Head-Up-Display

Abstract

Head-up display, which includes: a control unit (100) configured to determine content to be projected into a driver's field of vision and a projection position of the content, an image generation unit (110) configured to output an image according to the control of the control unit (100), and an optical system (120) configured to change the optical path of the image output by the image generation unit (110) in order to project the image to the driver's field of vision, wherein the optical system (120) splits the output image into two or more images with different projection distances and projects the images, wherein the optical system (120) comprises an aspherical mirror (121) for determining the projection distances and magnifications of the projected images, and wherein the aspheric mirror (121) is divided into two or more active regions with different aspheric coefficients, the division into the active regions being accomplished by the shape of the mirror (121).

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a head-up display (HUD) and a control method therefor, and in particular to a HUD that can form a plurality of image zones, and a control method therefor.

[0002] With the ongoing development of electronic systems, the performance and safety features of vehicles are improved, and a wide variety of features are being developed to enhance driver comfort. Head-up displays (HUDs) in vehicles, in particular, have received considerable attention.

[0003] A Head-Up Display (HUD) is a device designed to project operational information onto the windshield of a vehicle or aircraft. Originally, HUDs were introduced to ensure a pilot's forward field of vision. Later, however, HUDs were also implemented in vehicles to help reduce accidents.

[0004] A HUD for a vehicle displays various information about vehicle operation, such as arrow information for guiding along a route in conjunction with a navigation system and text information to indicate speed or similar, on the windshield or in the form of augmented reality beyond the windshield, to help the driver keep their eyes on the windshield.

[0005] Therefore, when the driver checks vehicle information, they don't need to look down at the dashboard to read the relevant information. The driver can drive and look ahead, where a HUD image is displayed. The HUD thus contributes to the driver's safety.

[0006] When the HUD was first introduced, it projected an image to a pre-defined, specific position. However, the image might not be visible if the driver's viewpoint changed, or it might restrict the driver's field of vision.

[0007] Recently, a particular focus has been placed on a Fig. The HUD shown uses a system that can control the height of a projected image in accordance with a change in the driver's viewpoint or the driver's wishes. Fig. The dotted line represents an image zone. The image zone defines the area within which an image projected by the HUD can be clearly displayed. Therefore, if the position of the projected image deviates from the image zone, the image will appear distorted. For this reason, the HUD only moves the position of the projected image within the image zone.

[0008] Generally, the size, shape, and position of the image zone are determined by an aspherical mirror contained within the HUD's optical system. These dimensions are determined by the size, installation position, curvature, and rotation angle of the aspherical mirror. Furthermore, the installation positions of the other components of the optical system are determined by the aspherical mirror's properties. Thus, the projection distance of an image projected onto the image zone can be determined by the aspherical mirror.

[0009] Prior art relating to the present invention is described in Korean patent KR 101 361 095 B1 dated February 4, 2014. DE 10 2012 206 962 A1 further describes a reflective display device in which a concave mirror is arranged within the display device. Regarding the device for displaying information in WO 2015 / 019567 A1, it is described how to display a virtual image at different positions. Regarding the head-up display in US 2012 / 0050139 A1, it is described how to display information for a driver on a windshield, wherein the information can be displayed at a high or low position on the windshield. JP 2014-026244 A describes a display device designed to display a single piece of information. US 2013 / 0265646A1 describes a HUD system with a tiltable mirror that can have either a spherically or aspherically curved surface.

[0010] However, because the conventional HUD can only form one image zone, the projection distance of a projected image cannot be changed within the image zone, although the position of the projected image can be changed.

[0011] The driver changes their focus and gaze position while driving, whereas a conventional HUD projects an image with a fixed focus distance (fixed projection distance). Therefore, the image can obstruct the driver's field of vision.

[0012] In other words, when the driver looks into the distance, their gaze is directed higher than when looking at a nearby object. Furthermore, the focal distance is greater than when looking at a nearby object. However, a conventional HUD can only adjust the position of the projected image upwards, but cannot change its focal distance. Therefore, a discrepancy can occur between the driver's focal distance and the focal distance of the projected image, potentially obstructing the driver's field of vision.

