Projection display system for vehicle

Abstract

The invention relates to a projection display device for a motor vehicle, comprising: a projection device which is designed to output image-bearing light in order to project a display image into the eye region of a vehicle occupant; an optical device having at least one optical element, which is designed to focus the image-bearing light into the eye region such that the display image is perceptible in the eye region of the vehicle occupant; and a movable housing element which can be adjusted into a normal position in which the projection operation is ensured and a shielding position in which the housing element is arranged between the display device and the at least one optical element.

Description

Technical Field

[0001] The present invention relates to a projection display system for realizing a head-up display in a vehicle. The present invention also relates to a measure for protecting the projection display system from direct sunlight. Background Art

[0002] A projection display system generally has a self-luminous display device, and the display image thereof is reflected through a concave mirror and through a cover glass onto the front glass area or the combiner surface into the eyes of the vehicle occupant. Other optical elements may be arranged between the display surface of the display device and the concave mirror if possible.

[0003] The concave mirror is used to project and focus the display image onto the retina of the vehicle occupant's eyes, so that the occupant perceives the image plane of the display image as floating several meters in front of the vehicle. Conversely, when direct light is incident, especially when solar radiation passes through the cover glass and enters the interior of the projection display system, focusing occurs through the concave mirror, so that the display device will be strongly heated due to the bundled sunlight. Accordingly, measures are to be provided to protect the display device from overheating.

[0004] Due to the vehicle movement during vehicle operation, the action time of the bundled sunlight on the display device is limited, so that no additional protection measures are required therefor. In addition, protection usually also has a negative impact on the function, especially on the perceptibility of the display image, which is unacceptable during vehicle operation.

[0005] However, if the vehicle is in a parked position, the bundled sunlight incident on the concave mirror through the cover glass may, in some cases, heat the display device over a relatively long period of time and may damage it if possible. Therefore, it is generally stipulated that the concave mirror is pivoted in the parked position and thereby ensures that the bundled sunlight does not fall on the display surface of the display device.

[0006] However, in order to pivot the concave mirror, a relatively large movement space is required, because the concave mirror extends over most of the dimensions of the housing and largely determines the depth of the projection display device. Generally, in the parked position, the concave mirror is tilted forward so that the incident sunlight is directed by the concave mirror to an inner wall of the housing, or the incident sunlight does not reach the mirror surface of the concave mirror at all.

[0007] When the concave mirror is pivoted, attention should be paid in the structural design of the projection display system that the upper edge of the concave mirror does not collide with the usually curved cover glass. Therefore, a spacing is to be provided between the concave mirror and the cover glass, and this spacing increases the structural height of the projection display system.

[0008] Document DE102011105689A1 also discloses a display device, which includes a liquid crystal display for reproducing an image, a sensor system for determining the irradiation intensity of incident optical radiation and for determining the current sun position relative to the liquid crystal display, an adjustable shielding device for protecting the liquid crystal display from the influence of incident optical radiation, and a control unit, which is configured to check whether the irradiation intensity determined by the sensor system is higher than a predetermined threshold and whether the current sun position falls within a predetermined angular range, and to control the shielding device according to the result of this check such that it interrupts the optical path of the part of the optical radiation falling on the liquid crystal display. The shielding device may include a diaphragm that is pivotable in front of the liquid crystal display and / or in the mentioned optical path and / or a pivotable mirror arranged in the mentioned optical path of the incident optical radiation and for imaging the image reproduced on the liquid crystal display.

[0009] Document DE10220180B4 discloses a head-up display for a vehicle, the head-up display having a display device mounted in the instrument panel, by means of which an image is projected upward through an opening in the instrument panel for reflection on a screen arranged above the instrument panel, wherein the image is inserted into the driver's field of view, and the head-up display having a covering unit, the covering unit having a covering body that is movable to open and close the opening, and the covering unit having a partition that is movable between an upright position and a lying position, when the opening is open, the partition is erected and arranged in an upright position on the part of the opening edge facing the driver, thereby preventing the driver from directly seeing the opening and seeing through the opening, and when the opening is closed, the partition lies flat along the upper side of the instrument panel in the lying position.

[0010] The latter solution requires a high structural cost to achieve the shielding of the display device. Summary of the Invention

[0011] The object of the present invention is to provide a possibility, especially when the vehicle is in a parked state or a stationary state, such that the sunlight incident on the projection display device does not cause damage to the display device due to excessive heating.

[0012] This object is solved by the projection display system according to claim 1.

[0013] Other design solutions are given in the dependent claims.

