ability to visually perceive the virtual image. This can cause the driver to feel abrupt or uncomfortable.

[0009] However, even if the driver's viewpoint deviates from the partial lighting area, as long as the driver is actually located within the viewpoint zone, the driver can continue to visually recognize the virtual image by projecting onto the area where the viewpoint is located.

[0010] Furthermore, even if the driver's viewpoint deviates from the partially illuminated area and the viewpoint zone, the viewpoint should return to the viewpoint zone later. However, the viewpoint may not necessarily return to its original position. It is also conceivable that the viewpoint may return to a position quite far from its original position for some reason.

[0011] Furthermore, even when returning to a position near the original location, the viewpoint may continue to move by trial and error, gradually stabilizing the viewpoint position and eventually coming to rest. If, during the trial and error movement of the viewpoint, the viewpoint position falls outside the original partially illuminated area, light will not be projected at the viewpoint during the return, resulting in a state where the virtual image cannot be visually recognized.

[0012] However, the viewpoint returning to the viewpoint area means that the viewpoint is located within the viewpoint area. If the lighting can be considered and projected onto the viewpoint (illuminated with illumination light), a virtual image may be visually recognized.

[0013] Viewpoint loss may occur when the viewpoint moves significantly for some reason, or may occur when the viewpoint moves at a relatively short distance and at high speed.

[0014] Even if total viewpoint loss occurs, there are various ways in which this occurs, and it is important to take measures that take viewpoint loss into account as needed.

[0015] Furthermore, in recent years, HUD devices have been developed that can display virtual images over a relatively wide area in front of the vehicle. These HUD devices tend to be larger. To save energy, it's preferable to reduce the area of ​​the partially illuminated area. However, this increases the likelihood that the driver (user) will lose visibility of the virtual image if their viewpoint is lost. Consequently, achieving both improved energy efficiency and improved visibility is difficult.

[0016] Thus, there is room for improvement in viewpoint tracking lighting, but Patent Document 1 mentioned above does not describe this at all.

[0017] One of the purposes of the present invention is to suppress the loss of visibility of virtual images when viewpoint loss occurs during viewpoint tracking lighting control for illuminating a portion of a viewpoint area according to the driver's viewpoint position, thereby reducing discomfort.

[0018] Other objects of the present invention will become apparent to those skilled in the art by referring to the following exemplary embodiments and preferred embodiments and the accompanying drawings.

[0019] For example, one of the other purposes of the present invention is to prevent the virtual image from being lost not only when viewpoint loss occurs, but also when the state becomes prone to viewpoint loss, or to suppress the degradation of the virtual image quality caused by improper illumination of the viewpoint by display light, thereby not reducing the discomfort.

[0020] Means for solving problems

[0021] Hereinafter, in order to facilitate understanding of the outline of the present invention, embodiments according to the present invention are exemplified.

[0022] In a first embodiment, a head-up display device is a head-up display (HUD) device mounted on a vehicle and allowing a virtual image to be visually recognized, and includes:

[0023] a display unit that displays the image; and

[0024] a control unit that performs viewpoint tracking lighting control for illuminating a portion of the viewpoint area with light according to the viewpoint position of the driver;

[0025] The control unit performs control in the following manner:

[0026] When viewpoint loss occurs in which the viewpoint position cannot be detected, the area of ​​pixels or light sources in the display unit that contribute to the display of the virtual image is expanded, and an illumination area that is wider than a partial illumination area of ​​the viewpoint area and that was illuminated immediately before the viewpoint loss is illuminated.

[0027] In the first embodiment, when viewpoint position tracking lighting is performed and the viewpoint position is lost (viewpoint loss), control is performed to illuminate a wider illumination area than the partial illumination area that was lit (partially illuminated) before the viewpoint loss.

[0028] For example, when the viewpoint is lost, the lighting area may be expanded to the entire area (entire surface) of the viewpoint region.

[0029] When a display unit that displays an image comprises pixels formed of self-luminous elements such as LEDs and organic ELs, the illumination area can be expanded by controlling the illumination state of the pixels. Furthermore, when the display unit is a translucent display unit that combines a liquid crystal panel and a backlight (light source), the illumination area can be expanded by controlling the illumination state (on, off, etc.) of the light source (light source element). In other words, for example, by switching pixels (non-luminous pixels) surrounding the pixel that emitted light immediately before viewpoint loss to an illumination state (a state that can contribute to the visual recognition of a virtual image), the illumination area can be expanded around the illumination area immediately before viewpoint loss.

[0030] Here, "expansion based on the illumination area immediately before the viewpoint is lost" is preferred. This is because if the viewpoint is lost for a short time, the viewpoint is more likely to remain near the original illumination area, and by expanding to the vicinity of the original area, the possibility of being able to project onto the viewpoint increases.

[0031] As the viewpoint (at least one of the left and right eyes) moves, even when the viewpoint is temporarily lost, the driver (user) can still visually recognize the display (virtual image) as long as the viewpoint is within the expanded lighting area, thereby preventing the display from suddenly disappearing. This reduces discomfort. Furthermore, the likelihood of visually recognizing the desired display during vehicle operation is increased, thereby improving safety reliability.

[0032] In addition, this method can be applied to both types of HUDs: a monocular HUD that projects the same image to each of the driver's eyes, and a binocular HUD (parallax, hologram, or optical reproduction) that projects a different image (parallax image) to each eye.

[0033] In addition, as the “viewpoint loss” in this embodiment, two types of viewpoint loss are conceivable: viewpoint loss in which at least one of the two eyes is within the viewpoint area, and viewpoint loss in which the two eyes are outside the viewpoint area.

[0034] In a second aspect subordinate to the first aspect, it may be that

[0035] The control unit performs at least one of control to continuously expand the illumination area or control to expand the illumination area in stages.

[0036] According to the second aspect, by gradually expanding the illumination area, it is possible to suppress the discomfort that would otherwise be felt if the illumination area were expanded all over the viewpoint area at once. In other words, it is possible to perform "lighting expansion control" with less discomfort.

[0037] If the lighting area is expanded continuously over time, the discomfort can be further reduced. Furthermore, if the lighting area is expanded in stages (in steps), regular and efficient expansion can be easily implemented (with minimal burden on the device) according to a prescribed expansion algorithm. Furthermore, by combining continuous and staged expansion, the lighting area can be expanded with greater freedom.

[0038] In a third aspect dependent on the second aspect, it may be that

[0039] The control unit performs control to illuminate the entire viewpoint area when the viewpoint loss continues for a first predetermined time or longer.

[0040] When the illumination area of ​​a portion of the viewpoint area is expanded, a portion of the light beam directed toward the expanded illumination area may enter the original illumination area. As described in the first embodiment, the entire viewpoint area can also be illuminated at once. However, in this case, the brightness of the image (virtual image) perceived in the original illumination area may increase dramatically, potentially causing discomfort to the driver (user) due to the brightness change.

[0041] Therefore, in this method, the control of expanding the lighting range to the entire area is implemented under the condition that the first predetermined time has passed. As a result, the size of the partial lighting area can be gradually expanded before the first predetermined time has passed. Therefore, the discomfort can be suppressed (reduced).

[0042] In a fourth aspect subordinate to the second or third aspect, it may be that

[0043] The control unit performs control to increase the light intensity of the illumination light when the illumination area is expanded continuously or stepwise.

[0044] In this aspect, when expanding the illumination area, the light quantity of the light source in the direction of expanding the illumination area is controlled (gradually increased to a desired brightness), thereby further suppressing the sense of discomfort.

[0045] For example, let's define the illuminated area (partially illuminated area) immediately before the viewpoint is lost as A, and the expanded area as B. It's also possible to instantly increase the brightness of area B to the same level as area A. However, in this case, as in the third embodiment described above, it's undeniable that the brightness variation in the peripheral field of view increases to a certain extent. In this case, the driver (user) may experience discomfort.

[0046] Therefore, in this method, instead of switching the display unit's pixels (display pixels) between on and off at a desired brightness (two-variable control of lighting / extinguishing), control is implemented to increase the brightness to the desired level over time (in other words, multivariable lighting control). This can further reduce discomfort.

[0047] In a fifth aspect belonging to any one of the second to fourth aspects, it may be that

[0048] The control unit implements the following control: when continuously or stage-by-stage expanding the lighting area, the direction in which the viewpoint loss occurs is estimated or predicted based on at least one of the movement direction of the viewpoint before the viewpoint loss, past learning results related to the movement of the viewpoint, and the driving conditions when the viewpoint is lost, and the lighting area is expanded in a manner that at least includes the estimated or predicted direction.

[0049] In this method, the direction in which viewpoint loss occurs (the direction in which the viewpoint moves when viewpoint loss occurs) is estimated or predicted, and the illumination area is expanded using the contents of the estimation (prediction).

[0050] Even when viewpoints are lost, the direction of viewpoint movement can sometimes be estimated (or predicted). For example, when only one of the two eyes is lost, the direction of viewpoint loss can be estimated (or predicted) by tracking the movement of the remaining eye (based on the estimation of the viewpoint movement direction).

[0051] In addition, for drivers (users), there are personal characteristics in the process and actions during driving. For example, a driver frequently changes his posture while driving. Therefore, if it is known through past learning that the viewpoint sometimes changes up and down (in the height direction of the vehicle), the learning results can be effectively utilized to infer (predict) that the viewpoint moves in the up and down direction and causes viewpoint loss (inference or prediction based on learning).

[0052] In addition, when the vehicle is currently traveling on a bumpy road (unpaved road, etc.) (for example, this can be determined based on vehicle information collected by the ECU, etc.), it is possible to infer (predict) that the viewpoint may be lost due to instantaneous movement in the up and down or tilted direction (inference or prediction based on driving conditions).

[0053] By performing such an estimation (prediction) and expanding in a manner that includes the estimated (predicted) direction, efficient expansion can be achieved. For example, by expanding the estimated (predicted) direction more significantly (increasing the degree of expansion) than the non-estimated (non-predicted) direction, the likelihood of projecting an image in the lost viewpoint is increased. The expansion of the illumination area can effectively enhance the visual recognition of the virtual image. Furthermore, by enabling focused illumination of the required areas, energy savings are also achieved.

[0054] In a sixth aspect belonging to any one of the second to fifth aspects, it may be that:

[0055] The viewpoint area has a prescribed shape,

[0056] When the control unit continuously or stage-by-stage expands the illumination area, the control unit implements any one of the following expansions:

[0057] isotropic expansion to uniformly expand the illumination area around the illumination area;

[0058] Alternatively, anisotropic expansion is performed to expand the illumination area unevenly around the illumination area;

[0059] Alternatively, based on a combination of the isotropic expansion and the anisotropic expansion,

[0060] When the viewpoint position is detected again while the expansion is being performed, or when the illumination area is expanded to the entire area of ​​the viewpoint zone, control is performed to end the expansion.

[0061] In the sixth aspect, the viewpoint area and the outer contour (outline) of the illumination area have predetermined shapes. When expanding the illumination area, any of isotropic expansion, anisotropic expansion, or a combination of these can be implemented. Furthermore, "uniformly expanding the illumination area to its surroundings" can also be understood as "expanding to a larger area with a shape similar to the original shape of the illumination area." Furthermore, "non-uniformly expanding to its surroundings" can also be understood as "expanding to a larger area with a shape not similar to the original shape of the illumination area."

[0062] When the edge of the outline of the illumination area reaches the edge of the viewpoint zone, further expansion is impossible. Therefore, expansion is performed on other unreached edges. When the viewpoint is detected again during expansion or the entire viewpoint zone is expanded, expansion is terminated.

[0063] According to this aspect, it is possible to obtain effects such as the rules for expansion being clarified and control by software being facilitated.

[0064] In a seventh aspect belonging to any one of the first to sixth aspects, it may be that:

[0065] The control unit implements the following control: when the viewpoint position is detected again after the viewpoint loss occurs, the wide lighting area expanded after the viewpoint loss is reduced to a narrow lighting area corresponding to the re-detected viewpoint position and having the same size as the partial lighting area before the viewpoint loss.

[0066] According to the seventh aspect, when recovering from viewpoint loss, the lighting state can be restored to the same (normal) state as before the loss without causing discomfort.

[0067] In an eighth aspect dependent on the sixth aspect, it may be that

[0068] The viewpoint area has a prescribed shape,

[0069] The control unit controls, when the viewpoint position is detected again after the viewpoint loss occurs, to reduce the wide illumination area that was extended after the viewpoint loss to a narrow illumination area corresponding to the re-detected viewpoint position and having the same size as the partial illumination area before the viewpoint loss.

[0070] Furthermore, when the lighting area is reduced,

[0071] The control is performed by combining isotropic reduction for uniformly reducing the illumination area and anisotropic reduction for non-uniformly reducing the illumination area to restore the illumination area to a narrow illumination area of ​​the same size as the partial illumination area before the viewpoint was lost.

