Head-up display

Abstract

To reduce trouble caused by external light entering a head-up display.SOLUTION: An HUD 10 comprises an enclosure provided with an opening part 16a, an image irradiation part provided inside the enclosure and emitting image light, an optical system so configured that the image light is emitted from the opening part 16a and projected on a projection object member, and a shield mechanism 40 provided inside the enclosure to block the optical path of the optical system. The shield mechanism 40 has a movable part 40a which moves between a shield position P1 where the optical path is blocked and a standby position P2 where the optical path is not blocked.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a head-up display. [Background technology]

[0002] Conventionally, a head-up display (hereinafter referred to as HUD) has been devised that projects an image onto the windshield to enable the driver to read information when viewing the area ahead of the vehicle. The HUD reflects display light showing an image generated by a display device using a reflective member such as a concave mirror, and then emits the light from an opening in a case to the outside of the device. The emitted display light illuminates a transmissive reflective member such as a windshield, allowing the viewer to view a virtual image (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-150001 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with a typical HUD, external light (sunlight) entering the vehicle from above the windshield during the daytime enters the HUD, and the light is reflected and concentrated by the internal concave mirror, which can then be concentrated on the LCD screen, etc., potentially causing malfunctions.

[0005] The present invention has been made in view of the above circumstances, and one exemplary purpose of the present invention is to provide a new technique for reducing problems caused by external light entering a head-up display. [Means for solving the problem]

[0006] In order to solve the above problems, a head-up display according to one aspect of the present invention includes a housing having an opening, an image irradiation unit provided inside the housing and irradiating image light, an optical system configured so that the image light is emitted from the opening and projected onto a projection target, and a shielding mechanism provided inside the housing and shielding an optical path in the optical system. The shielding mechanism has a movable part that moves between a shielding position where it shields the optical path and a retracted position where it does not shield the optical path.

[0007] According to this aspect, the optical path of the optical system is blocked, so that external light incident from the opening is less likely to travel backward along the optical path and reach the image projection unit.

[0008] The optical system may include a first reflecting section that reflects image light emitted from the image emitting section, a second reflecting section that reflects the image light reflected by the first reflecting section, and a wall section that is provided between the first reflecting section and the second reflecting section and that prevents stray light. The movable section may include at least a portion of the wall section. This reduces the space required for providing the movable section.

[0009] The wall may be provided at a position separating a first optical path along which image light irradiated from the image irradiating unit travels toward the first reflecting unit and a second optical path along which image light reflected by the first reflecting unit travels toward the second reflecting unit, thereby suppressing stray light inside the housing.

[0010] The blocking mechanism may move the movable part between a blocking position where the first optical path is blocked and a retracted position, thereby making it possible to reduce the size of the movable part.

[0011] The first reflecting unit may have a smaller reflecting area than the second reflecting unit, and the optical system may further include a driving unit that changes the orientation of the reflecting surface of the second reflecting unit. The driving unit may be configured to move the movable unit between a shielding position and a retracted position. This allows a single driving unit to change the orientation of the reflecting surface of the second reflecting unit and move the movable unit.

[0012] Any combination of the above components, and conversion of the expression of the present invention between a manufacturing method, a lighting device or illumination, a light-emitting module, a light source, etc. are also valid aspects of the present invention. [Effects of the Invention]

[0013] According to the present invention, problems caused by external light entering a head-up display can be reduced. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of a head-up display (HUD) according to an embodiment of the present invention, viewed from the side. [Figure 2] 2 is a cross-sectional view showing a detailed internal structure of the HUD according to the present embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be given the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, the embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0016] FIG. 1 is a schematic cross-sectional view of a head-up display (HUD) according to the present embodiment, as viewed from the side. The HUD 10 shown in FIG. 1 is an image projection device that projects an image onto a windshield 12, which is a projection target. Another example of a projection target is a combiner. The HUD 10 is configured to display predetermined information as an image to a vehicle user so that the image is superimposed on the real space outside the vehicle (particularly, the surrounding environment in front of the vehicle). The image information displayed by the HUD 10 is, for example, vehicle driving information related to the driving of the vehicle and / or surrounding environment information related to the surrounding environment of the vehicle (particularly, information related to objects present outside the vehicle).