[0014] According to a first aspect, a projection display device for a motor vehicle is provided, the projection display device including:

[0015] - a projection device configured to output light carrying an image for projecting a display image into the eye region of a vehicle occupant;

[0016] - An optical device having at least one optical element, the optical device being configured to focus light carrying an image into the eye region such that the displayed image is perceivable in the eye region of a vehicle occupant;

[0017] - A movable housing part, the housing part being adjustable to a normal position ensuring projection operation and a shielding position, wherein, in the shielding position, the housing element is arranged between the display device and the at least one optical element.

[0018] Projection display systems for implementing a head-up display in a vehicle are usually installed in the instrument panel. There is a transparent cover glass on the upper side, which protects the projection optical device and the display device. The projection display system is used to focus the display image of a self-luminous display device through a concave mirror, direct it through the cover glass, so that the display light is reflected on the combiner surface or the windshield and focused in the eyes of a vehicle occupant, especially the driver. The focusing is performed such that the display image is perceived by the driver in a display plane appearing several meters in front of the vehicle. However, especially in small and medium-sized vehicles, the structural space for accommodating the projection display device is very limited.

[0019] As mentioned at the beginning, the measures taken so far to achieve a shielding position to avoid overheating of the display device are disadvantageous in terms of the structural height and / or structural cost of the projection display device. According to the above provisions for the projection display device, the housing element of the projection display device is configured to be movable, so that the housing element can be positioned in the optical path between the display device and the concave mirror in the shielding position as a shielding element when protection conditions exist or in the non-active state of the vehicle.

[0020] The at least one optical element may include a concave mirror or a converging lens.

[0021] The housing element configured as a shielding element is preferably pivotally supported, so that the housing element is movable, for example, by a mechanical crank-lever structure and can be brought from the operating position to the protection position in a simple manner by means of an adjustment actuator or manually. The core idea in the above projection display device is to prohibit the possibility that sunlight directly incident through the cover glass is directed to the display surface by the concave mirror.

[0022] The housing element may include a bottom plate (bottom part) opposite to the cover glass or the side wall of the housing.

[0023] It may be provided that the bottom plate is pivotally arranged, especially pivotally arranged on a pivot axis below the concave mirror as the at least one optical element.

[0024] The surface of the housing element facing away from the display device can be configured to be at least partially reflective.

[0025] Furthermore, the housing element can be automatically movable by means of an adjustment generator (Stellgeber), wherein the control unit is configured to adjust to a shielding position when the vehicle is in an inactive state, when the measured temperature of the display device is too high, and / or when the projection device is switched off. Description of the Drawings

[0026] The embodiments are explained in more detail below with the aid of the accompanying drawings. Shown are:

[0027] Figure 1 A schematic cross-sectional view of a projection display device for a motor vehicle;

[0028] Figure 2 A schematic perspective view of the projection display device; and

[0029] Figure 3 Shown Figure 2 A schematic cross-sectional view of the projection display device in the shielding position. Detailed Description of the Embodiments

[0030] Figure 1 A cross-sectional view of a projection display device 1 (e.g., a head-up display) is schematically shown. The projection display device 1 includes an optical projection device 2 and a cover member with a cover glass 3.

[0031] The projection display device 1 is basically inserted into an opening 9 in the upper side 8 of the instrument panel 7 between the steering wheel and the front glass 5, such that the projection display device is basically in contact with or adjacent to the upper side 8.

[0032] The projection device 2 outputs a projection beam L in a suitable manner, which projection beam points in the projection direction P to the display area 4 of the front glass 5 of the motor vehicle (alternatively, for example, also to the display area of a combiner surface). The projection device 2 includes in a known manner a system consisting of one or more mirrors 21, in particular concave mirrors, and possibly lenses (not shown) and a display device 22.

[0033] The display device 22 can preferably be configured as a self-luminous LCD, MicroLED, OLED, etc., in order to output a display image.

[0034] The display image output by the display device 22 is directed as a projection beam L in the projection direction P through one or more mirrors 21 and projected onto the display area 4. The projection beam L projected onto the display area 4 is reflected on the display area 4 and directed towards the eye area B of the vehicle occupant, thereby generating an image in the eyes of the vehicle occupant that corresponds to the display image of the display device 22 and can thus present information.

[0035] A cover glass 3 can be arranged adjacent to the projection device 2, which protects the projection device 2 from being contaminated by, for example, dust particles and ensures anti-glare protection. The cover glass 3 can be substantially configured to be curved. However, a planar shape or an approximately planar shape of the cover glass 3 is also conceivable.

[0036] Figure 2 The projection display device 1 in the housing 23 is schematically shown. In the longitudinal direction of the vehicle, the display surface of the display device 22 is located at the rear end of the housing of the projection display device 1.