[0072] or,

[0073] The control is performed as follows: when the contraction along one of the two orthogonal line segments is set as vertical contraction and the contraction along the other is set as horizontal contraction, the vertical contraction is performed, and then the horizontal contraction is performed to restore the narrow illumination area to the same size as the partial illumination area before the viewpoint is lost,

[0074] or,

[0075] The following control is performed: horizontal contraction is performed, and then vertical contraction is performed, so that the narrow illumination area is restored to the same size as the partial illumination area before the viewpoint is lost.

[0076] In the eighth method, when the outer shape (contour) of the viewpoint area and the lighting area is set to a prescribed outer shape, such as a rectangle (including a square and a rectangle), when reducing the lighting area, any one of the first method of anisotropic reduction after isotropic reduction, the second method of horizontal reduction after vertical reduction, and the third method of vertical reduction after horizontal reduction can be adopted.

[0077] According to the eighth aspect, there are effects such as the rules for reduction being clarified and control by software being facilitated.

[0078] In a ninth aspect subordinate to the seventh or eighth aspect, it may be that

[0079] The control unit controls the time required for the wide illumination area to become the narrow illumination area to be equal to or longer than a second predetermined time.

[0080] When the viewpoint is detected again, the partial lighting is switched to the position of the viewpoint detected again (in principle, the partial lighting is the same size as the partial lighting area before the viewpoint was lost). However, the viewpoint of the driver (user) may converge to a certain position while repeatedly moving to a certain extent.

[0081] Therefore, in the ninth aspect, the normal lighting state is restored after a predetermined time has passed (after the time required for the viewpoint to stabilize has passed). This allows the viewpoint to be slightly moved during the return process, thereby suppressing (reducing) the possibility of the viewpoint drifting out of the illuminated area.

[0082] In a tenth aspect belonging to any one of the seventh to ninth aspects, it may be that

[0083] The control unit performs control to reduce the amount of illumination light when narrowing the wide illumination area to the narrow illumination area.

[0084] According to the tenth aspect, by gradually reducing the light quantity (illumination brightness) of the illumination light when narrowing the illumination area, it is possible to suppress (reduce) the discomfort that may be caused by a sudden switch to normal lighting.

[0085] In an eleventh aspect subordinate to the tenth aspect, it may be that

[0086] When the control unit reduces the amount of illumination light when narrowing the wide illumination area to the narrow illumination area,

[0087] The luminance of pixels or light source elements that have little influence on the luminance perceived at the viewpoint position is reduced over time, thereby reducing the illumination light.

[0088] The eleventh aspect shows an example of a control method based on the premise that light from a plurality of pixels travels toward one viewpoint.

[0089] When the illumination range is changed from an expanded range to a reduced range, for example, by gradually (taking time) reducing the brightness of the light source (here, C2, C3, etc. other than the light source element C1) that has little influence on the brightness of the virtual image visually recognized by the eye position (set as X1), the reduction in the brightness of the image caused by some light (light from light sources C2, C3, etc.) reaching the eye position X1 can be made less noticeable, thereby reducing discomfort.

[0090] In a twelfth aspect belonging to any one of the seventh to ninth aspects, it may be that

[0091] When the control unit reduces the wide illumination area to the narrow illumination area,

[0092] The brightness of pixels or light source elements having a small influence on the brightness viewed at the viewpoint position is reduced over time, and the brightness of pixels or light source elements having a large influence on the brightness viewed at the viewpoint position is increased over time.

[0093] The twelfth embodiment shows another example of a control method based on the premise that light from a plurality of pixels is directed toward one viewpoint.

[0094] In this method, when the illumination range is changed from an expanded range to a reduced range, for example, the brightness of the light source (here, C2, C3, etc. other than the light source element C1) that has little influence on the brightness of the virtual image visually recognized by the eye position (set as X1) is gradually reduced (taking time), and the brightness of the light source C1 that has a large influence on the brightness of the virtual image visually recognized by the eye position X1 is gradually increased (taking time).

[0095] This allows the brightness of the image (virtual image) to be maintained substantially constant even while the illumination range is changing. Therefore, for example, when the illumination range is expanded or reduced, the change in brightness (difference in brightness) of the image (virtual image) observed from eye position X1 can be reduced. This further reduces discomfort.

[0096] In a thirteenth aspect dependent on the third aspect, it may be that

[0097] The control unit variably controls the first prescribed time based on at least one of a driving condition of the vehicle, a surrounding environment, and a condition of a driver.

[0098] In the thirteenth aspect, the time required to expand the illumination area to the entire area (maximum area) of the viewpoint zone is variably controlled according to various factors, thereby implementing control suitable for the driving scene.

[0099] For example, when it is determined that the vehicle is traveling on a road with many bumps and the frequency of vehicle pitching is greater than a predetermined value, when it is determined that the driver is highly fatigued, or when the contrast of an image captured by a camera is less than a predetermined value, it is preferable to shorten the first predetermined time so that the expansion speed to the maximum area is increased compared to normal conditions (control is performed so that the maximum area is reached earlier). In these cases, it is also desirable for the driver (user) to reliably visually recognize the display (virtual image) from a safety perspective.

[0100] Furthermore, for example, at night, because the human eye is more sensitive than during the day, a more gradual expansion control over a longer period of time can be implemented to reduce discomfort. Furthermore, in situations where light and dark change dramatically, such as in tunnels, the speed at which the illuminated area expands can be increased to reach its maximum area sooner. This is because the display (virtual image) is more difficult to visually discern on rainy days than on sunny days. Therefore, it is preferable to increase the speed at which the illuminated area expands when there is a loss of vision (or loss of vision) to ensure reliable visual recognition of the display, rather than causing discomfort caused by changes in display brightness.

[0101] As described above, according to the thirteenth aspect, it is possible to implement optimal control in response to various situations.

[0102] In a fourteenth aspect dependent on the ninth aspect, it may be that

[0103] The control unit variably controls the second predetermined time based on at least one of a driving condition of the vehicle, a surrounding environment, and a condition of a driver.

[0104] Even when the illumination area is narrowed, the same effects can be obtained by performing the same control as that described in the thirteenth aspect.

[0105] In a fifteenth aspect belonging to any one of the first to fourth aspects, it may be that

[0106] The control unit controls the light quantity distribution of the illumination light in the illumination area (including the wide illumination area and the narrow illumination area) in the following manner:

[0107] The light intensity at the peripheral portion of the illumination area is controlled to be less than that at the central portion, but to be sufficient to ensure brightness exceeding a predetermined value.

[0108] or,

[0109] The light quantity is made uniform in the illumination area.

[0110] The fifteenth aspect shows a preferred example of the distribution of light intensity (brightness) in an illuminated area (including a partially illuminated area). If the viewpoint appears from a partially illuminated area (a lit area), the brightness becomes extremely low, and it is expected that the visibility of the image (virtual image) will be extremely sharply reduced.

[0111] In this case, it is desirable to reduce the discomfort felt by the viewer due to the disappearance of the virtual image (extreme reduction in brightness) when the eye (viewpoint) reaches the boundary (edge) between the partially illuminated area and the non-illuminated area.

[0112] Therefore, in a preferred example, if a rectangular illumination area is present, the light intensity is high in the center and low in the periphery (near the boundary). However, by ensuring a certain level of light intensity (brightness) (above a predetermined value), the low light intensity is used to prevent the virtual image from suddenly becoming obscured when the viewpoint extends outward from the boundary. In this case, when the viewpoint moves outward from the boundary, the image disappears after a faint virtual image is observed, thus minimizing discomfort.

[0113] In another preferred embodiment, uniform (including substantially uniform) light is applied to the illumination area (illuminated area) at a predetermined brightness level. In this case, the light intensity decreases near the edge (near the boundary), but a certain level of light intensity is maintained. Therefore, when the viewpoint moves outside the boundary, the afterimage disappears after observing a faint virtual image, which is less likely to cause discomfort.

[0114] As described above, according to the fifteenth aspect, when the viewpoint is outside the illumination area, the uncomfortable feeling caused by the sudden disappearance of the display (virtual image) can be reduced.

[0115] It will be readily apparent to those skilled in the art that further modifications may be made to the embodiments of the present invention as illustrated without departing from the spirit of the present invention.

[0116] For example, the present invention can prevent virtual images from becoming unobservable or reduce the quality of virtual images due to improper illumination of the viewpoint by display light, not only when viewpoint loss occurs, but also when the state is prone to viewpoint loss, thereby reducing discomfort.

[0117] In a sixteenth aspect of the present invention, a head-up display device is a head-up display (HUD) device mounted on a vehicle and allowing a virtual image to be visually recognized, and includes:

[0118] a display unit that displays the image; and

[0119] a control unit that performs viewpoint tracking lighting control for illuminating a portion of the viewpoint area with light according to the viewpoint position of the driver;

[0120] The control unit performs control in the following manner:

[0121] When a state in which the viewpoint position cannot be detected and viewpoint loss is likely to occur is detected, the area of ​​pixels or light sources in the display unit that contribute to the display of the virtual image is expanded, and an illumination area that is wider than a partial illumination area of ​​the viewpoint area and is illuminated immediately before the expansion is illuminated.

[0122] According to the sixteenth aspect, it is possible to detect a state where view loss is likely to occur, or to implement measures to prevent the display image from being observable (virtual image, etc.) or display quality from being degraded by predicting the actual occurrence of view loss.

[0123] In the seventeenth aspect dependent on the sixteenth aspect, it may be that

[0124] The control unit determines that the viewpoint loss is likely to occur when the moving speed of the viewpoint is equal to or greater than a first threshold value.

[0125] In the seventeenth embodiment, if the viewpoint (eye) position moves at a high speed exceeding a threshold, it is determined that viewpoint loss is likely to occur, and countermeasures are implemented. For example, such a situation is likely to occur if the driver's face suddenly and significantly shakes. This embodiment can quickly and reliably respond to such situations.

[0126] In the eighteenth embodiment dependent on the sixteenth embodiment, it may be that

[0127] The control unit determines that the state is likely to cause the view loss when at least one of the following conditions occurs:

[0128] detecting a sudden change in brightness of the surrounding area including the front of the vehicle, or predicting the sudden change;

[0129] as well as,

[0130] detecting a sudden change in brightness inside the vehicle, or predicting the sudden change;

[0131] as well as,

[0132] A rear seat monitor or a child safety monitor provided in the vehicle is turned on or is in the turned-on state;

[0133] as well as,

[0134] It is determined that the driving environment of the vehicle is an environment in which the fluctuation of the position of the driver's face or eyes increases.

[0135] The eighteenth aspect enables proactive countermeasures to various driving situations that are prone to causing loss of perspective. For example, sudden changes in brightness are likely to occur when a vehicle enters or exits a tunnel. Such sudden changes in brightness can cause drivers to close their eyes or look away, potentially leading to loss of perspective.

[0136] Furthermore, when highly directional light from oncoming vehicle headlights or LED streetlights enters the vehicle, the brightness inside the vehicle can change dramatically, which can also cause loss of perspective.

[0137] Furthermore, when the rear seat monitor or the child safety monitor is turned on, the driver often looks toward the monitoring terminal, which may cause loss of viewpoint.

[0138] In addition, when a vehicle is traveling on a road with poor road conditions, for example, on a bumpy road, on a muddy unpaved road, or on a road with a series of sharp turns, it is easy to cause loss of viewpoint due to shaking of the body or face.

[0139] According to this aspect, it is possible to implement a countermeasure against loss of viewpoint in various driving scenarios.

[0140] In a nineteenth aspect belonging to any one of the sixteenth to eighteenth aspects, it may be that:

[0141] The expansion of the lighting area includes a multi-stage expansion process.

[0142] This can reduce the driver's discomfort and also reduce the burden on the device.

[0143] In the nineteenth aspect belonging to any one of the sixteenth to twentieth aspects, it may be that

[0144] The control unit performs control to reduce the expanded wide illumination area to a narrow illumination area having the same size as the partial illumination area before the expansion when the state in which the viewpoint loss is likely to occur is resolved.

[0145] According to the nineteenth aspect, when the state with a high possibility of viewpoint loss is resolved, the illumination area is reduced. This can, for example, suppress the temperature rise of the light source and reduce the driving power of the light source.

[0146] In the twenty-first aspect dependent on the seventeenth aspect, it may be that

[0147] When the moving speed of the viewpoint is less than the first threshold, the control unit

[0148] or,

[0149] When the value becomes smaller than the first threshold or becomes smaller than the second threshold,

[0150] The following control is performed: the expanded wide illumination area is reduced to a narrow illumination area of ​​the same size as the partial illumination area before the expansion.

[0151] In the twenty-first aspect, when the necessity of expanding the illumination area is determined based on the comparison result of the viewpoint movement speed with the first threshold, the necessity of reducing the illumination area is also determined by comparing the viewpoint movement speed with the first threshold or a second threshold different from the first threshold. Since the determination is made by comparison, it is easy to implement.

