Head-up display device

Abstract

To achieve downsizing of a device by reflecting a beam emitted from a light source without degrading display quality.SOLUTION: Provided is a HUD device 1 for enabling at least a real image RI to be visually recognized, and the HUD device 1 comprises a first light source 11a, a first display unit 12a for displaying the real image RI, and a reflection unit 13 for reflecting a first beam L1 representing the real image RI toward a windshield WS. The reflection unit 13 reflects the first beam L1 by a first mirror 131, a second mirror 132, and a third mirror 133 in the order stated. The first mirror 131 is located along the optical path of the first beam L1 at a position closer to an opening 17 side than the first display unit 12a and closer to the first display unit 12a side than the windshield WS and the first optical focus F1 of an image-forming optical system including the second mirror 132 and the third mirror 133. The third mirror 133 is disposed so that its position in the height direction is above the position in the height direction of the first display unit 12a.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a head-up display device that performs a desired display for a viewer.

Background Art

[0002] Conventionally, for example, a head-up display device described in Patent Document 1 is known. In this head-up display device, in a configuration in which a display image displayed on a screen is reflected by light from a display to a translucent member, by changing the front-rear positional relationship between the optical focus of the imaging optical system and the screen, a virtual image is visible outside the translucent member, and a real image is visible inside the translucent member. The display is switched between the two states.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of the above conventional head-up display device, in order for an observer to observe a real image, it is necessary to make the distance between the object to be observed and the real image imaging optical system longer than the distance between the front window, which is a reflecting member, and the real image imaging optical system. There was a problem that the housing of the head-up display device became large.

[0005] In addition, for the installation of the head-up display device, a layout design considering the structure of the vehicle body is required. However, there was a problem that the layout design became very difficult due to the increase in the size of the housing.

[0006] Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a head-up display device capable of reducing the size of the device by reflecting the light beam emitted from the light source without degrading the display quality.

Means for Solving the Problems

[0007] The present invention relates to a head-up display device 1 having an emission port 17 and emitting display light from the emission port 17 toward a light-transmitting member WS to visually recognize at least a real image RI of a display image represented by the display light. The head-up display device 1 includes a first display element, a first display unit 12a that transmits the light emitted from a first light source 11a for the real image RI and displays the real image RI of the display image, and a reflection unit 13 that reflects at least a first light beam L1 representing the real image RI displayed on the first display unit 12a toward the light-transmitting member WS. The reflection unit 13 includes a first mirror 131 that reflects the first light beam L1 toward a second mirror 132, the second mirror 132 that reflects the first light beam L1 toward a third mirror 133, and the third mirror 133 that reflects the first light beam L1 toward the emission port 17. The first mirror 131 is arranged along the optical path of the first light beam L1, on the emission port 17 side of the first display unit 12a, and on the first display unit 12a side of a first optical focus F1 of an imaging optical system including the light-transmitting member WS, the second mirror 132, and the third mirror 133. The third mirror 133 and the first display unit 12a are arranged such that at least the height-direction position of the third mirror 133 is above the height-direction position of the first display unit 12a.

Advantages of the Invention

[0008] According to the present invention, the light emitted from the light source passes through the first display unit, is reflected by the first mirror, is condensed at the first optical focus position, and is reflected by the second mirror and the third mirror and travels toward the emission port, realizing an optical path of the light beam. In the configuration for realizing this optical path of the light beam, each component can be arranged in a substantially U-shape to achieve miniaturization of the device.

[0009] In addition, by placing the first mirror on the side of the first display unit from the first optical focal position, it becomes possible to display a real image at an arbitrary position.

[0010] Furthermore, as the first optical focal position is farther from the second mirror, the real image appears to be approaching the occupant and becomes difficult to see. However, by setting the first optical focal position between the first mirror and the second mirror, the first optical focal position can be brought as close as possible to the second mirror, making it easier for the occupant to see the real image.

[0011] Moreover, when the first mirror is arranged near the first optical focal position, the size of the first mirror itself can be reduced, thereby enabling miniaturization of the device.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0013] (The first embodiment of the present invention) The head-up display device according to this embodiment (hereinafter referred to as the HUD device) will be described with reference to FIGS. 1 to 4. The HUD device 1 according to this embodiment is located in front of the occupant DR driving the vehicle C, and displays a real image RI on the vehicle interior side with the windshield WS interposed therebetween.

