Vehicle display device

Abstract

The device comprises a display device (10), a reflector (40) that reflects a display light from the display device arranged in a housing (61) and causes the reflected light to be projected onto a projection target part (Rwf), and a control unit (50) that controls the display light depending on an eye point (EP) or an eye box (EB). The display device includes a backlighting unit (20) that scatters and distributes light from a light source (21) onto a radiation surface (20a), and a translucent, plate-shaped display unit (30) that causes the radiation light incident on the radiation target surface (30a) to pass through and be emitted by an emission surface (30b) as a display light.The display unit is inclined relative to the radiating surface such that the distance between the second edges, which define the lower edges of a virtual image in the vertical direction on the radiating surface, and the radiating target surface is greater than the distance between the first edges, which define the upper edges of the virtual image, wherein the control unit provides the luminance of the radiant light emitted from the radiating surface to the radiating target surface to be higher at the second edge than at the first edge in order to reduce any unevenness in the luminance of the display light emitted by the emission surface of the display unit.

Description

Field of invention

[0001] The present invention relates to a vehicle display device background

[0002] Traditionally, a vehicle is equipped with a vehicle display device that presents information as a virtual image to an occupant inside the vehicle. The vehicle display device is usually depicted as a head-up display and comprises a display device that emits display information as a display light for projection onto a projection target, and a reflector that reflects the display light emitted by the display device and projects the display light onto the projection target. The vehicle display device allows an occupant to visually perceive display information corresponding to the display light projected onto the projection target as a virtual image. This type of vehicle display device is described, for example, in the patent literature cited below.The vehicle display device described in patent literature 1 tilts an emission surface of a translucent display unit to prevent external light reflected to the emission surface by a reflecting element from being reflected back to the reflecting element, and thus avoid glare from the external light. Reference list patent literature

[0003] Patent literature 1: JP 2019 - 101 056 A Summary Problem statement

[0004] A translucent display unit allows light emitted from a rear light source behind it to pass through and emits the light from its emission surface as a display light towards the reflector. A conventional vehicle display device causes the display unit to tilt relative to the optical axis of the light directed from the rear light to the reflector, resulting in a decrease in luminance at positions far from the rear light and consequently, an unevenness in luminance.

[0005] Therefore, the present invention aims to provide a vehicle display device with reduced luminance unevenness. Problem solving

[0006] The present invention comprises: a housing; a display device arranged in the housing and configured to emit display information as a display light, which is visually perceived by an occupant in a vehicle interior as a virtual image; at least one reflector configured to reflect the display light emitted by the display device in the housing and to cause the display light to be projected through an opening in the housing onto a projection target in the vehicle interior; and a control unit configured to control the display light depending on an eye point of the occupant or an eye box, which is a region of eye points that allows the visual perception of the virtual image; wherein the display device includes a backlighting unit,which is configured to scatter and distribute the light from a light source from a radiating surface, and comprises a translucent, plate-shaped display unit configured to cause radiant light incident from the radiating surface onto a radiating target surface to be transmitted and emitted by an emissive surface as the display light, wherein the display unit is inclined relative to the radiating surface such that, between the radiating surface and the reflector arranged in the direction of an optical axis of the backlighting unit with respect to the radiating surface, the distance between first edges defining lower edges of the virtual image in a vertical direction on the radiating surface and the radiating target surface is greater than the distance between second edges defining upper edges of the virtual image in the vertical direction on the radiating surface and the radiating target surface.wherein the control unit controls the backlighting unit to provide the luminance of the radiant light incident from the radiating surface onto the radiating target surface to be higher at the first edge than at the second edge, thereby reducing the unevenness of the luminance of the display light to be emitted from the emission surface of the display unit. Advantageous effects of the invention