[0152] The second threshold can be lower than the first threshold. In this case, if the viewpoint's movement speed is lower than the first threshold but not lower than the second threshold, the illumination area is not determined to need to be reduced. Therefore, the expanded illumination area can be stably maintained. This reduces the probability of the viewpoint straying from the illumination range.

[0153] Alternatively, the second threshold value may be greater than the first threshold value. In this case, when the viewpoint's moving speed falls below the second threshold value, it is determined that the illumination area needs to be reduced. This shortens the period during which the illumination area is expanded, thereby achieving effects such as suppressing the temperature rise of the light source and reducing power consumption.

[0154] In the twenty-second embodiment dependent on the twentieth or twenty-first embodiment, it may be that

[0155] The reduction of the illumination area includes a multi-stage reduction process, thereby alleviating the driver's discomfort.

[0156] In a twenty-third aspect, a display control device includes the control unit according to any one of the sixteenth to twenty-first aspects.

[0157] According to the twenty-third aspect, a control unit capable of taking measures against viewpoint loss can be included in the display control device, thereby improving, for example, the portability and ease of installation of the control unit.

[0158] In the twenty-fourth aspect, the display control method includes:

[0159] A step of performing viewpoint tracking lighting control to illuminate a portion of the viewpoint area according to the driver's viewpoint position;

[0160] When viewpoint loss occurs and the viewpoint position cannot be detected, or when a state in which viewpoint loss is likely to occur is detected, the process of expanding an area of ​​pixels or light sources that contribute to image display, and illuminating an illumination area that is wider than the partial illumination area of ​​the viewpoint area illuminated immediately before the expansion; and

[0161] The process of reducing the expanded wide illumination area to a narrow illumination area of ​​the same size as the partial illumination area before expansion when the viewpoint position is detected again after viewpoint loss occurs or when the state in which viewpoint loss is likely to occur is eliminated.

[0162] According to the twenty-fourth aspect, when viewpoint loss occurs or when viewpoint loss is likely to occur, effective countermeasures can be implemented afterward or in advance.

[0163] Brief description of the accompanying drawings

[0164] Figure 1 (A) is a diagram showing an example of the main structure of a HUD device having an overview of viewpoint tracking lighting control and a function of expanding the lighting area when viewpoint loss occurs. Figure 1 (B) is a diagram showing a state where viewpoint loss occurs.

[0165] Figure 2 (A) is a diagram showing a state where the lighting area is expanded after the viewpoint is lost. Figure 2 (B) is a diagram showing a preferred example of light intensity distribution of illumination light in the illumination area.

[0166] Figure 3 (A) and (B) are diagrams showing configuration examples of viewpoint areas used in a HUD device.

[0167] Figure 4 (A) is a diagram showing a configuration example of a stereoscopic display (3D) HUD device to which the present invention is applied. Figure 4(B) is a diagram for explaining the principle of displaying a stereoscopic image (virtual image).

[0168] Figure 5 (A) is a diagram showing the transition (change) of the viewpoint detection state with respect to the passage of time. Figure 5 (B) to (F) are diagrams showing how the illumination area expands and contracts according to the movement of the viewpoint in the viewpoint zone.

[0169] Figure 6 (A) to (H) are diagrams showing an example of expansion and contraction of the illumination area.

[0170] Figure 7 (A) to (D) are diagrams showing an example of reduction and expansion of the illumination area.

[0171] Figure 8 (A) and (B) are diagrams showing another example of viewpoint position change (also considering the case of returning from the viewpoint loss state to the viewpoint redetection state) and the expansion of the illumination area based on the estimation or prediction of viewpoint movement.

[0172] Figure 9 This is a flowchart showing an example of the operation procedure of the HUD device for implementing expansion and reduction of the illumination area.

[0173] Figure 10 This is a diagram showing an example of the structure of a HUD device.

[0174] Figure 11 It is a diagram showing a configuration example of a display unit.

[0175] Figure 12 (A) and (B) indicate the use of Figure 11 A diagram showing an overview of viewpoint tracking lighting control of a display unit is shown.

[0176] Figure 13 This is a diagram showing an example of the arrangement of the LED array in the display unit.

[0177] Figure 14 (A) is a diagram showing the illumination area in the viewpoint area before the illumination area is expanded. Figure 14 (B) is a diagram showing an example of the configuration of the illumination area in the viewpoint zone after the illumination area is expanded and a control unit that expands or reduces the illumination area.

[0178] Figure 15 (A) is a diagram showing an example of a lighting pattern of LEDs when the illumination area is expanded step by step. Figure 15 (B) is a diagram showing an example of the lighting pattern of the LEDs when the illumination area is gradually narrowed.

[0179] Figure 16This is a flowchart showing an example of the steps of expanding or reducing the lighting area.

[0180] Figure 17 This is a diagram showing another example of the configuration of the illumination area in the viewpoint zone after the illumination area is expanded, and the control unit that expands or reduces the illumination area.

[0181] Figure 18 This is a diagram showing an example of the configuration of a vehicle display system.

[0182] Figure 19 This is a diagram showing an example of the configuration of a display control device.

[0183] Figure 20 This is a diagram showing an example of expansion and contraction of the illumination area when a vehicle passes through a tunnel.

[0184] Figure 21 This is a flowchart showing another example of the procedure for expanding or reducing the lighting area. DETAILED DESCRIPTION

[0185] (First embodiment)

[0186] First, refer to Figures 1 to 9 , while explaining the countermeasures when the viewpoint is lost in the first embodiment. Figures 10 to 21 , while explaining the countermeasures for the state where viewpoint loss is likely to occur in the second embodiment.

[0187] The best embodiment described below is used to facilitate understanding of the present invention. Therefore, those skilled in the art should note that the present invention is not improperly limited by the embodiment described below.

[0188] Reference Figure 1 . Figure 1 (A) is a diagram showing an example of the main structure of a HUD device having an overview of viewpoint tracking lighting control and a function of expanding the lighting area when viewpoint loss occurs. Figure 1 (B) is a diagram showing a state where viewpoint loss occurs.

[0189] exist Figure 1 In the HUD device 1 shown in (A), the viewpoint area EB is divided into four partial areas Z10 to Z13, and the positions of the eyes (viewpoints) of the driver (user) can be detected in units of these partial areas.

[0190] exist Figure 1In (A) (and (B)), the arrangement direction of the partial areas Z10 to Z13 (left-right direction on the paper) is the X direction (the width direction of the vehicle) in the actual space as viewed from the driver of the vehicle, the direction along the vertical line on the paper is the Y direction (the height direction of the vehicle), and the Z direction is the direction along the direction of travel of the vehicle (the front-back direction or the depth direction). In addition, the actual space measured outside the vehicle as viewed from the driver is Figure 1 (A) and (B) show the space below the windshield 2.

[0191] The HUD device 1 includes a control unit 100, a display unit 145, and a reflective optical system (light-collecting optical system) 150. The configuration of each unit will be described below in order.

[0192] The control unit 100 includes a partial lighting control unit 110. The partial lighting control unit 110 includes a viewpoint position detection unit 112, a viewpoint loss detection unit 114, and a light control unit 116. In the figure, S1a and S1b represent viewpoint detection information. Furthermore, S2 represents viewpoint loss notification information (notification signal), which indicates that viewpoint loss has occurred.

[0193] The camera 90 also captures a person's (driver's) face, pupils, etc. The information S0 obtained by the capturing is supplied to the viewpoint position detection unit 112 .

[0194] In addition, the ECU (Electronic Control Unit) 160 centrally manages the vehicle electronics. The ECU 160 collects vehicle information, information about the vehicle's surroundings (surrounding information), information about the driver or other passengers' fatigue, and other information (biological information). Therefore, the ECU 160 has the function of a collection unit for various information. The various information collected in the ECU 160 is provided to the light control unit 116. Figure 1 In (A), the various information to be provided is represented by the symbol S3.

[0195] In addition, based on various information S3 provided by ECU160, the light control unit 116 can make adjustments such as adaptively changing the content of the expansion processing of the lighting area performed when the viewpoint is lost and the reduction processing of the lighting area after the viewpoint is redetected (this point will be described later).

[0196] The viewpoint position detection unit 112 detects the viewpoint position based on the imaging information (imaging signal) S0 from the camera 90 that captures the face or pupil of a person.

[0197] The viewpoint loss (viewpoint loss) detection unit 114 detects the occurrence of viewpoint loss. The light emission control unit 116 generates and outputs a light emission control signal S4 based on input signals S1a, S2, S3, etc., thereby controlling the light emission state (on / off, brightness when emitting light, etc.) of the display pixels in the display unit 145. The viewpoint loss (viewpoint loss) detection unit 114 may also be provided separately from the HUD device 1.

[0198] The display unit (display device) 145 includes a light source (backlight) 120, an optical system (first optical system) 130 for the display unit, and a liquid crystal panel 140 for displaying images. The liquid crystal panel is merely an example, and a non-self-luminous display unit using other non-self-luminous elements may also be used. Alternatively, a self-luminous display unit using LED elements or organic EL elements as pixels may also be used.

[0199] The light source 120 includes a plurality of light source elements (LED elements in this case) 120 a to 120 d mounted (arranged) in a planar pattern (matrix pattern) on a mounting surface of a substrate 121 .

[0200] Although not shown in the figure, the optical system (first optical system) 130 of the display unit is composed of a combination of multiple lenses. For example, a first field lens having a curved cross-sectional shape (e.g., an arc shape) on the light incident side and a flat cross-sectional shape on the light exiting side and a second field lens having a flat cross-sectional shape on the light incident side and a curved cross-sectional shape (e.g., an arc shape) are arranged adjacent to each other. The light emitted from the light source elements 122a to 122d is appropriately refracted by the first and second field lenses, and the liquid crystal panel 140 is illuminated from the back by this light. By controlling, for example, the twist angle of the liquid crystal element, it is possible to control the light transmittance of each pixel of the liquid crystal panel 140, control whether each pixel emits light or not, or control the intensity of the light emitted from each pixel (in other words, the luminous intensity of each pixel).

[0201] The reflecting optical system (condensing optical system) 150 functions as a second optical system. Figure 1 In (A), the reflecting optical system (light-collecting optical system) 150 is simplified, but specifically, for example, a reflecting mirror or a concave mirror (curved mirror: Figure 4 (B) is composed of symbol 171) and the like.

[0202] The light emitted from the display unit 145 travels while being reflected by a reflective mirror or the like of the reflective optical system (condensing optical system) 150. This light (display light: Figure 3 Symbol K) is the vehicle's windshield 2 (refer to Figure 3 ) is reflected and projects light toward the viewpoint area EB (viewpoints A1, A2).

[0203] exist Figure 1In (A), the viewpoint A1 (right eye) is located at the position of the partial area Z10 of the viewpoint area EB, and the viewpoint A2 (left eye) is located at the position of the partial area Z12 of the viewpoint area EB.

[0204] In addition, Figure 1 In (A), the light source elements 122b and 122d are turned on and are in a light-emitting state, while the light source elements 122a and 122c are turned off and are in a non-light-emitting state.

[0205] Light L1 (indicated by a dashed line) generated by light source element 122b is ultimately projected onto the left eye A2. Furthermore, light R1 (indicated by a solid line) generated by light source element 122d is ultimately projected onto the right eye A1. For example, when each pixel corresponding to each light source element 122a or 122d on the display surface of liquid crystal panel 140 forms an image with parallax for the right eye and the left eye, this parallax image is projected onto each of the driver's eyes A1 and A2. This allows the driver to visually perceive a three-dimensional virtual image.

[0206] Next, refer to Figure 1 (B). Figure 1 In (B), viewpoints A1 and A2 are located in partial areas Z11 and Z13. Accordingly, light source elements 122a and 122c are illuminated, while light source elements 122b and 122d are deactivated, remaining in the non-illuminating state. Light L2 (indicated by the solid line) generated by light source element 122a ultimately reaches left eye A2. Light R2 (indicated by the dashed-dotted line) generated by light source element 122c ultimately reaches right eye A1.

[0207] In this state, viewpoints A1 and A2 move in the X direction (rightward on the page), and the viewpoint position cannot be detected, resulting in viewpoint loss (viewpoint loss). In addition, during viewpoint loss, viewpoint A1' is located in the partial area Z12 of viewpoint area EB, and viewpoint A2' is located outside viewpoint area EB.

[0208] In this state, the light rays R2 and L2 are not projected onto viewpoints A1' and A2', and the driver cannot visually recognize the display (virtual image) of the HUD device 1. However, since viewpoint A1' is within viewpoint area EB, by changing the illumination range, viewpoint A1' can be illuminated and can be visually recognized.

[0209] Next, refer to Figure 2 . Figure 2 (A) is a diagram showing a state where the lighting area is expanded after the viewpoint is lost. Figure 2 (B) is a diagram showing a preferred example of light intensity distribution of illumination light in the illumination area.