[0014] FIG. 1 is a diagram showing the configuration when the real image RI is displayed in the HUD device 1 according to this embodiment. In FIG. 1, the HUD device 1 includes, for example, a first light source 11a that emits light in the visible wavelength range, a first display unit 12a that transmits the light emitted from the first light source 11a and displays the real image RI of the display image formed in front of the occupant DR, a reflection unit 13 that reflects the first light ray L1 representing the display image displayed on the first display unit 12a toward the windshield WS (light-transmitting member), and a control unit 15 that controls the display content of the first display unit 12a. These are housed in the housing 16. The housing 16 is provided with an opening 17 (light-emitting port) from which the first light ray L1 is emitted, and a cover glass 18 for protecting the interior is disposed at the opening 17. The windshield WS is an example of a light-projecting member, and the opening 17 is an example of a light-emitting port.

[0015] In FIG. 1, actually, an infinite number of light rays are emitted from the first display unit 12a. Here, the light ray that is emitted from the center of the first display unit 12a and passes through the center of the eyebox is shown as the first light ray L1 as a representative light ray.

[0016] The HUD device 1 is disposed below the windshield WS of the vehicle C (for example, inside the instrument panel), emits the first light ray L1, and projects it onto the windshield WS. The first light ray L1 is generated by the first light source 11a and the first display unit 12a inside the HUD device 1. The first light ray L1 emitted from the first display unit 12a passes through the reflection unit 13 and is emitted from the opening 17 of the housing 16 through the cover glass 18. The occupant DR of the vehicle C can visually recognize the real image RI as shown in FIG. 1 on the vehicle interior side with the windshield WS interposed therebetween, that is, on the front side of the windshield WS as viewed from the occupant DR, by visually recognizing the first light ray L1 reflected by the windshield WS.

[0017] In the real image RI shown in FIG. 1, for example, entertainment content, an assistant or an agent that supports the occupant DR, and a character that represents them are displayed on the front side of the windshield WS as seen from the occupant DR. Such a display provides a driving environment with reduced need for viewpoint movement and eye focus adjustment. The real image RI includes not only characters and icons indicating this information but also a background portion, which forms, for example, a substantially rectangular shape in a plan view from the occupant DR.

[0018] In FIG. 1, the first light source 11a is, for example, a light-emitting diode that emits light in the visible wavelength range mounted on a wiring board and emits white light. The first display unit 12a is provided on the side of the opening 17 along the optical path rather than the first light source 11a and has a TFT (Thin Film Transistor) type first display element (not shown) that forms light representing an arbitrary image according to a control signal sent from the control unit 15.

[0019] The reflecting unit 13 includes a first mirror 131 that reflects the first light ray L1 emitted from the first display unit 12a toward the second mirror 132, a second mirror 132 that reflects the first light ray L1 toward the third mirror 133, and a third mirror 133 that reflects the first light ray L1 toward the opening 17 that is the light exit.

[0020] As shown in FIG. 1, the first mirror 131 is disposed at a position substantially at the same height as the arrangement positions of the first light source 11a and the first display unit 12a, and reflects the first light beam L1 emitted from the first display unit 12a in a substantially horizontal direction toward the second mirror 132 disposed above the first mirror 131 in a substantially vertical direction. Here, the height in the present disclosure is the vertical direction in FIG. 1, which is the vertical distance of the vehicle C. The second mirror 132 reflects the first light beam L1 from the substantially vertical direction reflected by the first mirror 131 in a substantially horizontal direction toward the third mirror 133 disposed at a position substantially at the same height as the arrangement position of the second mirror 132. The third mirror 133 is disposed above the arrangement positions of the first light source 11a and the first display unit 12a, and reflects the first light beam L1 from the substantially horizontal direction reflected by the second mirror 132 toward the upper opening 17. Then, the first light beam L1 reflected by the third mirror 133 is emitted to the windshield WS through the cover glass 18, and the occupant DR visually recognizes the display image represented by the first light beam L1 as a real image RI.