[0013] To solve this problem, two HUDs with different focus distances can be mounted in one vehicle. However, this increases installation costs and also the volume and weight of the HUD module.

[0014] The object of the present invention is to create a HUD that can realize a large number of image zones with different focus distances and can be integrated into a vehicle in a space-saving manner.

[0015] This problem is solved according to the invention by a head-up display with the features of claim 1.

[0016] Advantageous embodiments and further developments of the invention are the subject of the dependent claims. SUMMARY OF THE INVENTION

[0017] Embodiments of the present invention relate to a HUD that can form a plurality of image zones with different focus distances.

[0018] In one embodiment, a HUD may comprise: a control unit configured to determine content to be projected into a driver's field of vision and the projection position of that content; a projection unit (PGU) configured to output an image according to the control unit's settings; and an optical system configured to modify the optical path of the image output by the PGU to project the image into the driver's field of vision. The optical system may split the output image into two or more images, each with different projection distances, and project the images.

[0019] The optical system includes an aspherical mirror for determining the projection distances and magnifications of the projected images, wherein the aspherical mirror is divided into two or more active areas with different aspherical coefficients.

[0020] The optical system can include screens corresponding to two or more active areas.

[0021] The active area can include a first active area for forming an image zone in the lower part of the driver's field of vision and a second active area for forming an image zone above the image zone formed by the first active area.

[0022] The projection distance of the first active area can be smaller than the projection distance of the second active area.

[0023] The enlargement of the first active area can be greater than the enlargement of the second active area.

[0024] The magnification of the first active area and the magnification of the second active area can have different values, so that the sizes of the images seen by the driver are adjusted to the same size.

[0025] The PGU can output an image using a projection method that employs a digital micromirror device or a liquid crystal device.

[0026] The PGU can have an aperture value corresponding to the range of asphericities of the aspherical mirror.

[0027] The PGU can have an aperture value corresponding to the range of a changed projection distance.

[0028] The optical system may include a tiltable screen.

[0029] The control unit can correct an image output by the PGU in accordance with the angle of the screen.

[0030] The HUD can still include a vehicle speed sensor configured to measure the vehicle's speed. The control unit can determine the projection position of the content based on the speed measured by the vehicle speed sensor.

[0031] If the measured speed is equal to or greater than a reference speed, the control unit can control the PGU to project additional information through the first active area and driving information through the second active area. Conversely, if the measured speed is less than the reference speed, the control unit can control the PGU to project driving information through the first active area and additional information through the second active area.

[0032] The PGU can output an image using a laser scanning method.

[0033] In another embodiment, a control method for a HUD may comprise: measuring, by a control unit, the speed of a vehicle; determining, by the control unit, content to be projected into the driver's field of vision and the projection position of the content based on the measured speed; and outputting, by the control unit, an image according to the result of determining the content and the projection position of the content.

[0034] When determining the content and projection position of the content, if the measured speed is equal to or greater than a reference speed, the control unit can choose to project additional information in the lower part of the driver's field of vision and project driving information above the lower part of the driver's visible area. Conversely, if the measured speed is less than the reference speed, the control unit can choose to project the driving information in the lower part of the driver's field of vision and project the additional information above the lower part of the driver's field of vision. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a photo showing a state in which a conventional HUD projects an image. Fig. Figure 2 is a block diagram showing the configuration of a HUD according to an embodiment of the present invention. Fig. Figure 3 is a schematic view illustrating an aspherical mirror of the conventional HUD. Fig. Figure 4 is a schematic view illustrating an aspherical mirror of the HUD according to the embodiment of the present invention. Fig. Figure 5 is a photograph showing a state in which the HUD projects an image according to the embodiment of the present invention. Fig. Figure 6 is a schematic view illustrating the configuration and operation of the HUD according to the embodiment of the present invention. Fig. Figure 7 is another schematic view illustrating the configuration and operation of the HUD according to the embodiment of the present invention. Fig. Figure 8 is a schematic view illustrating an image correction operation in the HUD according to the embodiment of the present invention. Fig. Figure 9 is a flowchart that explains a control procedure of a HUD. DESCRIPTION OF SPECIFIC EXECUTION FORMS

[0035] The following section describes embodiments of the invention in detail with reference to the accompanying drawings. It should be noted that the drawings are not necessarily to scale and that line thicknesses and component sizes may be exaggerated for clarity. Furthermore, the terminology used here is defined with regard to the functions of the invention and may be substituted according to the customs of users or operators. The terminology should therefore be interpreted in the context of this description.