[0210] Figure 2The positions of the viewpoints (viewpoints A1', A2') in (A) are different from Figure 1 (B) is the same as the state of viewpoint loss. Here, the viewpoint loss detection unit 114 detects the occurrence of viewpoint loss and sends a viewpoint loss detection signal (detection information) S2 to the light control unit 116. The light control unit 116 receives the signal and implements a lighting area expansion process as a countermeasure against viewpoint loss. In addition, the lighting area can be expanded, for example, by expanding the area of ​​pixels or light sources in the display unit 145 that contribute to the display of virtual images (in other words, controlling the area by increasing the number of pixels or light source elements in the lighting state). This can be achieved by controlling the lighting area to illuminate a wider area than the partial lighting area of ​​the viewpoint area illuminated immediately before viewpoint loss, based on the partial lighting area of ​​the viewpoint area illuminated immediately before viewpoint loss.

[0211] exist Figure 2 (A) Figure 1 The light source elements 122b and 122d that were off in (B) are now lit, and all the light source elements 122a to 122d are now lit (emitting light). Figure 1 In (B), only the light L2 and R2 are used for illumination, but Figure 2 In (A), in addition to this, illumination using the light beams L1 and R1 is also performed to expand (enlarge) the illumination range (illumination area) in the viewpoint area EB.

[0212] Focusing on the viewpoint area EB, light beam L1 is projected toward viewpoint A1' (located in partial area Z12 of the viewpoint area) after viewpoint loss. This prevents the driver from completely losing sight of the display (virtual image) of the HUD device 1. In other words, the occurrence of viewpoint loss suppresses (reduces or prevents) the possibility of a sudden complete disappearance of the display.

[0213] Next, refer to Figure 2 (B). Figure 2 (B) shows a preferred example of the distribution of light intensity (brightness) in an illuminated area (including a partially illuminated area). When the viewpoint moves away from the partially illuminated area (the lit area), the brightness becomes extremely low, and it can be expected that the visibility of the image (virtual image) will drop extremely sharply.

[0214] In this case, it is desirable to reduce the discomfort felt by the viewer due to the sudden disappearance (significant decrease in brightness) of the virtual image when the eye (viewpoint) reaches the boundary (edge) between the partially illuminated area and the non-illuminated area.

[0215] Therefore, in a preferred example, if a rectangular illumination area is provided, the light intensity is high in the center and low in the periphery (near the boundary). However, by ensuring a certain level of light intensity (brightness) (above a specified value), the low light intensity prevents the virtual image from suddenly disappearing when the viewpoint moves outward from the boundary. In this case, when the viewpoint moves outward from the boundary, a faint virtual image is observed and then disappears, thus reducing the risk of discomfort.

[0216] In another preferred embodiment, uniform (including substantially uniform) light is irradiated within the illumination area (illuminated area) to a predetermined brightness level. In this case, the light intensity also decreases near the edge (near the boundary), but a certain level of light intensity is maintained. Therefore, when the viewpoint moves outside the boundary, the afterimage disappears after observing a faint virtual image, which is less likely to cause discomfort.

[0217] Figure 2 The light intensity distributions DB1 and DB2 shown in (B) correspond to the other preferred examples described above. Furthermore, DB1 represents the light intensity distribution of the partial illumination area corresponding to partial area Z13 of the viewpoint area EB, while DB2 represents the light intensity distribution of the illumination area (the entire illumination area) when the illumination area is expanded to encompass the entire viewpoint area EB (partial areas Z10 to Z13). In either distribution, a light intensity exceeding a predetermined threshold value Lth is maintained near the internal boundary of the viewpoint area EB or the outer boundary of the viewpoint area EB itself (in other words, the periphery or edge of the illumination area).

[0218] As a result, the light overflows beyond this boundary and spreads, reducing the light intensity gradually (with a gradient) rather than abruptly. Therefore, even when the viewpoint moves beyond the boundary, the display (virtual image) fades and disappears, rather than disappearing suddenly. This suppresses (reduces) any feelings of discomfort or unease.

[0219] Thus, according to Figure 2 In the example (B), the discomfort caused by the sudden disappearance of the virtual image is reduced when the viewpoint is outside the illumination area.

[0220] Next, refer to Figure 3 . Figure 3 (A) and (B) are diagrams showing configuration examples of viewpoint areas used in a HUD device.

[0221] exist Figure 3 In (A), the viewpoint area EB is divided into a plurality of (here, nine) sub-areas Z1 to Z9, and the position of the driver's viewpoint A is detected in units of each sub-area Z1 to Z9.

[0222] From the light-collecting optical system 150 (see Figure 1 、 Figure 2) A portion of the display light K of the emitted image is reflected by the windshield 2 and enters the driver's viewpoint (eye) A. When the viewpoint A is within the viewpoint area, the driver can visually recognize the virtual image of the image.

[0223] exist Figure 3 In the example (B), image display light K is emitted from the condensing optical system 150 of the HUD device 1. A portion of this light is reflected by the windshield 2 and enters the driver's left and right viewpoints (left and right eyes) A1 and A2. When viewpoints A1 and A2 are within viewpoint area EB, the driver can visually recognize a virtual image.

[0224] Here, from the driver's viewpoints (eyes) A1 and A2, the width direction (left-right direction) of the vehicle 1 is defined as the X direction (or lateral direction), the height direction perpendicular to the X direction and along the road surface is defined as the Y direction (longitudinal direction), and the front direction (front-back direction) is defined as the Z direction. Figure 3 In (B), the viewpoint area EB is divided into eight subareas E1 to E8 by vertical boundaries. Each of these subareas E1 to E8, each having a vertically elongated rectangular shape, is adjacently arranged (aligned) in the horizontal direction (X direction). By detecting the viewpoint position using each subarea E1 to E8 as a unit (a unit of minimum resolution), the horizontal position of viewpoints A1 and A2 within the viewpoint area EB can be detected.

[0225] Furthermore, the viewpoint position information detected using the sub-areas Z1-Z9 or E1-E8 can also be used for control other than viewpoint position tracking and lighting. Furthermore, the "sub-area within the viewpoint area EB" and the "partially illuminated area" during lighting are different concepts, and their sizes are not necessarily the same.

[0226] Next, refer to Figure 4 . Figure 4 A is a diagram showing a configuration example of a stereoscopic display (3D) HUD device to which the present invention is applied. Figure 4 B is a diagram for explaining the principle of displaying a stereoscopic image (virtual image). Figure 4 In the drawings, the same reference numerals are given to the same parts as those in the above drawings.

[0227] exist Figure 4 In (A), a right-eye image (parallax image) QR and a left-eye image (parallax image) QL are displayed on the display surface 145 of a liquid crystal panel (broadly, a flat-panel display) 140. A "parallax image" is an image that reproduces the parallax (the difference in images perceived by each eye) that occurs when the left and right eyes are positioned differently.

[0228] Here, with the light-emitting side of the liquid crystal panel 140 as the front, an optical component 160 is disposed in front of the liquid crystal panel 140. This optical component 160 functions as a light-separating component and, as shown in the upper left corner, can be specifically comprised of a lenticular lens 170 or a parallax barrier 180 having slits SL. Furthermore, the parallax barrier 180 includes a plurality of slits 185a to 185n. However, these are merely examples and are not limiting.

[0229] When the light beams L10 and R10 separated by the optical member 160 having a beam splitting function (reproduced light for each eye for reproducing an image) enter the two eyes A1 and A2 located at the imaging point of the light, the person observes an apparent stereoscopic image IM at the position where convergence (intersection of light) occurs. In other words, this can also be regarded as a stereoscopic image IM being generated by the 3D display. Figure 4 In the example of (A), the angle of convergence is θc.

[0230] If used Figure 1 As described above, the control unit 100 , the light source (a backlight source such as an LED) 120 , and the optical system of the light source (a first optical system) 130 are arranged behind the liquid crystal panel 140 .

[0231] like Figure 4 As shown in FIG. 1A , the entire display surface 145 of the liquid crystal panel 140 is not illuminated. Instead, only the desired areas ZA and ZB are selectively illuminated. Reference numerals 147 and 147′ denote pixels corresponding to (the centers of) viewpoints A1 and A2. This selective illumination achieves partial illumination (lighting) of the viewpoint area EB.

[0232] Reference Figure 4 (B). Figure 4 In (B), a viewpoint area EB is set in front of the viewer (such as the driver of a vehicle), with viewpoint P(C) located at the center of viewpoint area EB. If imaginary imaging planes PS(L) and PS(R) corresponding to the left and right eyes are set in front of the windshield 2, respectively, a virtual image V(C) is located at the center of the overlapping area. The angle of convergence of virtual image V(C) is θd, and the viewer (user) perceives virtual image V(C) as a three-dimensional image.

[0233] The three-dimensional virtual image V(C) is displayed (formed) as follows. That is, the curved mirror (concave mirror, etc.) 171 included in the focusing optical system 150 of the HUD device 1 is used to make the image V(C) Figure 3The reproduced light L10 and R10 for the left and right eyes of the imaginary stereoscopic image IM generated by the 3D display shown in (A) is reflected (the number of reflections is at least 1 time), thereby being projected (projected) onto the windshield 2 as display light K. The reflected light reaches the eyes of the visual observer and is imaged in front of the windshield 2, thereby displaying (forming) a virtual image V(C).

[0234] Next, refer to Figure 5 . Figure 5 (A) is a diagram showing the transition (change) of the viewpoint detection state with respect to the passage of time. Figure 5 (B) to (F) are diagrams showing how the illumination area expands and contracts according to the movement of the viewpoint in the viewpoint zone.

[0235] exist Figure 5 In (A), the period from time t0 to t2 is the "viewpoint detection state" where the viewpoint is detected. At time t2, the viewpoint position cannot be detected, resulting in viewpoint loss (viewpoint loss). This viewpoint loss state continues until time t5. At time t5, the viewpoint is detected again, and the state returns to the viewpoint detection state.

[0236] Furthermore, as “viewpoint loss”, it is possible to assume both viewpoint loss in which at least one of the two eyes is located within the viewpoint area and viewpoint loss in which both eyes are located outside the viewpoint area.

[0237] In addition, the control of expanding or shrinking the lighting area when the viewpoint is lost, as described below, can be applied to both monocular HUDs that project the same image to the driver's two eyes, and binocular HUDs (parallax type, hologram type, or optical reproduction type) that project different images (parallax images) to each eye.

[0238] Figure 5 (B), (C), (D), (E), and (F) represent the illuminated areas of viewpoint area EB at times t1, t3, t4, t6, and t7, respectively. The illuminated areas are shown as rectangular (including square and oblong) areas Q1 to Q5 with sand patterns. Viewpoints A1 and A2 in the viewpoint detection state are indicated by solid lines, while viewpoints A1 and A2 in the viewpoint loss state are indicated by dashed lines.

[0239] exist Figure 5 In (B) (corresponding to time t1), viewpoints A1 and A2 are located near the upper right side on viewpoint area EB (here, a rectangular area in a plan view from the front is referred to as the viewpoint area).

[0240] By controlling the lighting, the image display light is irradiated (projected) onto a rectangular partial illumination area Q1 of a predetermined size, centered around the detected viewpoints A1 and A2. As the viewpoint moves, the viewpoint position is constantly detected, and the partial illumination area Q1 follows the viewpoint while maintaining its size. This is the normal lighting state.

[0241] The aforementioned “predetermined size” is defined here as the illumination size when the viewpoint position is detected and the partial illumination area does not contact the viewpoint area EB (in other words, in a normal lighting state).

[0242] exist Figure 5 In (C) (corresponding to time t3), the viewpoint is lost and the HUD device 1 cannot detect the viewpoint position. In fact, the viewpoint moves diagonally downward to the right in the viewpoint area EB. Figure 5 In (C), the size of the partially illuminated area Q2 is larger than Figure 5 The size of the partial illumination area Q1 in (A) (in other words, the size of the partial illumination area before the viewpoint is lost) is further expanded (enlarged). It expands approximately equally (isotropically) in directions perpendicular to each of the four sides that define the rectangular illumination area.

[0243] exist Figure 5 In (C), viewpoint A1 is outside the partially illuminated area Q2, but viewpoint A2 is inside Q2, allowing the image to be projected onto viewpoint A2. This prevents the driver from being completely unable to see the display (virtual image) when the viewpoint is lost.

[0244] Again, the control of extending the partial lighting area is performed by the control unit 100 described previously (specifically, the partial lighting control unit 110: see Figure 1 (A)) is carried out.

[0245] In addition, when the display unit 140 for displaying an image forms pixels using self-luminous elements such as LEDs or organic ELs, the display unit 140 controls the light emission state of the pixels. Figure 1 、 Figure 2 As in the example of a light-transmitting display device that combines a liquid crystal panel and a backlight (light source), the illumination area can be expanded by controlling the light-emitting state (e.g., lighting or extinguishing) of the light source (light source element). In other words, for example, by switching the pixels (non-luminous pixels) surrounding the pixels that emitted light immediately before the viewpoint was lost to a light-emitting state (a state that can contribute to the visual recognition of the virtual image), the illumination area can be expanded around the illumination area immediately before the viewpoint was lost.