[0037] Mirrors 21, in particular concave mirrors, are arranged at opposite ends of the housing 23, so that the display image is reflected in the vertical direction such that the display image points towards the display area of the front glass 5 or the combiner surface (Combiner-Fläche) of the vehicle.

[0038] Furthermore, the housing 23 has two opposite side walls 24 and a bottom member 25, which enclose the optical device of the projection device 2.

[0039] The angular arrangement of the concave mirror 21 is selected such that, depending on the tilt angle of the cover glass, the display image points through the combiner surface into the eye area B of the vehicle occupant. The focal length of the concave mirror 21 is selected such that the display image is focused in the eyes of the vehicle occupant.

[0040] When sunlight directly enters through the cover glass 3, it must be ensured that the sunlight does not point through the concave mirror 21 towards the display surface of the display device 22, because due to the light bundling effect, special heat development may occur in the display surface area.

[0041] For this purpose, as Figure 3 shown in the cross-sectional view, it can be provided that the bottom member 25 of the housing 23 is pivotally supported such that it can pivot with its free end into the optical path between the display surface and the concave mirror 21 in the shielding position. In particular, the bottom member 25 of the housing 23 can be pivotally arranged at the lower end of the concave mirror 21 and can be pivoted upwards by means of a crank lever 26 or other adjustment mechanism, so that the protruding end moves in front of the display surface of the display device 22. In this way, sunlight can be effectively shielded from the display device 22.

[0042] The side of the pivotable bottom part 25 facing the concave mirror 21 can be correspondingly configured so as to at least partially reflect sunlight, so that due to the absorption of sunlight, excessive heat development does not occur in the area of the bottom part 25. In addition, the spacing between the bottom part 25 and the display surface causes that even if the bottom part 25 heats up, there will be no excessive heat input to the display device 22.

[0043] The adjustment of the bottom part 25 to the shielding position can be automatically controlled by the control unit 27. The control unit 27 can be configured such that it occupies the shielding position when the vehicle is not in operation (for example, in a stationary state or when not in use), when the temperature of the display device is too high (measured by a temperature sensor arranged there), and / or when the projection display device 1 is switched off.

[0044] List of reference numerals

[0045] 1 Projection display device

[0046] 2 Projection device

[0047] 21 Mirror

[0048] 22 Display device

[0049] 23 Housing

[0050] 24 Side wall

[0051] 25 Bottom part

[0052] 26 Crank lever

[0053] 27 Control unit

[0054] 28 Adjustment generator

[0055] 3 Cover glass

[0056] 4 Display area

[0057] 5 Front glass

[0058] 7 Instrument panel

[0059] 8 Upper side

[0060] 9 Opening

[0061] L Projection beam

[0062] P Projection direction

Claims

1. A projection display device (1) for a motor vehicle, the projection display device comprising: - a projection device (2) configured to output light carrying an image in order to project the display image into the eye region of a vehicle occupant; - an optical device having at least one optical element (21), the optical device being designed to focus image-bearing light into the eye region so that the displayed image is perceptible in the eye region of the vehicle occupant; A movable housing element (25) which can be adjusted into a normal position ensuring a projection operation and into a shielding position, wherein in the shielding position the housing element (25) is arranged between the display device (22) and the at least one optical element (21).

2. The projection display device (1) according to claim 1, wherein: The housing element (25) comprises a bottom part (25) or a side wall (24) of the housing (23) opposite the cover glass (3).

3. The projection display device (1) according to claim 2, wherein: The bottom part is in particular designed as a bottom plate and is arranged so as to be pivotable on a pivot axis below a concave mirror as the at least one optical element (21).

4. The projection display device (1) according to claim 2, wherein: The bottom part is in particular designed as a base plate and is arranged to be pivotable on a pivot axis below the display device (22).

5. The projection display device (1) according to claim 3 or 4, wherein: The bottom part can be pivoted into the interior of the housing (23).

6. The projection display device (1) according to any one of claims 2 to 5, wherein: A surface of the housing element (25) facing away from the display device (22) is designed to be at least partially reflective.

7. The projection display device (1) according to any one of claims 1 to 6, wherein: The at least one optical element (21) comprises a concave mirror or a converging lens.

8. The projection display device (1) according to any one of claims 1 to 7, wherein: The housing element (25) can be moved automatically by means of a control generator, wherein the control unit is designed to be adjusted to a blocking position by means of the control generator when the vehicle is in an inactive state, when the measured temperature of the display device is too high and / or when the projection device is switched off.

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