[0036] Fig. Figure 2 is a block diagram showing the configuration of a head-up display (HUD) according to an embodiment of the present invention. Fig. Figure 3 is a schematic view showing an aspherical mirror of a conventional HUD. Fig. Figure 4 is a schematic view showing an aspherical mirror of the HUD according to the embodiment of the present invention. Fig. Figure 5 is a photograph showing a state in which the HUD projects an image according to the embodiment of the present invention. Fig. Figure 6 is a schematic view illustrating the configuration and operation of the HUD according to the embodiment of the present invention. Fig. Figure 7 is another schematic view illustrating the configuration and operation of the HUD according to the embodiment of the present invention. Fig. Figure 8 is a schematic view illustrating an image correction operation in the HUD according to the embodiment of the present invention. With reference to Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. Section 8 below describes the embodiment of the present invention.

[0037] As in Fig. As shown in Figure 2, the HUD according to the embodiment of the present invention can include a control unit 100, an image generation unit (PGU) 110, an optical system 120, and a vehicle speed sensor 130. Furthermore, the HUD can include a distortion correction unit 101.

[0038] The PGU 110 can output an image according to the control unit 100. The control unit 100 can therefore output an image via the PGU 110 so that the image is projected into the driver's field of vision.

[0039] The optical system 120 can modify the optical path of the image output by the PGU 110 to project the image into the driver's field of vision. For example, the optical system 120 can include a variety of mirrors to reflect the image output by the PGU 110 onto the vehicle's windshield.

[0040] Furthermore, the optical system 120 can split the image output by the PGU 110 into two or more images with different projection distances. The image output by the PGU 110, which includes a screen, can thus be split by the optical system 120 into two or more images with different projection distances and then projected onto the windshield. The HUD according to the embodiment of the present invention can project two or more images with different focus distances.

[0041] Because an image output by the PGU 110 can be split into two or more images with different projection distances, the PGU 110 must establish a focus of the image even though the projection distance is changed.

[0042] For example, the PGU 110 can output an image using a laser scanning method. This means that the PGU 110 can use an image output method that can establish a focus independent of the projection distance.

[0043] In another example, the PGU 110 can use a projection method employing a digital micromirror device or a liquid crystal device. In this case, the PGU 110 can be configured to have an aperture value corresponding to the range of a changed projection distance.

[0044] Therefore, if a DLP (Digital Light Processing) projector or an LCOS (Liquid Crystal On Silicon) projector is used as the PGU 110, the PGU 110 (or the PGU 110 and the optical system 120) can be configured with an aperture corresponding to the range of the changed projection distance. Thus, even though the projection distance changes, the focus of the image can be maintained.

[0045] In other words, the depth of focus of the optical system can be determined according to the equation t = 2NC (1 + M), where t represents the depth of focus, N represents the f-number, C represents the pixel size, and M represents the magnification of an optical projection system. As indicated by the equation, the depth of focus can be increased by increasing the f-number. Thus, even though the projection distance is changed, the image cannot become blurry without losing focus. Therefore, the PGU can be configured with an f-number set to a sufficiently large value to accommodate the changed projection distance.

[0046] The vehicle speed sensor 130 can measure the vehicle's speed. For example, the vehicle speed sensor 130 can measure the vehicle's speed by detecting the rotation of a transmitting output shaft.

[0047] The optical system 120 comprises an aspherical mirror 121 for determining the projection distance and the magnification of a projected image, wherein the aspherical mirror 121 is divided into two or more active areas with different aspherical coefficients. The active area can specify a region for forming an image zone. With reference to Fig. 3, Fig. 4 to Fig. Section 5 below shows the active area in greater detail.