[0007] The vehicle display device according to the present invention provides the luminance of the emission surface of the display unit to be higher at the first edge than at the second edge in order to reduce any unevenness in the luminance of the display light emitted by the emission surface over the entire emission surface and thereby improve the visibility of the virtual image display. Brief description of the drawings Fig. Figure 1 is a schematic view showing a vehicle display device of one embodiment. Fig. Figure 2 is a schematic view showing a display device of the embodiment. Fig. Figure 3 is a schematic view showing an exemplary arrangement of a light source. Fig. Figure 4 is a schematic view showing the relationship between the emission angle and the light transmittance in a display unit. Fig. Figure 5 is a schematic view showing an unevenness in the luminance in the display unit. Fig. Figure 6 is a schematic view showing an example of map data of a luminance correction value relative to the luminance of an external light. Fig. Figure 7 is a schematic view showing a vehicle display device of a modification. Fig. Figure 8 is a schematic view showing a display device of a modification. Description of embodiments

[0008] In the following, an embodiment of a vehicle display device according to the present invention is described in detail with reference to the drawings. However, the invention is not limited to the embodiments described here. [Versions]

[0009] In the following, an embodiment of the vehicle display device according to the present invention is described with reference to Fig. 1 to 6 described.

[0010] Fig. Figure 1 shows a vehicle display device according to an embodiment specified by reference numeral 1. The vehicle display device 1 is usually referred to as a head-up display and displays information in the form of a virtual image for an occupant inside a vehicle (such as an automobile).

[0011] The vehicle display device 1 comprises a display device 10 which emits display information in the form of a display light so that an occupant in the vehicle interior can perceive a virtual image, and in a housing 61 described below ( Fig. 1) is arranged. The display device 10 comprises a backlighting unit 20 and a translucent, plate-shaped display unit 30 and causes light radiated from the backlighting unit 20 to the display unit 30 to pass through and then be emitted by the display unit 30 as the display light for the display information ( Fig. 1).

[0012] Furthermore, the vehicle display device 1 comprises at least one reflector arranged in the housing 61, which reflects the display light emitted by the display device 10 and causes the display light to be projected onto a projection target part Rwf in the vehicle interior through an opening 61a of the housing 61. In this embodiment, a single reflector 40 is provided ( Fig. 1) The reflector 40 is, for example, a magnifying mirror that enlarges and reflects the display light emitted by the display device 10. For example, an aspherical (free-form) mirror is used as the reflector 40. The display light projected onto the projection target Rwf is reflected by the projection target Rwf to an eye point EP or an eye box EB, so that an occupant can visually perceive the display light as a virtual image ( Fig. 1) The eye point EP indicates the position of an occupant's eyes within the vehicle interior. The eye box EB indicates the area of ​​eye point EP in which the virtual image is visually perceptible.

[0013] The vehicle display device 1 includes a control unit 50 which controls the display light depending on the eye point EP or the eye box EP of an occupant ( Fig. 1).

[0014] The vehicle display device 1 further comprises the housing 61, inside which at least the display device 10 and the reflector 40 are accommodated, and a transparent cover 62, which closes the opening 61a of the housing 61 ( Fig. 1) In the vehicle display device 1, the display light reflected by the reflector 40 is emitted through the cover 62 to the outside of the housing 61 and projected onto the external projection target Rwf. The vehicle display device 1 shown here is mounted in an instrument panel Pi in the vehicle interior such that the cover 62 is exposed, and projects the display light reflected by the reflector 40 onto the projection target Rwf ( Fig. 1) Then the vehicle display device 1 reflects the display light from the projection target part Rwf to the eye point EP or the eye point EB.

[0015] In this context, the projection target Rwf is the windshield (in this case, a front windshield Wf) or a part thereof. Furthermore, the projection target Rwf can be configured as a semi-mirror that receives indicator light from the reflector 40 at a reflective surface, reflects it to the eye point EP or the eye box EB, and emits light from outside the vehicle to the occupant. For example, the projection target Rwf configured as a semi-mirror is formed from a semi-transparent film that follows the curved shape of the windshield (the front windshield Wf) and is bonded to the inner surface of the windshield inside the vehicle using an adhesive.Alternatively, the projection target element Rwf, designed as a semi-mirror, can also be formed from a semi-transparent film that follows the curved shape of the windshield (the front windshield Wf) and is enclosed within the laminated glass of the windshield together with an intermediate film. Furthermore, the projection target element Rwf, designed as a semi-mirror, can also be a semi-transparent coating applied to the inner surface of the windshield (the front windshield Wf) inside the vehicle. Finally, the projection target element Rwf can also be a combiner that covers the inner surface of the front windshield Wf from inside the vehicle.