[0021] Also, at this time, the first mirror 131 is disposed on the opening 17 side rather than the first light source 11a and the first display unit 12a along the optical path of the first light beam L1, and is disposed on the first display unit 12a side rather than the first optical focus F1 of the imaging optical system including the windshield WS, the second mirror 132, and the third mirror 133.

[0022] By arranging the first light source 11a, the first display unit 12a, and the reflection unit 13 in such an arrangement relationship, the optical path of the first light beam L1 is formed in a substantially U shape, and the size of the housing 16 can be reduced. Further, since the first optical focus F1 is located closer to the opening 17 side than the first mirror 131, it becomes possible to display the real image RI at an arbitrary appropriate position in front of the occupant DR. That is, when the first optical focus F1 is located closer to the first display unit 12a side than the first mirror 131, the first optical focus F1 moves away from the second mirror 132. As the distance increases, the real image RI is displayed at a position closer to the occupant DR and with a larger size. Therefore, it becomes very difficult for the occupant DR to view the real image RI. That is, it is preferable that the first optical focus F1 is closer to the second mirror 132. In the HUD device 1 according to the present embodiment, as shown in FIG. 1, the reflection unit 13 is arranged such that the first optical focus F1 is located at least between the first mirror 131 and the second mirror 132.

[0023] In FIG. 1, the first mirror 131 and the second mirror 132 may be concave mirrors having free-form surfaces so that the real image RI represented by the first light beam L1 can be enlarged while correcting distortion and blurring of the real image RI. The third mirror 133 may be a concave mirror to enlarge the real image RI. By doing so, it becomes possible to display the real image RI with high display quality.

[0024] Further, the first mirror 131 may be a mirror having a planar shape or a convex shape. FIG. 2 is a diagram showing a configuration in the case where the first mirror 131 is a plane mirror in the HUD device 1 according to the present embodiment. As described above, when the first mirror 131 is a concave mirror having a free-form surface, the distortion and blur of the real image RI can be corrected by the first mirror 131 and the second mirror 132, so that the display quality can be made high-quality. However, when sufficient display quality can be ensured by the second mirror 132 and the third mirror 133, for example, when sufficient display quality can be ensured by making both the second mirror 132 and the third mirror 133 concave mirrors having free-form surfaces, the first mirror 131 only needs to simply reflect the first light ray L1 from the horizontal direction in the vertical direction. Therefore, as shown in FIG. 2, a plane mirror (or a convex mirror as required) can be used. In this case, since the plane mirror only reflects the first light ray L1, the position of the mirror and the incident angle do not result from the display quality. From this, as shown in FIG. 2, by arranging the first mirror 131 so that the first light ray L1 is reflected at the position of the first optical focus F1 (the first optical focus F1 is located directly above the reflecting surface of the first mirror 131), the size of the first mirror 131 can be significantly reduced, and accordingly, the housing 16 can be miniaturized.

[0025] Here, as described above, from the viewpoint of the display position of the real image RI, it is preferable that the first optical focus F1 is closer to the second mirror 132. In addition, from the viewpoint of improving the display quality by correction, it is preferable that the first mirror 131 is arranged at a position as far as possible from the first optical focus F1. FIG. 3 is a schematic diagram showing the mode of the first light ray L1 when the first mirror 131 is arranged (A) near the first optical focus F1 and (B) away from the first optical focus F1 in the HUD device 1 according to the present embodiment. In FIG. 3, the configurations other than the first mirror 131 and the second mirror 132 are omitted.

[0026] In FIG. 3(A), when the first mirror 131 is arranged near the first optical focus F1, since the correction area S1 at the first mirror 131 becomes narrow, the number of light rays per unit area increases. That is, at the same magnification, since a plurality of light rays have to be corrected with the narrow correction area S1, it becomes difficult to sufficiently ensure the display quality. On the other hand, in FIG. 3(B), since the correction area S2 at the first mirror 131 becomes wide, the number of light rays per unit area decreases. That is, at the same magnification, a plurality of light rays can be corrected with the wide correction area S2, and the display quality can be improved.