[0246] Here, it is preferable to set "expansion based on the lighting area immediately before the viewpoint is lost". This is because if the viewpoint is lost for a short time, the viewpoint is likely to stay near the original lighting area, and by expanding to the surrounding of the original area, the possibility of projecting light to the viewpoint increases. Figure 5 In the example of (C), the time t1 immediately before the viewpoint loss occurs is Figure 5 By expanding the illumination area around the partial illumination area Q1 in (B) as the center, a larger partial illumination area Q2 is realized, and light can be projected toward the viewpoint A2 as described above.

[0247] Alternatively, it is possible to simultaneously project light onto the entire area within the partial illumination area Q2 that is exposed (expanded) from the partial illumination area Q1. However, when the partial illumination area within the viewpoint area EB is expanded, a portion of the light beam directed toward the expanded illumination area may enter the original illumination area. As described above, the entire viewpoint area can be illuminated at once. However, in this case, the brightness of the image (virtual image) perceived by the original illumination area will increase dramatically, and it cannot be said that the driver (user) will not experience discomfort due to the brightness change.

[0248] Therefore, when expanding the lighting area, the control unit 100 can perform at least one of continuous expansion control and phased expansion control, gradually expanding the lighting area over time. In this way, the discomfort that might arise from expanding the lighting area all at once to cover the entire viewpoint area can be suppressed. In other words, "lighting expansion control" with less discomfort is possible.

[0249] Continuously expanding the lighting area over time can further reduce discomfort. Furthermore, when expanding the lighting area in stages (in steps), regular and efficient expansion can be easily implemented (with less burden on the device) according to a prescribed expansion algorithm. Furthermore, by combining continuous and staged expansion, the lighting area can be expanded with greater flexibility.

[0250] In this way, even if the viewpoint (at least one of the left and right eyes) is temporarily lost due to movement, the driver (user) can still visually recognize the display (virtual image) as long as the viewpoint is within the expanded lighting area, thus preventing the display from suddenly disappearing. This reduces discomfort. Furthermore, since the likelihood of visually recognizing the required display during vehicle operation is increased, safety and reliability are also improved.

[0251] In addition, from Figure 5 (B) Jump to Figure 5In (C), for example, the light source can be controlled by two variables: off / on, so that the light source element can emit light to a predetermined light intensity at once. However, if the brightness changes greatly, it may also be assumed to be the cause of discomfort. Therefore, Figure 5 In the examples (B) and (C), the light intensity is gradually increased. Figure 5 Between (B) and (C), a hollow arrow with a front-end expansion is shown, indicating that the amount of light gradually increases (this is important for Figure 5 The same also applies to the arrows drawn between (C) and (D)).

[0252] Specifically, rather than switching the pixels (display pixels) of the display unit 140 between on and off at a desired brightness (two-variable control of on / off), control is implemented to increase the brightness to the desired brightness over time (in other words, multivariable lighting control). This can further reduce discomfort.

[0253] Then, Figure 5 (D) Explain. Figure 5 In (D), at time t4, the illumination area is expanded to the entire area on the viewpoint area EB (in the figure, the illumination area of ​​the entire area is assigned a reference numeral Q3).

[0254] In addition, Figure 5 In (D), viewpoints A1 and A2 are Figure 5 (C) The image further moves diagonally downward to the right, but is expanded to cover the entire range of the illumination area, so that the image is projected at both viewpoints A1 and A2, and the driver can visually recognize, for example, a three-dimensional image (virtual image).

[0255] Here, refer to Figure 5 (A) Time t4 is the time point after the first predetermined time Tth1 has passed since the viewpoint loss occurred at time t2. In other words, Figure 5 In (D), when the viewpoint loss continues for the first predetermined time Tth1 or longer, control is performed to illuminate the entire viewpoint area EB.

[0256] Here, as mentioned above, Figure 5 In stage (C), the lighting range can also be expanded (enlarged) to the entire area of ​​the viewpoint area EB at one go, but in this case, it can also be assumed that the brightness of the image (virtual image) observed from the original lighting area increases sharply, and it cannot be said that the driver (user) will not feel discomfort due to the change in brightness.

[0257] Therefore, in Figure 5 (B) After that, it becomes Figure 5 (C) If the viewpoint is not detected again even in this case, it becomes Figure 5(D) (the state where the illumination range is expanded to the entire area of ​​the viewpoint area). In other words, the control of expanding the illumination range to the entire area is implemented on the condition that the first predetermined time Tth1 has passed. Thus, the size of the partial illumination area can be gradually expanded (for example, Figure 5 (C)), therefore, it is possible to suppress (reduce) the discomfort.

[0258] The above describes an example of expansion control of a partially illuminated area. Specific examples of expansion and variations will be described later. Furthermore, expansion control that estimates (or predicts) the direction of viewpoint movement may also be implemented, which will also be described later.

[0259] Next, refer to Figure 5 (E), (F). Figure 5 (E) shows the state at time t6. Since the viewpoint is detected again at time t5, the illumination area is reduced to the partial illumination area Q4 so as to correspond to the position of the viewpoint detected again. However, the size of the partial illumination area Q4 is smaller than that of the partial illumination area Q4. Figure 5 The partially illuminated area Q1 of (B) is large and cannot be completely restored to its original size. In the next 5 (F), it is reduced to its original size. Figure 5 (F) shows the state at time t7.

[0260] When the viewpoint is detected again, the system switches to the partial lighting based on the detected viewpoint position (in principle, the partial lighting is the same size as the partial lighting area before the viewpoint was lost). This allows the system to return to the same (normal) lighting state as before the viewpoint was lost without any discomfort when recovering from the viewpoint loss. Figure 5 At stage (E), it is also possible to reduce it to the same size as the original partial lighting size at once.

[0261] However, the viewpoint of the driver (user) may converge to a certain position while repeatedly moving to a certain extent.

[0262] Therefore, in Figure 5 In the examples (E) and (F), the normal lighting state is restored at time t7 after the second predetermined time Tth2 has passed since the time t5 at which the viewpoint is detected again (the time required for the viewpoint to stabilize has passed). This can suppress (reduce) the viewpoint from deviating from the illumination area due to a small movement of the viewpoint on the way back. In addition, the illumination area can be gradually narrowed (for example, until the second predetermined time Tth2 has passed). Figure 5 (E)) By gradually reducing the size of the illuminated area, it is possible to suppress (reduce) the discomfort caused to the driver.

[0263] In addition, from Figure 5 (D) jumps to (E), and from Figure 5 When switching from (E) to (F), by gradually reducing the amount of lighting (brightness), it is possible to suppress (reduce) the discomfort that may be caused by a sudden switch to normal lighting. Figure 5 between (D) and (E), and Figure 5 Between (E) and (F), a thin blank arrow is shown, indicating that the light intensity gradually decreases. Other examples of narrowing the illumination area will be described later.

[0264] Next, refer to Figure 6 . Figure 6 (A) to (H) are diagrams showing an example of expansion and contraction of the lighting area. As shown in the figure, the viewpoint area EB has an outer shape of a prescribed shape (here, a square or a rectangle). However, the present invention is not limited to this. More precisely, the "viewpoint area" represents a prescribed area divided by the left-right direction (X-axis direction), the up-down direction (Y-axis direction), and the depth direction (Z-axis direction) of the vehicle interior (the shape of the above-mentioned prescribed area includes, for example, a cube, a rectangular parallelepiped, and an ellipsoid.), and is set to: be the same as the area configured for the observer's viewpoint position in the vehicle equipped with the HUD device 20 (also called the eye activity range), or include most of the above-mentioned eye activity range (for example, more than 80%). In the drawings used to illustrate this embodiment, the concept of the depth direction is omitted, and the viewpoint area is represented by a rectangle divided by the left-right direction and the up-down direction. In addition, the shape of the viewpoint area divided by the left-right direction and the up-down direction can be set to a polygon, an ellipse, etc. in addition to a quadrilateral or a rectangle (including a rectangle or a square).

[0265] First, explain Figure 6 expansion mode. When the control unit 100 (or 110) expands the illumination area continuously or in stages, for example, the control unit 100 (or 110) can perform any one of isotropic expansion that uniformly expands the illumination area around it, anisotropic expansion that unevenly expands the illumination area around it, or a combination thereof. If the illumination area EB having a square or rectangular shape is taken as an example, any one of "isotropic expansion" that expands along a perpendicular line relative to each of the four sides, "anisotropic expansion" that expands along a perpendicular line relative to each of one side, two sides, or three sides, or "expansion based on a combination of isotropic expansion and anisotropic expansion" can be implemented. In addition, when any side of the outer shape of the illumination area reaches the corresponding side of the outer shape of the viewpoint area EB, expansion of the other sides that have not been reached is implemented. When the viewpoint position is detected again during the implementation of the expansion, or when the illumination area is expanded to the entire area of ​​the viewpoint area EB, control to end the expansion can be implemented.

[0266] Figure 6 Three expansion modes are shown (at least partially different from Figure 5 A specific example). An extended pattern is extended to Figure 6 (A), (B), (E), (H) are examples. Figure 5 (B), (C), (D) (These are equivalent to Figure 6 (A), (B), (H)) Figure 6 (E) pattern.

[0267] The second expansion mode is to expand to Figure 6 (A), (C), (F), (H) mode. The third extended mode is to expand Figure 6 (A), (D), (G), and (H) modes. Efficient expansion is achieved using isotropic expansion and anisotropic expansion.

[0268] exist Figure 6 In the example, the rules for expansion are clarified, making software-based control easier.

[0269] Next, the reduction mode will be described. When reducing the illumination area, for example, the control unit 100 or 110 controls the illumination area so that, when the viewpoint position is detected again after viewpoint loss occurs, the illumination area that was wide after the viewpoint loss is reduced to a narrow illumination area corresponding to the re-detected viewpoint position and having the same size as the partial illumination area before the viewpoint loss.

[0270] At this time, any of isotropic shrinkage, which shrinks the illumination area uniformly, anisotropic shrinkage, which shrinks it unevenly, or a combination of these can be implemented. Specifically, for example, a first shrinkage mode (first method) can be assumed, which controls the illumination area having a square or rectangular shape by combining "isotropic shrinkage" (shrinking along a perpendicular line relative to each of the four sides) with "anisotropic shrinkage" (shrinking along a perpendicular line relative to each of one, two, or three sides) to restore the illumination area to a narrow size that is the same as the partial illumination area before the viewpoint was lost.

[0271] In addition, when the contraction along one of the two orthogonal line segments is set to vertical contraction and the contraction along the other is set to horizontal contraction, it is possible to restore the original lighting size by appropriately implementing these (including the case of combined implementation). In addition, as the "two orthogonal line segments", when the plane when observed ignoring the depth of the viewpoint area can be grasped as a rectangle (including a square or a rectangle) erected perpendicular to the road surface, a line segment in the height direction of the vehicle and a line segment in the width direction of the vehicle can be used. Specifically, for example, a second reduction mode can be assumed, and the two reduction modes implement the following control: when the contraction along the longitudinal side of the square or rectangle is set to vertical contraction, and the contraction along the transverse side is set to horizontal contraction, horizontal contraction is implemented, followed by vertical contraction, and a narrow lighting area is implemented to restore it to the same size as the partial lighting area before the viewpoint was lost (second method).

[0272] In addition, a third reduction mode can be assumed, which implements control such that horizontal reduction is performed, followed by vertical reduction, and a narrow illumination area is restored to the same size as the partial illumination area before the viewpoint is lost.

[0273] This makes it possible to clarify the rules for shrinking and facilitate software control.

[0274] exist Figure 6 In , three reduction modes are obtained by reversely tracking each of the three expansion modes mentioned above. In addition, Figure 6 The zoom-out mode shown is the zoom-out mode of the second and third modes mentioned above (using Figure 7 The first method of reduction mode will be described.

[0275] exist Figure 6 In the example, from Figure 6 (H) is the starting point, and can be reduced to Figure 6 (E), (B), (A) first reduction mode, reduction to Figure 6 (F), (C), (A) second reduction mode, reduce to Figure 6 Any of the third reduction modes of (G), (D), and (A).

[0276] Next, refer to Figure 7 . Figure 7 (A) to (D) are diagrams showing an example of reduction and expansion of the illumination area.

[0277] exist Figure 7 Two reduction (or expansion) modes are shown in FIG. Figure 7 The reduction patterns (A), (B), and (D) show the case where isotropic reduction is performed after anisotropic reduction. Figure 7 The reduction patterns (A), (C), and (D) represent isotropic reduction followed by anisotropic reduction. These correspond to the first reduction pattern described above. Furthermore, by backtracking each reduction pattern, two expansion patterns were obtained. These patterns are merely examples and are not intended to be limiting.

[0278] Next, refer to Figure 8 . Figure 8 (A) and (B) are diagrams showing another example of viewpoint position change (also considering the case of returning from the viewpoint loss state to the viewpoint re-detection state), and the expansion of the lighting area based on the estimation or prediction of viewpoint movement. Figure 8 In, use Figure 3 (B) The viewpoint area shown.