[0017] At least a portion of the HUD 10 is located inside the vehicle. Specifically, the HUD 10 is installed in a predetermined location inside the vehicle. For example, the HUD 10 is disposed in the dashboard of the vehicle.

[0018] As shown in FIG. 1, the HUD 10 includes an image display main body 14. The image display main body 14 has a case 16 and a light-transmitting sheet 18. The light-transmitting sheet 18 is made of a flexible material that transmits visible light (e.g., polycarbonate resin or acrylic resin). The image display main body 14 has an image output unit 20, a concave mirror 22, and a concave mirror 24 inside the case 16.

[0019] The image output unit 20 is installed within the case 16 so as to emit light upward. Specifically, the image output unit 20 has an image display unit such as a liquid crystal display or an organic EL display at its upper part. The concave mirror 22 is arranged on the optical path of the light emitted from the image output unit 20. Specifically, the concave mirror 22 is arranged above the image output unit 20 and is configured to reflect the light emitted from the image output unit 20 towards the concave mirror 24.

[0020] The concave mirror 24 is disposed on the optical path of light emitted from the image output unit 20 and reflected by the concave mirror 22. Specifically, the concave mirror 24 is disposed in front of the image output unit 20 and the concave mirror 22 within the case 16. The concave mirror 24 is configured to reflect the light emitted from the image output unit 20 toward the windshield 12. The concave mirror 24 has a reflective surface that is concavely curved to form a predetermined image, and reflects the light image emitted from the image output unit 20 and formed thereon at a predetermined magnification. The concave mirror 24 includes, for example, a drive mechanism 26 that can change the position and orientation of the concave mirror 24 based on a control signal transmitted from the display control unit. The drive mechanism 26 may be provided on the concave mirror 22 instead of the concave mirror 24. The display control unit is housed within the image output unit 20. The display control unit may be provided external to the image output unit.

[0021] Light emitted from the image output unit 20 is reflected by the concave mirror 22 and the concave mirror 24, and passes through the light-transmitting sheet 18 that covers the opening 16a of the case 16 before being emitted to the outside. The light emitted from the light-transmitting sheet 18 is irradiated onto the windshield 12. A portion of the light irradiated onto the windshield 12 is reflected toward the user's viewpoint E. As a result, the user perceives the light emitted from the image display main body 14 as a virtual image formed at a predetermined distance in front of the windshield 12. As a result of the image displayed by the windshield 12 being superimposed on the real space in front of the vehicle through the windshield 12, the user can visually perceive a virtual image object I formed by the predetermined image as floating above the road outside the vehicle.

[0022] Fig. 2 is a cross-sectional view showing a detailed internal structure of the HUD according to this embodiment. As shown in Fig. 2, the light-transmitting sheet 18 is provided midway along the optical path of the image light L emitted from the image output unit 20 toward the windshield 12. Therefore, sunlight S that has passed through the windshield 12 may enter the interior of the HUD 10 through the light-transmitting sheet 18. If the sunlight S travels backward along the optical path of the image light L and is collected on the image output unit 20, it may cause malfunctions in the components that make up the image output unit 20.

[0023] The image output section 20 according to this embodiment includes a liquid crystal panel 28 and a light source unit 30. The light source unit 30 is a backlight source for the liquid crystal panel 28. The light source unit 30 includes a substrate 32 on which light-emitting elements are mounted, a primary lens 34 that condenses light emitted from the light-emitting elements, a reflector 36 that reflects the condensed light, and a lens 38 that irradiates the light reflected by the reflector 36 onto the rear surface of the liquid crystal panel 28. The light source unit 30 may be provided below the liquid crystal panel 28 with its light-emitting surface facing upward. In this case, the reflector 36 is not necessary, thereby enabling the image output section to be made more compact.

[0024] As described above, if sunlight S that has entered the interior of HUD 10 is concentrated on liquid crystal panel 28, there is a possibility that a failure due to overheating may occur. Therefore, in this embodiment, HUD 10 includes case 16 as a housing having opening 16a, liquid crystal panel 28 provided inside case 16 as an image irradiating unit that irradiates image light L, an optical system (concave mirrors 22, 24) configured to emit image light L from opening 16a and project it onto windshield 12, and a shielding mechanism 40 provided inside case 16 that shields the optical path in the optical system.