[0048] As in Fig. As shown in Figure 3, the aspherical mirror of the conventional HUD only forms one image zone, as in Fig. Figure 1 shows that the aspherical mirror only has one active area. As shown in Fig. As shown in Figure 4, the aspherical mirror 121 of the HUD according to the embodiment of the present invention can display a plurality of image zones as shown in Figure 4. Fig. 5 shown, because the aspherical mirror 121 is divided into a multitude of active areas.

[0049] The division of the active areas can be provided by the shape of the aspherical mirror 121 and is achieved by manufacturing the aspherical mirror 121 with different aspherical coefficients (curvatures) for the corresponding active areas. Furthermore, in accordance with the aspherical coefficients, the projection distances or magnifications of images projected onto the image zones formed by the corresponding active areas can be changed.

[0050] For example, the active area of ​​the aspherical mirror 121 can be divided into first and second active areas. The first active area forms an image zone at the bottom of the driver's field of vision (for example, a box represented by solid lines in the left photo and a box represented by dotted lines in the right photo). Fig. 5) And the second active area forms an image zone above the image zone formed by the first active area (for example, a box represented by dotted lines in the left photo and a box represented by solid lines in the right photo). Fig. 5).

[0051] The projection distance of the first active area can be smaller than the projection distance of the second active area. This means that the projection distance of the image projected onto the image zone formed by the second active area can be greater than the projection distance of the image projected onto the image zone formed by the first active area. In other words, the image zone formed by the second active area can be designed to correspond to the focus distance and field of vision of a driver looking into the distance, and the image zone formed by the first active area can be designed to correspond to the focus distance and field of vision of a driver looking at a nearby object.

[0052] The magnification of the first active area can be greater than that of the second active area. This means that the image projected onto the image zone formed by the second active area can have a greater projection distance than the image projected onto the image zone formed by the first active area. Therefore, although images of the same size are output and projected, the image projected onto the image zone formed by the second active area can appear larger from the driver's perspective than the image projected onto the image zone formed by the first active area.Therefore, the magnification of the second active area can be set smaller than the magnification of the first active area, so that the sizes of the images seen by the driver are adjusted to the same size, thus preventing the driver from getting the impression that a size difference between the content changes when the driver varies their gaze.

[0053] With reference to Fig. 6, Fig. 7 to Fig. Section 8 below describes an image projection process in greater detail.

[0054] As in Fig. As shown in Figure 6, the image output by the PGU 110 can first be transmitted to the aspherical mirror 121 via a screen 122 and a mirror. The image can then be enlarged by the aspherical mirror 121 and projected into the driver's field of vision.

[0055] Because in this embodiment the aspherical mirror 121 can be divided into two or more active areas with different projection distances, the image output by the PGU 110 can be split into two or more images with different optical paths and then transmitted to the aspherical mirror 121.

[0056] As in Fig. As shown in Figure 6, the optical system 120 can contain the screens 122 corresponding to the relevant active areas, wherein any reflective or transparent screen can be used as a screen 122.

[0057] The image output by the PGU 110 can therefore be separated into images with different optical paths by different screens 122, whereby the separated images can be reflected by the mirrors to the corresponding active areas of the aspherical mirror 121. The reflected images can be extended by the aspherical mirror 121, reflected, and projected onto the windshield. As described above, the positions and sizes of the images projected onto the corresponding active areas can differ from one another.

[0058] As in Fig. As shown in Figure 7, the screen 122 can be tilted. This means that the angle of the screen 122 can be adjusted to change the optical path of the image output by the PGU 110. When a tiltable screen 122 is used, the aspherical mirror 121 can be configured to have an asphericity that changes gradually. The aspherical mirror 121 can therefore have a variety of asphericities that differ slightly from one another.

[0059] The image output by the PGU 110 can thus be reflected by the screen 122 and the mirror onto the active area of ​​the aspherical mirror 121. The position of the image reflected onto the aspherical mirror 121 can be changed according to the angle of the screen 122. In other words, the active area onto which the image is reflected can be changed according to the angle of the screen 122. The reflected image can be extended by the aspherical mirror 121, reflected again, and projected onto the windshield. As described above, the position and size of the projected image can be changed in each of the active areas.