[0279] exist Figure 8 In (A), viewpoints A1 and A2 are initially located in partial areas W7 and W8 of the viewpoint area EB (viewpoint detection state). Then, the viewpoints move significantly to the right (positive X direction), and the viewpoint on one side (viewpoint A2) moves outside the viewpoint area EB (viewpoint movement (1)). Next, viewpoints A1 and A2 move to the left (negative X direction), and the deviated viewpoint A2 also returns to the viewpoint area EB, but the return is slightly smaller and does not return to its original position.

[0280] Furthermore, viewpoints A1 and A2 move slightly to the lower right (viewpoint movement (3)), and then return to the left side of the original position (viewpoint movement (4)).

[0281] Even in such a case, if the control of expanding the lighting area is implemented when the viewpoint is lost, the driver is more likely to be able to visually recognize the display (virtual image) based on the HUD device 1 when the viewpoint is about to return to the original position, which is also beneficial in this regard.

[0282] Furthermore, when expanding the illumination range, it is also possible to estimate or predict the direction of viewpoint movement, and perform control to further expand the illumination range in the estimated (predicted) direction (including expanding only in the estimated direction).

[0283] In other words, when the lighting area is continuously or gradually expanded, the control unit 100 (or 110) can implement the following control: when the lighting area is continuously or gradually expanded, the direction in which the viewpoint loss occurs is estimated or predicted based on at least one of the movement direction of the viewpoint before the viewpoint loss, the past learning results related to the movement of the viewpoint, and the driving conditions when the viewpoint is lost, and the lighting area is expanded in a manner that at least includes the estimated or predicted direction.

[0284] In other words, the direction in which viewpoint loss occurs (the direction in which the viewpoint moves when viewpoint loss occurs) can be estimated or predicted, and the illumination area can be expanded using the estimated (predicted) content.

[0285] Even when viewpoints are lost, the direction of viewpoint movement can sometimes be estimated (or predicted). For example, when only one of the two eyes is lost, the direction of viewpoint loss can be estimated (or predicted) by tracking the movement of the remaining eye (based on the estimation of the viewpoint movement direction).

[0286] In addition, for drivers (users), there are personal characteristics in the process and actions during driving. For example, a driver frequently changes his posture while driving. Therefore, if it is known through past learning that the viewpoint sometimes changes up and down (in the height direction of the vehicle), the learning results can be effectively utilized to infer (predict) that the viewpoint moves in the up and down direction and causes viewpoint loss (inference or prediction based on learning).

[0287] In addition, when the vehicle is currently traveling on a bumpy road (unpaved road, etc.) (for example, this can be determined based on vehicle information collected by the ECU, etc.), it is possible to infer (predict) that the viewpoint may be lost due to instantaneous movement in the up and down or tilted direction (inference or prediction based on driving conditions).

[0288] By performing such an estimation (prediction) and expanding in a manner that includes the estimated (predicted) direction, efficient expansion can be achieved. For example, by expanding the estimated (predicted) direction more significantly (increasing the degree of expansion) than the non-estimated (non-predicted) direction, the likelihood of projecting an image in the lost viewpoint is increased. The expansion of the illumination area can effectively enhance the visual recognition of the virtual image. Furthermore, by enabling focused illumination of the required areas, energy savings are also achieved.

[0289] exist Figure 8 In the example (A), initially, range F1 is illuminated. However, the above-mentioned estimation (prediction) may be performed to greatly expand the illumination area (to range F2) in the estimated (predicted) direction, i.e., the right side (positive X direction), while the illumination area may be slightly expanded (to range F3) in the left side (negative X direction).

[0290] exist Figure 8 In (A), by implementing such an expansion (extension) of the lighting area, the driver can visually recognize the display (virtual image) (or increase the chance of visual recognition) in any of the above-mentioned viewpoint movements (1), (2) or (3), (4).

[0291] Next, refer to Figure 8 (B). Figure 8 In (B), viewpoints A1 and A2 move significantly to the right (positive X direction), and each viewpoint moves outside the viewpoint area EB (viewpoint movement (5). After that, the viewpoint also moves outside the viewpoint area EB (viewpoint movement (6)). Then, they move significantly to the left (negative X direction), pass significantly through the original position, and move to a position significantly to the left of the original position (viewpoint movement (7)).

[0292] exist Figure 8 In the example of (B), the same viewpoint movement estimation (prediction) as in (8A) is performed, and the illumination range is expanded from F1 to the area including F2 and F3. However, since the viewpoint cannot be detected again even after this expansion, the illumination range is further expanded to include the area of ​​F4 (the entire area of ​​the viewpoint area EB).

[0293] exist Figure 8 In (B), by implementing such expansion (extension) of the illumination area, the driver can visually recognize the display (virtual image) (or increase the chance of visual recognition) even when the viewpoint moves (5), (6), and (7) as described above. In addition, after emphasizing the illumination of the required area, the illumination is expanded to cover the entire viewpoint area EB, which is also beneficial in terms of energy saving.

[0294] The above describes the change control of the lighting area according to the present invention through several examples, but the present invention is not limited thereto and can be variously modified and applied.

[0295] For example, when narrowing a wide lighting area to a narrow lighting area, the control unit 100 (or 110) can reduce the amount of lighting light by taking time to reduce the brightness of pixels or light source elements that have little impact on the brightness visually recognized at the viewpoint position, thereby reducing the lighting light.

[0296] This control is an example of a control method based on the premise that light from multiple pixels is directed to one viewpoint. Part of the light beam directed to the partial illumination area in the viewpoint area may also be directed to other partial illumination areas. In other words, part of the light beam directed to the partial area Z2 may enter Figure 3(A) Partial area Z5. If the pixels or light sources that primarily direct light beams to partial areas Z1, Z2, Z3, ..., and Z9 are respectively set as illumination elements C1, C2, C3, ..., and C9, then partial area Z5 is illuminated by the light beam directed from illumination element C5 and by a portion of the light beams from illumination elements C2, C4, C6, and C8 that are directed to adjacent partial areas Z2, Z4, Z6, and Z8. Therefore, when narrowing from a wide illumination area (e.g., partial areas Z2, Z4, Z5, Z6, and Z8) to a narrow illumination area (e.g., partial area Z5), if the amount of light from illumination elements C2, C4, C6, and C8 is reduced, the brightness of the image visually recognized in illumination area Z5 decreases. It is also assumed that the change (reduction) in the visually recognized brightness causes discomfort to the viewer.

[0297] Therefore, when the illumination range is changed from an expanded range to a reduced range, for example, by gradually (taking time) reducing the brightness of the light source (here, C2, C3, etc. other than the light source element C1) that has little influence on the brightness of the virtual image visually recognized by the position of the eye (set as partial area X1), the reduction in the brightness of the image caused by some light (light from light sources C2, C3, etc.) reaching the position X1 of the eye can be made less noticeable, thereby reducing the discomfort.

[0298] In some embodiments, when the illumination range is changed from an expanded range to a narrowed range, for example ... Figure 3 In the example, when the brightness of a light source (here, C1, C2...C9 other than lighting element C5) that has little influence on the brightness of a virtual image visually recognized by the partial area Z5) is gradually reduced (taking time), the brightness of the light source that has less influence on the brightness of the virtual image visually recognized by the eye position (for example, lighting elements C1, C3, C7, C9 corresponding to partial areas Z1, Z3, Z7, Z9 relatively far from partial area Z5) is reduced more quickly, and the brightness of the light source that has a greater influence (for example, lighting elements C2, C4, C6, C8 corresponding to partial areas Z2, Z4, Z6, Z8 relatively close to partial area Z5) is reduced more slowly. Here, reducing the brightness quickly includes, for example, reducing the brightness gradually faster than the other side, reducing the brightness faster than the other side, or a combination thereof (not limited to these).

[0299] Furthermore, when narrowing a wide illumination area to a narrow illumination area, the control unit 100 (or 110) may spend time decreasing the brightness of pixels or light source elements that have a small impact on the brightness perceived at the viewpoint, and spend time increasing the brightness of pixels or light source elements that have a large impact on the brightness perceived at the viewpoint. This control is another example of a control method based on the premise that light from multiple pixels is directed toward a single viewpoint.

[0300] In other words, when the illumination range is changed from an expanded range to a reduced range, for example, the brightness of the light source (here, C2, C3, etc. other than the light source element C1) that has little influence on the brightness of the virtual image visually recognized by the eye position (set as partial area X1) is gradually reduced (taking time), and the brightness of the light source C1 that has a large influence on the brightness of the virtual image visually recognized by the eye position X1 is gradually increased (taking time).

[0301] This allows the brightness of the image (virtual image) to be maintained substantially constant even while the illumination range is changing. Therefore, for example, when the illumination range is expanded or reduced, the change in brightness (difference in brightness) of the image (virtual image) observed from eye position X1 can be reduced. This further reduces discomfort.

[0302] The control portion 100 (or 110) may variably control the vehicle based on at least one of the driving condition of the vehicle, the surrounding environment, and the condition of the driver. Figure 5 A shows the first predetermined time Tth1.

[0303] In other words, the time required to expand the illumination area to the entire area (maximum area) of the viewpoint zone is variably controlled according to various reasons, and control suitable for the driving scene is implemented.

[0304] For example, when it is determined that the vehicle is traveling on a road with many bumps and the frequency of vehicle pitching is greater than a predetermined value, when it is determined that the driver is highly fatigued, or when the contrast of an image captured by a camera is less than a predetermined value, it is preferable to shorten the first predetermined time Tth1 so that the expansion speed to the maximum area is increased compared to normal conditions (control is performed so that the maximum area is reached earlier). In these cases, it is also desirable for the driver (user) to reliably visually recognize the display (virtual image) from a safety perspective.

[0305] Furthermore, for example, at night, because the human eye is more sensitive than during the day, a more gradual expansion control over a longer period of time can be implemented to reduce discomfort. Furthermore, in situations where light and dark change dramatically, such as in tunnels, the speed at which the illuminated area expands can be increased to reach its maximum area sooner. This is because the display (virtual image) is more difficult to visually discern on rainy days than on sunny days. Therefore, it is preferable to increase the speed at which the illuminated area expands when there is a loss of vision (or loss of vision) to ensure reliable visual recognition of the display, rather than causing discomfort caused by changes in display brightness.

[0306] In this way, the optimal control can be implemented in response to various situations.

[0307] The control portion 100 (or 110 ) may variably control the second prescribed time Tth2 based on at least one of the driving condition of the vehicle, the surrounding environment, and the condition of the driver.

[0308] When the illumination area is narrowed, the same effects can be obtained by performing the same control as in the case of expansion.

[0309] Next, refer to Figure 9 , Figure 9 This is a flowchart showing an example of the operation procedure of the HUD device for implementing expansion and reduction of the illumination area.

[0310] During viewpoint tracking lighting control (step S1), if, for example, a viewpoint loss exceeding a threshold duration is detected (step S2), the lighting area expansion process is implemented (step S3). Furthermore, the reason for detecting "viewpoint loss exceeding a threshold duration" is that if the expansion process is implemented every time a very brief viewpoint loss occurs, it could lead to discomfort caused by brightness changes. Therefore, countermeasures are implemented targeting viewpoint loss that persists for a certain period of time.

[0311] In step S3, expansion control of the lighting area is implemented (assuming that the largest area is the entire area of ​​the viewpoint area). At this time, the expansion can also be continuous or staged. In addition, the viewpoint loss that lasts for more than the first specified time can be expanded to the entire area of ​​the viewpoint area. In addition, the amount of light can also be gradually increased. In addition, at least one of isotropic expansion, anisotropic expansion (including anisotropic expansion based on the estimation or prediction of the viewpoint loss direction) and a combination of these can also be implemented. In addition, it is also possible to perform processing different from the usual based on environmental factors (driving scene, day and night or weather, etc.) and biological state factors (driver's fatigue, etc.) (for example, variably controlling the first specified time).

[0312] In step S4, it is determined whether the viewpoint (viewpoint position) has been detected again. If not, the process returns to step S3, and if so, the process jumps to step S5.

[0313] In step S5, reduction control of the illuminated area is implemented. At this time, reduction based on a combination of isotropic and anisotropic reduction can also be implemented. Alternatively, control can be implemented to return the area to its original size after a second predetermined time has elapsed. Alternatively, the amount of light can be gradually reduced. Furthermore, different processing (for example, variably controlling the second predetermined time) can be implemented based on environmental factors (driving scene, day or night, weather, etc.) or biological state factors (driver's fatigue, etc.).

[0314] As described above, according to the present invention, when viewpoint tracking lighting control is performed to illuminate a portion of the viewpoint area according to the driver's viewpoint position, it is possible to suppress the loss of virtual image observation and reduce discomfort when viewpoint loss occurs.

[0315] (Second embodiment)

[0316] In the second embodiment, a countermeasure in a state where viewpoint loss is likely to occur will be described.