[0025] The shielding mechanism 40 has a movable part 40a that moves between a shielding position P1 where the optical path is shielded and a retracted position P2 where the optical path is not shielded. The image projection part may use an organic EL display instead of a liquid crystal panel. The movable part 40a is a plate-shaped member, and a drive part 40b such as a motor or solenoid is provided at the fulcrum of rotation.

[0026] This blocks the optical path of the optical system, making it difficult for external light (sunlight S) incident through the opening 16a to travel backward along the optical path and reach the liquid crystal panel .

[0027] The optical system includes a concave mirror 22 that reflects image light L emitted from the liquid crystal panel 28, a concave mirror 24 that reflects the image light L reflected by the concave mirror 22, and a wall portion 42 that is provided between the concave mirror 22 and the concave mirror 24 and prevents stray light. The movable portion 40a includes at least a portion of the wall portion 42. This allows the space required to provide the movable portion 40a to be reduced.

[0028] The wall portion 42 is provided at a position separating a first optical path L1 along which the image light L emitted from the liquid crystal panel 28 travels toward the concave mirror 22, and a second optical path L2 along which the image light L reflected by the concave mirror 22 travels toward the concave mirror 24. This makes it possible to suppress stray light inside the case 16.

[0029] The shielding mechanism 40 moves the movable part 40a between a shielding position P1 where the first optical path L1 is shielded and a retracted position P2, thereby making it possible to reduce the size of the movable part 40a.

[0030] Concave mirror 22 has a smaller reflective area than concave mirror 24. The optical system further includes a drive mechanism 26 that changes the orientation of the reflective surface of concave mirror 24. Drive mechanism 26 includes a drive unit 40b that is configured to move movable unit 40a between shielding position P1 and retracted position P2. Drive unit 40b is connected to drive mechanism 26 via a control unit and a linking mechanism (not shown). This allows the change in the orientation of the reflective surface of concave mirror 24 and the movement of movable unit 40a to be achieved by a single drive unit. For example, the tilt operation of concave mirror 24 and the rotation operation of movable unit 40a may be linked and driven by a single drive unit.

[0031] Although the present invention has been described above with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and suitable combinations and substitutions of the configurations of the embodiments are also included in the present invention. Furthermore, it is possible to suitably rearrange the combinations and processing orders in the embodiments based on the knowledge of those skilled in the art, and to make modifications to the embodiments such as various design changes, and such modified embodiments are also included in the scope of the present invention. [Explanation of symbols]

[0032] 10 HUD, 12 windshield, 14 image display main body, 16 case, 16a opening, 18 light-transmitting sheet, 20 image output section, 22 concave mirror, 24 concave mirror, 26 drive mechanism, 28 liquid crystal panel, 40 shielding mechanism, 40a movable section, 40b drive section, 42 wall section, L1 first optical path, L2 second optical path, P1 shielding position, P2 retracted position.

Claims

1. a housing having an opening; an image irradiating unit provided inside the housing and configured to irradiate image light; an optical system configured so that the image light is emitted from the opening and projected onto a projection target; a shielding mechanism provided inside the housing and configured to shield an optical path in the optical system, The head-up display according to claim 1, wherein the blocking mechanism has a movable part that moves between a blocking position where the optical path is blocked and a retracted position where the optical path is not blocked.

2. The optical system comprises: a first reflecting section that reflects the image light irradiated from the image irradiating section; a second reflecting portion that reflects the image light reflected by the first reflecting portion; a wall portion provided between the first reflecting portion and the second reflecting portion to prevent stray light; The head-up display according to claim 1 , wherein the movable portion includes at least a part of the wall portion.

3. 3. The head-up display according to claim 2, wherein the wall portion is provided at a position separating a first optical path along which image light irradiated from the image irradiation portion travels toward the first reflection portion, and a second optical path along which image light reflected by the first reflection portion travels toward the second reflection portion.

4. The head-up display according to claim 3 , wherein the blocking mechanism moves the movable part between the blocking position where the first optical path is blocked and the retracted position.

5. the first reflecting portion has a smaller reflecting area than the second reflecting portion; the optical system further includes a drive unit that changes the orientation of the reflecting surface of the second reflecting unit, 5. The head-up display according to claim 2, wherein the drive unit is configured to move the movable unit between the blocking position and the retracted position.

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