[0027] FIG. 4 is a schematic diagram showing the positional relationship between each mirror and the first optical focus F1 in the arrangement configuration of the first mirror 131 and the second mirror 132 shown in FIG. 3(B). In FIG. 4, when the midpoint that is half of the maximum distance d between the first mirror 131 and the second mirror 132 is defined as O, if the distance between the midpoint O and the first optical focus F1 is d1 and the distance between the first mirror 131 and the first optical focus F1 is d2, the first mirror 131 and the second mirror 132 are arranged so as to satisfy the relationship d1≤d2. FIG. 4(A) shows the case where the first optical focus F1 is located closer to the first mirror 131 than the midpoint O, and FIG. 4(B) shows the case where the first optical focus F1 is located closer to the second mirror 132 than the midpoint O. However, in any case, by arranging the first mirror 131 and the second mirror 132 with the relationship d1≤d2, it is possible to perform appropriate correction suitable for each individual configuration as shown in FIG. 3(B), and the display quality can be improved.

[0028] The control unit 15 controls the first display element of the first display unit 12a so as to generate, for example, a first light ray L1 representing a display image such as the above-described entertainment content, an assistant or an agent that supports the occupant DR, and a character representing them. The first light ray L1 generated by the first display element forms a real image RI in front of the occupant DR while being enlarged and corrected via the reflection unit 13 as described above.

[0029] Regarding the first mirror 131, the second mirror 132, and the third mirror 133 included in the reflection unit 13, at least one of them may be a mirror having a free-form surface. However, by making a plurality of mirrors have a free-form surface shape, the correction quality can be improved, and the display quality can be significantly enhanced.

[0030] As described above, in the HUD device 1 according to this embodiment, it includes a first display element, a first display unit 12a that transmits the light emitted from the first light source 11a for the real image RI and displays the real image RI of the display image, and at least a reflection unit 13 that reflects a first light ray L1 representing the real image RI displayed on the first display unit 12a toward the windshield WS. The reflection unit 13 includes a first mirror 131 that reflects the first light ray L1 toward the second mirror 132, a second mirror 132 that reflects the first light ray L1 toward the third mirror 133, and a third mirror 133 that reflects the first light ray L1 toward the opening 17. The first mirror 131 is arranged along the optical path of the first light ray L1, on the side of the opening 17 rather than the first display unit 12a, and on the side of the first display unit 12a rather than the first optical focus F1 of the imaging optical system including the windshield WS, the second mirror 132, and the third mirror 133. The third mirror 133 and the first display unit 12a are arranged such that at least the height direction position of the third mirror 133 is above the height direction position of the first display unit 12a. Therefore, the light emitted from the first light source 11a passes through the first display unit 12a, is reflected by the first mirror 131, is focused on the first optical focus F1, is reflected by the second mirror 132 and the third mirror 133, and travels toward the opening 17, realizing the light ray optical path. In the configuration for realizing this light ray optical path, each component can be arranged in a substantially U-shape to achieve miniaturization of the HUD device 1.

[0031] Also, by placing the position of the first optical focus F1 on the side of the opening 17 rather than the first mirror 131, it becomes possible to display the real image RI at an arbitrary position.

[0032] Furthermore, as the position of the first optical focus F1 moves away from the second mirror 132, the real image RI appears to move closer to the occupant DR and becomes more difficult to see. However, by positioning the first optical focus F1 between the first mirror 131 and the second mirror 132, the position of the first optical focus F1 can be brought as close as possible to the second mirror 132, making it easier for the occupant DR to see the real image RI.

[0033] Furthermore, when the first mirror 131 is arranged near the first optical focus F1, the size of the first mirror 131 itself can be reduced, thereby enabling miniaturization of the HUD device 1.

[0034] Also, by using the second mirror 132 as a concave mirror with a free-form surface, an image correction effect can be achieved by the free-form surface, improving the display quality.

[0035] Furthermore, by using the first mirror 131 as a plane mirror and arranging the first optical focus F1 on the first mirror 131, for example, if the third mirror 133 is a concave mirror with a free-form surface, sufficient improvement in display quality can be achieved with only the second mirror 132 and the third mirror 133, and the first mirror 131 can be a plane mirror. In this case, by arranging the first optical focus F1 on the first mirror 131, the size of the first mirror 131 can be reduced, and the entire HUD device 1 can be further miniaturized.