[0317] Reference Figure 10 . Figure 10 : is a diagram showing an example of the structure of a HUD device. Figure 10 In FIG, the same symbols are given to the parts that are common to the above figures. Figure 10 In FIG, the HUD device is represented by symbol 1'.

[0318] The HUD device 1 ′ includes a display unit (display device) 145 , a folding mirror (reflecting mirror) 169 , a curved mirror (concave mirror) 171 , and a light-emitting window 143 in a housing 141 . Display light is emitted toward the windshield 2 through the window 143 .

[0319] The display unit 145 includes a light source (backlight) 120, an optical system 130 for the light source, a diffuser 137, and a liquid crystal panel 149. The position of the driver's viewpoint (eye) A is captured by a camera 90 as a viewpoint detection unit. A virtual image V is displayed on a virtual image display surface PS in front of the vehicle.

[0320] Next, refer to Figure 11 . Figure 11 This figure shows an example of the structure of a display unit. Display unit 145 includes a light source substrate 121, LEDs 122 serving as light sources (light source elements), a lens 130 serving as an optical system for the light source, a diffuser 137, and a liquid crystal panel 149. On light source substrate 121, LEDs 122 are arranged in a grid pattern, forming an LED array.

[0321] Next, refer to Figure 12 . Figure 12 (A) and (B) indicate the use of Figure 11 1 is a diagram showing an overview of viewpoint tracking lighting control of a display unit shown in FIG. In the figure, x', y', and z' represent coordinates used in a head-up display device. Figure 12 (A) shows the structure viewed from the direction along the z' axis. Figure 12 (B) shows the structure viewed from the direction along the X' axis. Figure 12 In (A), LEDs 120g and 120i emit light. Figure 12 In (B), LEDs 122e, 122g, and 122f emit light. Figure 12As shown in the upper side of (A), the display light is projected to the left and right eyes A1 and A2 of the driver to realize lighting. In addition, the symbol EB represents the viewpoint area. In addition, the symbol 169 represents Figure 10 The symbol 171 represents a curved mirror such as a concave mirror. The symbol VP is Figure 10 The virtual image V is the conjugate display image.

[0322] Next, refer to Figure 13 . Figure 13 : is a diagram showing an example of the arrangement of the LED array in the display unit. Figure 13 In the embodiment, LEDs 122 are arranged in a grid pattern on a light source substrate 121 to form an LED array. Figure 13 In the example shown above, LEDs 122g and 122i emit light. The light emission of LED 122 is controlled by the light emission control unit 116 of the control unit 100. Figure 1 The structure is the same.

[0323] Next, refer to Figure 14 . Figure 14 (A) is a diagram showing the illumination area in the viewpoint area before the illumination area is expanded. Figure 14 (B) is a diagram showing an example of the configuration of the illumination area in the viewpoint zone after the illumination area is expanded and a control unit that expands or reduces the illumination area.

[0324] exist Figure 14 In (A), the viewpoint area EB is divided into a plurality of areas Z20 to Z28. The driver's left eye A1 is located in the divided area Z24. In the figure, reference numeral R100 indicates the illumination area of ​​the display light.

[0325] Next, refer to Figure 14 (B) The display control device 350 includes a control unit 100 . The control unit 100 includes a viewpoint velocity detection unit 305 , a viewpoint velocity determination unit 307 , and a light emission control unit 116 .

[0326] exist Figure 14 In (B), the viewpoint moves from the divided area Z24 of the viewpoint area EB to Z22. The viewpoint velocity detection unit 305 detects the viewpoint movement velocity vs. The viewpoint velocity determination unit 307 compares the viewpoint movement velocity vs with the first threshold value θv1 and the second threshold value θv2. This comparison and determination can be easily implemented using a simple configuration. Furthermore, it enables fast and accurate determination.

[0327] When the viewpoint movement speed vs is greater than the first threshold value θv1, the control unit 100 determines that a viewpoint loss state has occurred, which is likely to cause the viewpoint position to be undetectable, and expands the illumination area of ​​the display light via the light emission control unit 116. This situation is likely to occur if, for example, the driver's face suddenly and significantly shakes.

[0328] Thus, when a state in which a viewpoint loss is likely to occur and the viewpoint position cannot be detected is detected, the control unit 100 controls the display unit 145 to expand the area of ​​pixels or light sources that contribute to displaying a virtual image, and to illuminate the area with a wider illumination area than the partial illumination area of ​​the viewpoint area EB that was illuminated immediately before the expansion. Specifically, for example, in the LED unit described above, the illumination range is expanded by individually controlling the light emission of the LEDs.

[0329] exist Figure 14 In (B), since the viewpoint (eye) movement speed (viewpoint speed) vs is greater than the first threshold θv1, the illumination area of ​​the display light is expanded under the control of the control unit 100. The expanded illumination area 200 illuminates substantially the entire viewpoint area EB.

[0330] By expanding the illumination area of ​​the display light, the image (virtual image) becomes unobservable, or the display quality of the image (virtual image) is reduced due to the display light not properly illuminating the viewpoint (eye). In addition, because the comparison and judgment are carried out at a high speed and high precision, the illumination range can be expanded quickly and reliably.

[0331] In addition, when the moving speed vs of the viewpoint is less than the second threshold value θv2, the control unit 100 reduces the expanded illumination area R200 to the same size as the illumination area R200. Figure 14 (A) The illumination region R100 shown in FIG.

[0332] When reducing the illumination area, the viewpoint (eye) movement speed vs may be compared with the first threshold θv1, similarly to when expanding, and the illumination area may be reduced if the movement speed vs is less than the first threshold θv1. In this case, the second threshold θv2 is not required.

[0333] When using the second threshold θv2, it can be lower than the first threshold θv1. In this case, if the viewpoint's movement speed is lower than the first threshold θv1 but not lower than the second threshold θv2, it is not determined that the illumination area needs to be reduced. Therefore, the expanded illumination area can be stably maintained. This reduces the probability of the viewpoint straying from the illumination range.

[0334] Alternatively, the second threshold θv2 can be greater than the first threshold θv1. In this case, when the viewpoint's moving speed falls below the second threshold θv2, it is determined that the illumination area needs to be reduced. This shortens the period during which the illumination area is expanded, thereby achieving benefits such as suppressing the temperature rise of the light source and reducing power consumption.

[0335] Next, refer to Figure 15 . Figure 15 (A) is a diagram showing an example of a lighting pattern of LEDs when the illumination area is expanded step by step. Figure 15 (B) is a diagram showing an example of the lighting pattern of the LEDs when the illumination area is gradually narrowed.

[0336] On the light source substrate 121 , a plurality of LEDs 122 are arranged in a lattice pattern to form an LED array.

[0337] exist Figure 15 In (A), the number of illuminated LEDs 122 increases as the system transitions from state A1 to state A4. In state A1, two LEDs are illuminated. In state A2, the number of illuminated LEDs increases to nine. In state A3, the number of illuminated LEDs reaches 15. In state A3, all LEDs are illuminated. In other words, the system is fully illuminated. This achieves a gradual expansion of the illumination range.

[0338] exist Figure 15 (B), produces Figure 15 (A) The opposite lighting pattern changes: as the state transitions from state B1 to state B4, the number of lit LEDs 122 decreases, thereby achieving a step-by-step reduction in the lighting range.

[0339] In this way, the expansion of the illuminated area can also include a multi-stage reduction process. This reduces the driver's discomfort and also reduces the burden on the device.

[0340] Furthermore, the reduction of the illumination area may include a multi-stage reduction process, thereby alleviating the driver's discomfort.

[0341] Next, refer to Figure 16 . Figure 16 This is a flowchart showing an example of the steps of expanding or reducing the lighting area.

[0342] In step S100, viewpoint position information is acquired. In step S101, viewpoint velocity is detected. In step S102, it is determined whether the LED array is fully illuminated. If the answer is "yes", the process proceeds to step S103.

[0343] In step S103, it is determined that the viewpoint velocity is equal to or less than the second threshold value θv2. If "yes", in step S104, the lighting area (the number of lit LEDs) is reduced. The lighting pattern of the LED array is determined based on the detected viewpoint position.

[0344] If the answer is no, the process jumps to step S105. In step S105, all lighting states are maintained.

[0345] If the answer is "No" in step S102, the process proceeds to step S106. In step S106, it is determined whether the viewpoint velocity is greater than the first threshold value θv1. If the answer is "Yes," the process expands the illuminated area (the number of illuminated LEDs) in step S107. If the answer is "No," the current lighting state is maintained. In other words, the lighting pattern is determined based on the viewpoint position, and the LED array illuminates according to this lighting pattern, maintaining its lighting state.

[0346] Next, refer to Figure 17 . Figure 17 FIG. 1 is a diagram showing another example of the configuration of the illumination area in the viewpoint area after the illumination area is expanded, and the control unit for expanding or reducing the illumination area. Figure 17 In the embodiment, the control unit 100 includes a state determination unit 309 as a device for determining a situation where the viewpoint loss is likely to occur. Various information related to the driving situation is provided to the state determination unit 309 from, for example, the ECU 160.

[0347] The situation determination unit 309 of the control unit 100 determines that the state is likely to cause viewpoint loss when at least one of the following situations occurs: a situation where a sudden change in brightness of the surrounding area including the front of the vehicle is detected, or a situation where such a sudden change is predicted, in other words, specifically, a situation where the vehicle passes through a tunnel;

[0348] as well as,

[0349] When a sudden change in the brightness of the vehicle's interior is detected or predicted, specifically, when highly directional light from the headlights of an oncoming vehicle or from a streetlight using LEDs enters the vehicle,

[0350] as well as,

[0351] If the vehicle's rear seat monitor or child safety monitor is turned on or is in the turned-on state,

[0352] as well as,

[0353] If it is determined that the driving environment of the vehicle is an environment where the position of the driver's face or eyes is subject to increased fluctuations, specifically, if the vehicle is traveling on a bad road, the illumination area is expanded based on the determination result.

[0354] By performing such situation determination, it is possible to take measures in advance corresponding to various driving situations in which loss of perspective is likely to occur.

[0355] For example, when a vehicle enters or exits a tunnel, sudden changes in brightness are likely to occur. Such sudden changes in brightness can cause drivers to close their eyes or look away, potentially leading to vision loss.

[0356] Furthermore, sudden changes in vehicle interior brightness are likely to occur when, for example, highly directional light from oncoming vehicle headlights or highly directional light from LED streetlights enters the vehicle, which can also cause loss of perspective.

[0357] Furthermore, when the rear seat monitor or the child safety monitor is turned on, the driver often looks toward the monitoring terminal, which may cause loss of viewpoint.

[0358] In addition, when a vehicle is traveling on a road with poor road conditions, for example, on a bumpy road, on a muddy unpaved road, or on a road with a series of sharp turns, it is easy to cause loss of viewpoint due to shaking of the body or face.

[0359] according to Figure 17 The structure can implement viewpoint loss countermeasures in various driving scenarios.

[0360] Next, refer to Figure 18 . Figure 18 This is a diagram showing an example of the configuration of a vehicle display system.

[0361] The vehicle display system includes: ECU 160; antenna AN; communication unit 298; map database 306; monitoring terminal 310, which can be used for a liquid crystal display device of a rear seat monitor or a child safety monitor, etc.; an ambient brightness sensor (surrounding brightness detection unit) 312, which detects the brightness of the surroundings including the front; an interior brightness sensor (interior brightness detection unit) 314, which detects the brightness inside the vehicle; a surrounding shooting camera 316, which shoots the real scene of the surroundings including the front; a camera (viewpoint detection unit) 90, which detects the viewpoint position; and a monitoring camera 320 for a rear seat monitor or a child safety monitor, which monitors people or children sitting in the rear seat.

[0362] exist Figure 18 In the example of FIG, the driver 201 can learn the status of the child 203 sitting in the rear seat (here, the child seat) via the monitoring terminal 310.

[0363] The viewpoint shooting signal S0, various information (including vehicle speed information) S3 output from the ECU 160, the surrounding brightness detection signal S5 output from the surrounding brightness sensor 312, the interior brightness detection signal S6 output from the interior brightness sensor 314, the surrounding image information S7 output from the surrounding shooting camera 316, and the monitoring information S8 output from the monitoring camera 320 are respectively supplied to the display control device 350. Based on these various signals or information, the display control device 350 detects or predicts the occurrence of a state in which the viewpoint loss is likely to occur, and adopts Figure 14 (B) or Figure 17 Prior countermeasures shown.

[0364] Next, refer to Figure 19 . Figure 19 : is a diagram showing an example of the structure of a display control device. Figure 19 In, with Figure 1 (A) and Figure 2 The same reference numerals are assigned to the same components of the control unit shown in (A).

[0365] Figure 19 The display control device 350 and Figure 1 (A) and Figure 2 (A) has the same structure and includes a control unit 100. However, Figure 19 in Figure 1 (A) and Figure 2 The configuration of (A) is further modified by adding a viewpoint velocity detection unit 305 , a viewpoint velocity determination unit 307 , and a situation determination unit 309 .