[0060] The angle of the screen 122 can be changed by the control unit 100 or another control device. As in Fig. As shown in Figure 7, a reflective or transparent screen can be used as screen 122.

[0061] If the screen 122 can be tilted, an actual projected image can be created as in Fig. Figure 8 shows that the image may be distorted (for example, with trapezoidal distortion). The distortion correction unit 101 of the control unit 100 can correct the image output by the PGU 110 in accordance with the angle of the screen 122 and remove the distortion of the projected image.

[0062] The tiltable screen 122 can be used not only when the PGU 110 uses a DLP projector or LCOS projector, but also when the PGU uses a laser scanning method.

[0063] As in Fig. 6, Fig. 7 to Fig. As shown in Figure 8, the optical paths of the projected images in the corresponding active areas can differ. Therefore, the focus distances of the image zones formed by the corresponding active areas can also differ. Thus, the HUD according to the embodiment of the present invention can form a plurality of image zones using a single PGU due to the configuration of the optical system 120.

[0064] The control unit 100 can control the PGU 110 in accordance with the optical system 120, enabling smooth operation of the HUD. The control unit 100 can calculate and generate the shape of an image, allowing the image to be divided into multiple screens according to the separate optical paths, and can output the generated shape via the PGU 110.

[0065] Furthermore, the control unit 100 can determine the content to be projected into the driver's field of vision and the projection position of that content. The control unit 100 can therefore determine the content to be displayed by the HUD, such as route information, vehicle speed, engine speed, and fuel level, in conjunction with various vehicle systems like a navigation system and cruise control. The control unit 100 can then determine the position to which the content is to be projected (the image zone to which the content is to be projected and the position of the content within that image zone).

[0066] For example, the control unit 100 can determine the projection position of the content based on the vehicle speed measured by the vehicle speed sensor 130. Specifically, if the measured speed is equal to or greater than a reference speed, the control unit 100 can determine to project additional information in the lower part of the driver's field of vision and to project driving information above the lower part of the driver's field of vision. If the measured speed is less than the reference speed, the control unit 100 can determine to project driving information in the lower part of the driver's field of vision and to project additional information above the lower part of the driver's field of vision.

[0067] Because the driver looks into the distance at higher vehicle speeds, the control unit 100 can project driving information onto the area the driver is looking towards and additional information onto the area the driver is not looking towards. The driving information can include vehicle-related data such as vehicle speed or symbols (such as a coolant warning), while the additional information can include content related to an additional function, such as weather information.

[0068] And because the HUD, according to the present embodiment, can form a multitude of image zones with different focus distances, the control unit 100 can determine the projection position of the content with respect to the focus distance and the driver's viewing position.

[0069] Therefore, if the measured speed is equal to or greater than the reference speed, the control unit 100 can control the PGU 110 to project the driving information through the active area with the longest projection surface. Conversely, during low-speed driving (or when the measured speed is less than the reference speed), the driver's field of vision may be wider, and their focus may be closer to the vehicle. The control unit 100 can therefore display various information through the multiple active areas.

[0070] In other words, the control unit 100 can determine the driver's focus distance and gaze position based on the vehicle's speed. Using this focus distance and gaze position, the control unit 100 can adjust the display position of key information so that the driver can quickly recognize the vehicle's main information.

[0071] Because in this embodiment the PGU 110 can output an image using the laser scanning method, the control unit 100 can enable a driver to distinguish the corresponding active zones based on the gap formed between the image zones by switching off laser diodes. Similarly, in the active area where the additional information is to be displayed, the control unit 100 can switch off the laser diodes in such a way that the image is not projected onto the corresponding image zone.

[0072] Fig. Figure 9 is a flowchart that explains a control procedure for a HUD. With reference to Fig. Section 9 below describes the control procedure according to the embodiment of the present invention.

[0073] As in Fig. As shown in Figure 9, control unit 100 can measure the vehicle's speed in step S200. Therefore, because a driver changes their gaze when the vehicle's speed increases, control unit 100 can measure the vehicle's speed to determine the display positions of the content.

[0074] Then, in step S210, control unit 100 can determine whether the speed measured in step S200 is high. For example, if the vehicle speed is equal to or greater than the reference speed, control unit 100 can determine that the vehicle speed is high.