[0036] Furthermore, when the first mirror 131 is a concave mirror with a free-form surface and the first optical focus F1 is arranged between the first mirror 131 and the second mirror 132 along the optical path of the first light ray L1, for example, in the case of performing virtual image display described later in the second embodiment, correction for virtual image display needs to be performed by the third mirror 133, and at this time, the third mirror 133 cannot be used as a correction mirror for real image display. Therefore, by performing correction with the free-form surface of the first mirror 131, the display quality in the case of performing real image display can be ensured. At this time, in particular, when the first mirror 131 is separated from the position of the first optical focus F1, a wider correction area S1, S2 can be ensured on the first mirror 131, further improving the display quality.

[0037] (Second Embodiment of the Present Invention) The HUD device according to this embodiment will be described with reference to FIG. 5. The HUD device 1 according to this embodiment is configured to display a virtual image VI outside the vehicle across the windshield WS in the HUD device 1 according to the first embodiment. Note that descriptions overlapping with those of the first embodiment in this embodiment are omitted.

[0038] FIG. 5 is a diagram showing a configuration when a virtual image VI or a real image RI is displayed in the HUD device 1 according to this embodiment. In FIG. 5, in addition to the configuration of FIG. 1, the HUD device 1 further includes a second light source 11b and a second display unit 12b. The second light source 11b is, for example, a light-emitting diode that emits light in the visible wavelength range mounted on a wiring board and emits white light. The second display unit 12b is provided on the side of the opening 17 along the optical path from the second light source 11b, and has a TFT-type second display element (not shown) that forms light representing an arbitrary image according to a control signal sent from the control unit 15. The second display unit 12b transmits the light emitted by the second light source 11b and displays a virtual image VI of a display image formed outside the vehicle across the windshield WS. In FIG. 5, the first light ray L1 and the second light ray L2 are shown as solid lines, the light ray representing the display image of the real image RI associated with the first light ray L1 is shown as a dotted line, and the light ray representing the display image of the virtual image VI associated with the second light ray L2 is shown as a dashed-dotted line.

[0039] In FIG. 5, the second mirror 132 is a half mirror and transmits the second light ray L2 representing the virtual image VI displayed on the second display unit 12b. The second light ray L2 transmitted through the second mirror 132 is reflected by the third mirror 133 and emitted toward the windshield WS. The second display unit 12b is arranged on the side of the opening 17 rather than at the position of the second optical focus F2 of the imaging optical system including the windshield WS, the second mirror 132, and the third mirror 133 along the optical path of the second light ray L2. With such a configuration, when the first light source 11a is lit, the passenger DR can visually recognize the real image RI inside the vehicle across the windshield WS, and when the second light source 11b is lit, the passenger DR can visually recognize the virtual image VI outside the vehicle across the windshield WS.

[0040] In addition, for the virtual image VI shown in FIG. 5, information that highly requires the attention of the occupant DR is displayed, such as vehicle information such as the speed of the vehicle C and the engine speed, route guidance displays such as turn-by-turn and maps, blind spot indicators, and warning displays such as a warning for exceeding the speed limit.

[0041] Also, the second mirror 132 may be other than a half mirror, as long as it reflects the first light beam L1 on one surface and transmits the second light beam L2 incident from the other surface. For example, a wavelength-selective film may be attached, or a transmissive member with a coating may be used.

[0042] In the HUD device 1 shown in FIG. 5, since the imaging optical system that generates the virtual image VI is formed only by the windshield WS and the third mirror 133, the magnification by the concave mirror of the third mirror 133 is high. Further, the third mirror 133 has a free-form surface to ensure the display quality of the virtual image VI, and is used as a correction mirror for displaying the virtual image VI. In this case, the third mirror 133 cannot be used as a correction mirror for displaying the real image RI. Therefore, the second mirror 132 is made into a concave mirror having a free-form surface and used as a correction mirror for displaying the real image RI. However, if sufficient display quality cannot be ensured only by this second mirror 132, the first mirror 131 may be further made into a concave mirror having a free-form surface and used as a correction mirror for displaying the real image RI. On the other hand, as described in the first embodiment, when only the real image RI is displayed, since the third mirror 133 can be used as a correction mirror for displaying the real image RI, sufficient display quality can be ensured by the second mirror 132 and the third mirror 133, and the first mirror 131 can be a plane mirror that simply reflects the first light beam L1.