[0366] Figure 18 The various signals (or information) S5 to S9 shown are supplied to the status determination unit 309 .

[0367] The display control device 350 can be set at Figure 10 The interior of the HUD device 1' (a device capable of displaying various images in a broad sense) is shown. However, the present invention is not limited to this.

[0368] The display control device 350 may be provided separately from the HUD device 1'. In this case, the display control device 350 and the HUD device 1' are connected to each other via wireless or wired communication means. Such modifications and applications can be made as appropriate.

[0369] Next, refer to Figure 20 . Figure 20 A diagram showing an example of the expansion and contraction of the illuminated area when a vehicle passes through a tunnel.

[0370] exist Figure 20 In the example, vehicle 401 passes through tunnel 403. The brightness state of the surroundings of vehicle 401 is "bright" from time t0 to t2, "transitioning from bright to dark" from time t2 to t3, "dark" from time t3 to t4, "transitioning from dark to bright" from time t4 to t6, and "bright" from time t6 onwards.

[0371] At time t0, tunnel 403 is detected ahead of vehicle 401. This detection can be achieved, for example, by utilizing GPS communication and map database 306. Alternatively, the presence of tunnel 403 can be detected by capturing images of the forward direction using surrounding camera 316 and performing image processing based on the captured images. Furthermore, a sudden drop in brightness within the tunnel ahead can be detected by surrounding brightness sensor 312.

[0372] Before time t0, the illumination range of the viewpoint tracking lighting is set to the normal range ( Figure 14 (A) Illumination range R100).

[0373] When the presence of the tunnel 403 is detected, the display control device 350 determines that a state likely to cause viewpoint loss is predicted, and at time t0, the illumination range is expanded (see Figure 17 The lighting range is expanded R200). The state in which the lighting range is expanded continues until time t3.

[0374] After time t3, the illumination range is reduced and returns to the normal range.

[0375] At time t4, for example, the ambient brightness sensor 312 detects a sudden increase in ambient brightness. The display control device 350 determines that a state is predicted to be prone to viewpoint loss, and expands the lighting range at time t4 (see FIG. Figure 17 The lighting range is extended to R200). The state in which the lighting range is extended continues until time t7.

[0376] After time t7, the illumination range is reduced and returns to the normal range.

[0377] In this way, before vehicle 401 enters tunnel 403, a sharp drop in ambient brightness can be predicted, and the illumination range of the viewpoint tracking lighting can be expanded. Similarly, before vehicle 401 exits tunnel 403, a sharp rise in ambient brightness can be predicted, and the illumination range of the viewpoint tracking lighting can be expanded. This effectively prevents the driver from losing visual recognition of the displayed image (virtual image) or reducing the quality of the displayed image.

[0378] Next, refer to Figure 21 . Figure 21 This is a flowchart showing another example of the sequence of expanding or reducing the lighting area. Figure 21 In, with Figure 16 Common steps are marked with the same symbols.

[0379] exist Figure 21 In the flowchart, Figure 16 Steps S101, S103, and S106 are replaced with steps S101', S103', and S106'. In S101', the situation determination unit 309 performs the situation determination. In step S103', it is determined whether the lighting range needs to be reduced. In step S106', it is determined whether the lighting range needs to be expanded. Figure 16 same.

[0380] As described above, according to the present invention, during the viewpoint tracking lighting control process in which light is directed to a portion of the viewpoint area according to the driver's viewpoint position, when viewpoint loss occurs or when the driver is in a state prone to viewpoint loss, the driver is prevented from having difficulty visually recognizing virtual images or from experiencing a reduction in the display quality of the virtual images. This can thereby reduce discomfort.

[0381] This also contributes to safe driving. In addition, the driver can always see the HUD display clearly in various driving scenarios, ensuring driving comfort.

[0382] The present invention can be used in any HUD device, either a monocular type in which display light of the same image is incident on each of the left and right eyes, or a parallax type in which images with parallax are incident on each of the left and right eyes.

[0383] In this specification, the term "vehicle" can be interpreted in a broad sense as a means of transportation. In addition, the HUD device also includes a device used as a simulator (for example, an aircraft simulator).

[0384] The present invention is not limited to the above-described exemplary embodiments, and a person skilled in the art can easily modify the above-described exemplary embodiments within the scope of the claims.

[0385] Explanation of symbols

[0386] 2: Windshield (projected part, reflective and translucent part); 90: Camera (pupil or face imaging part for viewpoint detection); 100: Control unit; 110: Partial lighting (lighting) control unit; 112: Viewpoint position detection unit; 114: Viewpoint loss detection unit; 116: Lighting control unit; 120: Light source (backlight); 121: Light source substrate; 122a to 122d: Light source elements (LED, etc.); 130: Optical system of the light source (first optical system ); 140: focusing optical system (second optical system, an optical system including a reflector for projecting an image onto a windshield, etc.); 160: ECU (electronic control unit, overall control unit, information collection unit); EB: viewpoint area; Z1~Z9, W1~W12: partial areas of the viewpoint area (divided areas); 306: map database; 305: viewpoint speed detection unit; 307: viewpoint speed determination unit; 309: status determination unit; 350: display control device.

Claims

1. A head-up display device, characterized in that: A head-up display (HUD) device mounted on a vehicle and allowing a virtual image to be visually recognized, and having: a display unit that displays the image; and a control unit that performs viewpoint tracking lighting control for illuminating a portion of the viewpoint area with light according to the viewpoint position of the driver; The control unit performs control in the following manner: When viewpoint loss occurs in which the viewpoint position cannot be detected, the area of ​​pixels or light sources in the display unit that contribute to the display of the virtual image is expanded, and an illumination area that is wider than a partial illumination area of ​​the viewpoint area and that was illuminated immediately before the viewpoint loss is illuminated.

2. The head-up display device according to claim 1, wherein: The control unit performs at least one of control to continuously expand the illumination area or control to expand the illumination area in stages.

3. The head-up display device according to claim 2, wherein: The control unit performs control to illuminate the entire viewpoint area when the viewpoint loss continues for a first predetermined time or longer.

4. The head-up display device according to claim 2, wherein: The control unit performs control to increase the light intensity of the illumination light when the illumination area is expanded continuously or stepwise.

5. The head-up display device according to claim 2, wherein: The control unit implements the following control: When the lighting area is continuously or stage-by-stage expanded, the direction in which the viewpoint loss occurs is estimated or predicted based on at least one of the movement direction of the viewpoint before the viewpoint loss, past learning results related to the movement of the viewpoint, and the driving conditions when the viewpoint is lost, and the lighting area is expanded in a manner that at least includes the estimated or predicted direction.

6. The head-up display device according to claim 2, wherein: The viewpoint area has a prescribed shape, When the control unit continuously or stage-by-stage expands the illumination area, the control unit implements any one of the following expansions: isotropic expansion to uniformly expand the illumination area around the illumination area; Alternatively, anisotropic expansion is performed to expand the illumination area unevenly around the illumination area; Alternatively, based on a combination of the isotropic expansion and the anisotropic expansion, When the viewpoint position is detected again during the expansion, or when the illumination area is expanded to the entire viewpoint area, control is performed to end the expansion.

7. The head-up display device according to claim 1, wherein: The control unit implements the following control: when the viewpoint position is detected again after the viewpoint loss occurs, the wide lighting area expanded after the viewpoint loss is reduced to a narrow lighting area corresponding to the re-detected viewpoint position and having the same size as the partial lighting area before the viewpoint loss.

8. The head-up display device according to claim 6, wherein: The viewpoint area has a prescribed shape, The control unit controls, when the viewpoint position is detected again after the viewpoint loss occurs, to reduce the wide illumination area that was extended after the viewpoint loss to a narrow illumination area corresponding to the re-detected viewpoint position and having the same size as the partial illumination area before the viewpoint loss. Furthermore, when the lighting area is reduced, The control is performed by combining isotropic reduction for uniformly reducing the illumination area and anisotropic reduction for non-uniformly reducing the illumination area to restore the illumination area to a narrow illumination area of ​​the same size as the partial illumination area before the viewpoint was lost. or, The control is performed as follows: when the contraction along one of the two orthogonal line segments is set as vertical contraction and the contraction along the other is set as horizontal contraction, the vertical contraction is performed, and then the horizontal contraction is performed to restore the narrow illumination area to the same size as the partial illumination area before the viewpoint is lost, or, The following control is performed: horizontal contraction is performed, and then vertical contraction is performed, so that the narrow illumination area is restored to the same size as the partial illumination area before the viewpoint is lost.

9. The head-up display device according to claim 7 or 8, characterized in that: The control unit controls the time required for the wide illumination area to become the narrow illumination area to be equal to or longer than a second predetermined time.

10. The head-up display device according to claim 7 or 8, characterized in that: The control unit performs control to reduce the amount of illumination light when narrowing the wide illumination area to the narrow illumination area.

11. The head-up display device according to claim 10, characterized in that: When the control unit reduces the amount of illumination light when narrowing the wide illumination area to the narrow illumination area, The luminance of pixels or light source elements that have little influence on the luminance perceived at the viewpoint position is reduced over time, thereby reducing the illumination light.

12. The head-up display device according to claim 7 or 8, characterized in that: When the control unit reduces the wide illumination area to the narrow illumination area, The brightness of pixels or light source elements having a small influence on the brightness viewed at the viewpoint position is reduced over time, and the brightness of pixels or light source elements having a large influence on the brightness viewed at the viewpoint position is increased over time.

13. The head-up display device according to claim 3, wherein: The control unit variably controls the first prescribed time based on at least one of a driving condition of the vehicle, a surrounding environment, and a condition of a driver.

14. The head-up display device according to claim 9, wherein: The control unit variably controls the second predetermined time based on at least one of a driving condition of the vehicle, a surrounding environment, and a condition of a driver.

15. The head-up display device according to claim 7 or 8, characterized in that: The control unit controls the light quantity distribution of the illumination light in the illumination area (including the wide illumination area and the narrow illumination area) in the following manner: The amount of light in the peripheral portion of the illumination area is less than that in the central portion, but is sufficient to ensure brightness exceeding a predetermined value. or, The light quantity is made uniform in the illumination area.

16. A head-up display device, characterized in that: A head-up display (HUD) device mounted on a vehicle and allowing a virtual image to be visually recognized, and having: a display unit that displays the image; and a control unit that performs viewpoint tracking lighting control for illuminating a portion of the viewpoint area with light according to the viewpoint position of the driver; The control unit performs control in the following manner: When a state in which the viewpoint position cannot be detected and viewpoint loss is likely to occur is detected, the area of ​​pixels or light sources in the display unit that contribute to the display of the virtual image is expanded, and an illumination area that is wider than a partial illumination area of ​​the viewpoint area and is illuminated immediately before the expansion is illuminated.

17. The head-up display device according to claim 16, wherein: The control unit determines that the viewpoint loss is likely to occur when the moving speed of the viewpoint is equal to or greater than a first threshold value.

18. The head-up display device according to claim 16, wherein: The control unit determines that the state is likely to cause the view loss when at least one of the following conditions occurs: detecting a sudden change in brightness of the surrounding area including the front of the vehicle, or predicting the sudden change; as well as, detecting a sudden change in brightness inside the vehicle, or predicting the sudden change; as well as, A rear seat monitor or a child safety monitor provided in the vehicle is turned on or is in the turned-on state; as well as, It is determined that the driving environment of the vehicle is an environment in which the fluctuation of the position of the driver's face or eyes increases.

19. The head-up display device according to any one of claims 16 to 18, characterized in that: The expansion of the lighting area includes a multi-stage expansion process.

20. The head-up display device according to claim 16, wherein: The control unit performs control to reduce the expanded wide illumination area to a narrow illumination area having the same size as the partial illumination area before the expansion when the state in which the viewpoint loss is likely to occur is resolved.

21. The head-up display device according to claim 17, wherein: When the moving speed of the viewpoint is less than the first threshold, the control unit or, When the value becomes smaller than the first threshold or becomes smaller than the second threshold, The following control is performed: the expanded wide illumination area is reduced to a narrow illumination area of ​​the same size as the partial illumination area before the expansion.

22. The head-up display device according to claim 20 or 21, characterized in that: The reduction of the illumination area includes a reduction process in multiple stages.

23. A display control device, characterized in that: A control unit according to claim 1 is provided.

24. A display control method, characterized in that: Include: A step of performing viewpoint tracking lighting control to illuminate a portion of the viewpoint area according to the driver's viewpoint position; A step of, when viewpoint loss occurs and the viewpoint position cannot be detected, or when a state in which viewpoint loss is likely to occur is detected, expanding an area of ​​pixels or light sources that contribute to image display, and illuminating an illumination area that is wider than a partial illumination area of ​​the viewpoint area illuminated immediately before the expansion; as well as The process of reducing the expanded wide illumination area to a narrow illumination area of ​​the same size as the partial illumination area before expansion when the viewpoint position is detected again after viewpoint loss occurs or when the state in which viewpoint loss is likely to occur is eliminated.

Images