[0075] If step S210 determines that the vehicle speed is high, the control unit 100 can output an image in step S220 such that additional information is displayed in the first active area and driving information is displayed in the second active area. Thus, because the driver looks into the distance at higher vehicle speeds, the control unit 100 can control the PGU 110 to project the driving information onto the area the driver is looking towards, and continue to control the PGU 110 to project the additional information onto the area the driver is not looking towards.

[0076] If, on the other hand, it is determined in step S210 that the vehicle speed is not high, the control unit 100 can output the image in step S230 in such a way that the driving information is displayed in the first active area and the additional information is displayed in the second area.

[0077] The HUD and the control method according to the embodiment of the present invention can thus create a multitude of image zones and adjust the projection distances of the content at the positions of the corresponding image zones, so that the driver can perceive the vehicle information with only a minimal movement of their gaze. And because the HUD and the control method can create the multitude of image zones using a single PGU and the optical system, the costs can be reduced compared to using multiple PGUs. Furthermore, the HUD and the control method can change the projection positions of the corresponding content in accordance with the vehicle's speed, so that the driver can quickly perceive the vehicle information.

[0078] Preferred embodiments of the invention have been described above by way of example, but it should be clear to the person skilled in the art that various modifications, additions and replacements can be made to them without thereby departing from the scope of the invention as defined by the following claims.

Claims

[1] Head-Up Display, which includes: a control unit (100) configured to determine content to be projected into a driver's field of vision and a projection position of the content, an image generation unit (110) configured to output an image according to the control of the control unit (100), and an optical system (120) configured to change the optical path of the image output by the image generation unit (110) in order to project the image to the driver's field of vision, wherein the optical system (120) splits the output image into two or more images with different projection distances and projects the images, wherein the optical system (120) comprises an aspherical mirror (121) for determining the projection distances and magnifications of the projected images, and wherein the aspheric mirror (121) is divided into two or more active regions with different aspheric coefficients, the division into the active regions being accomplished by the shape of the mirror (121). [2] Head-Up Display according to claim 1, wherein the active area comprises a first active area for forming an image zone in the lower part of the driver's field of vision and a second active area for forming an image zone above the image zone formed by the first active area. [3] Head-Up Display according to claim 2, wherein the projection distance of the first active area is smaller than the projection distance of the second active area. [4] Head-Up Display according to claim 2, wherein the magnification of the first active area is greater than the magnification of the second active area. [5] Head-Up Display according to claim 2, wherein the magnification of the first active area and the magnification of the second active area have different values, so that the sizes of the images seen by the driver are adjusted to the same size. [6] Head-Up Display according to any of the preceding claims, wherein the image generation unit (110) outputs an image by means of a projection method which uses a digital micromirror device or a liquid crystal device. [7] Head-Up Display according to one of the preceding claims, wherein the image generating unit (110) has an aperture number corresponding to the range of a changed projection distance. [8] Head-Up Display according to one of the preceding claims, wherein the image generating unit (110) has an aperture number corresponding to a range of the asphericities of the aspheric mirror (121). [9] Head-Up Display according to any of the preceding claims, wherein the optical system (120) comprises a tiltable screen (122). [10] Head-Up Display according to claim 9, wherein the control unit (100) is a display that is controlled by the image generator The output image of the unit (110) is corrected in accordance with an angle of the tiltable screen (122). [11] Head-Up Display according to any of the preceding claims, further comprising a vehicle speed sensor (130) configured to measure the speed of the vehicle, wherein the control unit (100) determines the projection position of the contents based on the speed measured by the vehicle speed sensor (130). [12] Head-up display according to claim 11, wherein, when the measured speed is equal to or greater than a reference speed, the control unit (100) controls the image generation unit (110) to project additional information through the first active area and to project driving information through the second active area, and when the measured speed is less than the reference speed, the control unit (100) controls the image generation unit (110) to project the driving information through the first active area and to project the additional information through the second active area. [13] Head-Up Display according to one of the preceding claims, wherein the image generation unit (110) outputs an image using a laser scanning method.

Images