[0043] That is, in a configuration where the virtual image VI and the real image RI as shown in FIG. 5 are switched and displayed, the third mirror 133 is a concave mirror having a free-form surface, and the virtual image VI is enlarged and corrected. Further, the second mirror 132 is a concave mirror having a free-form surface similar to the third mirror 133 in order to enlarge and correct the real image RI, but has a structure in which the first light beam L1 is reflected and the second light beam L2 is transmitted. And when it is necessary to further improve the display quality of the real image RI, the first mirror 131 is a concave mirror having a free-form surface, and the real image RI is enlarged and corrected. When the display quality of the real image RI is sufficiently ensured by the second mirror 132, the first mirror 131 is a plane mirror, and the first optical focus F1 is arranged directly above the first mirror 131, so that the size of the first mirror 131 can be made extremely small.

[0044] Thus, in the HUD device 1 according to the present embodiment, in the HUD device 1 according to the first embodiment, a second display element is provided, and a second display unit 12b that transmits the light emitted from the second light source 11b for the virtual image VI and displays the virtual image VI of the display image is further provided. The second mirror 132 transmits the second light beam L2 representing the virtual image VI displayed on the second display unit 12b, and the third mirror 133 reflects the second light beam L2 toward the windshield WS. The second display unit 12b is disposed closer to the opening 17 side than the position of the second optical focus F2 of the imaging optical system including the windshield WS, the second mirror 132, and the third mirror 133 along the optical path of the second light beam L2. In order for the passenger DR to visually recognize the virtual image VI of the display image, it is possible to realize a HUD device 1 that is miniaturized while improving the display quality, and a HUD device 1 that switches and displays the virtual image VI and the real image RI.

[0045] In addition, in each of the above embodiments, the windshield WS is used as the light-transmitting member, but a plane glass or a combiner may be used.

Description of Reference Numerals

[0046] C Vehicle DR Passenger F1 First optical focus F2 Second optical focus L1 First light ray L2 Second light ray RI Real image VI Virtual image WS Windshield 1 HUD device 11a First light source 11b Second light source 12a First display unit 12b Second display unit 13 Reflective part 15 Control unit 16 Housing 17 Opening 18 Cover glass 131 First mirror 132 Second mirror 133 Third mirror

Claims

1. A head-up display device having an emission port, and emitting display light from the emission port toward a light-transmitting member to visually recognize at least a real image of a display image represented by the display light, comprising a first display element, and a first display unit that transmits light emitted from a first light source for a real image and displays the real image of the display image; and at least a reflection unit that reflects a first light ray representing the real image displayed on the first display unit toward the light-transmitting member; The reflection unit comprises: a first mirror that reflects the first light ray toward a second mirror; the second mirror that reflects the first light ray toward a third mirror; and the third mirror that reflects the first light ray toward the emission port; The first mirror is disposed along the optical path of the first light ray, on the emission port side of the first display unit, and on the first display unit side of a first optical focus of an imaging optical system including the light-transmitting member, the second mirror, and the third mirror; The third mirror and the first display unit are disposed such that at least a height-direction position of the third mirror is above a height-direction position of the first display unit. The head-up display device is characterized by the above.

2. The head-up display device according to claim 1, wherein the second mirror is a concave mirror having a free-form surface.

3. The first mirror is a plane mirror, and the first optical focus is disposed on the first mirror. The head-up display device according to claim 2 is characterized by the above.

4. The first mirror is a concave mirror having a free-form surface, and the first optical focus is disposed between the first mirror and the second mirror along the optical path of the first light ray. The head-up display device according to claim 2 is characterized by the above.

5. The head-up display device further comprises a second display element, and a second display unit that transmits light emitted from a second light source for a virtual image and displays the virtual image of the display image, the second mirror transmits a second light ray representing the virtual image displayed on the second display unit, the third mirror reflects the second light ray toward the light-transmitting member, the second display unit is disposed on the emission port side of a position of a second optical focus of an imaging optical system including the light-transmitting member, the second mirror, and the third mirror along the optical path of the second light ray, and visually recognizes the virtual image of the display image. The head-up display device according to claim 4 is characterized by the above.

Images