[0016] The rear lighting unit 20 comprises a light source 21, a control board 22 for the light source 21 and a heat sink 23 that dissipates the heat generated by the light source 21 ( Fig. 2) The light source 21 is a light-emitting element. Here, an LED element is used as the light-emitting element. The light source 21 is arranged at several positions between a first light source position, which is associated with the radiant light emitted from a first edge (upper edge in the vertical direction) of a radiating surface 20a described below, and a second light source position, which is associated with the radiant light emitted from a second edge (lower edge in the vertical direction) of the radiating surface 20a. The backlighting unit 20 described here is equipped with the several vertically arranged light sources 21. The control board 22 electrically connects the light source 21 to a power source via a wiring pattern.On a circuit board surface 22a of the control board 22 described here, the multiple light sources 21 are arranged at equal intervals in the vertical direction and in the direction perpendicular to the vertical direction (. Fig. 2 and Fig. 3).

[0017] Furthermore, the backlighting unit 20 comprises a condenser lens 24, which is arranged such that it faces the circuit board surface 22a of the control board 22 and concentrates light emitted by the light source 21 arranged between the circuit board surface 22a and the condenser lens 24 (hereinafter referred to as "source light"), and a field lens 25, which scatters and distributes the source light concentrated by the condenser lens 24.

[0018] The condenser lens 24 is a lens element made of glass or a transparent resin that concentrates the source light from the light source 21. For the condenser lens 24 described here, for example, a condenser lens is used in which a lens element 24a is arranged for each light source 21 such that it faces the light source 21. The lens element 24a has an incident surface that receives the light from the light source 21 and an emissive surface that emits the light from the incident surface, and is designed as a plano-convex lens with an incident surface shaped as a flat plane and an emissive surface shaped as a convex curved plane.

[0019] The field lens 25 is a lens element made of glass or a transparent resin, aligned in the direction of motion of the source light emitted by the condenser lens 24, and arranged between the condenser lens 24 and the display unit 30. The field lens 25 has an incident surface that receives the source light from the light source 21 via the condenser lens 24, and an emissive surface that emits the source light incident from the incident surface. For example, a Fresnel lens is used for the field lens 25 described here.

[0020] In the rear illumination unit 20, the emission surface of the field lens 25 serves as the radiation surface 20a ( Fig. 2) The direction of movement of the source light from each light source 21 through the condenser lens 24 is aligned by the field lens 25, and the source light is scattered and distributed by the radiation surface 20a. In the backlighting unit 20, for example, the direction perpendicular to the circuit board surface 22a of the control board 22 or the direction perpendicular to the incidence surface of the lens element 24a of the condenser lens 24 corresponds to the direction of the optical axis. The backlighting unit 20 illuminates the display unit 30 with the source light emitted by the radiation surface 20a as the radiation light.

[0021] The display unit 30 causes the radiant light from the radiating surface 20a of the rear illumination unit 20 to fall on a radiating target surface 30a on the rear, and causes the display light as the display information to be emitted from an emission surface 30b on the front to the reflector 40 ( Fig. 2) The display unit 30 allows the radiant light incident from the radiating surface 20a to pass through the emissive surface 30b and be emitted as the display light. The display unit 30 described here uses a transparent thin-film transistor (TFT) liquid crystal display. The display unit 30 is controlled by the control unit 50 to display the information. For example, image information elements such as letters, numbers, and diagrams are displayed as information.

[0022] The display unit 30 is inclined relative to the radiation surface 20a such that, between the radiation surface 20a and the reflector 40 in the direction of the optical axis of the backlighting unit 20 with respect to the radiation surface 20a, the distance between the first edges, which define the lower edges of the virtual image in the vertical direction on the radiation surface 20a, and the radiation target surface 30a is greater than the distance between the second edges, which define the upper edges of the virtual image in the vertical direction on the radiation surface 20a, and the radiation target surface 30a. In this embodiment, the radiation surface 20a and the radiation target surface 30a are arranged such that their corresponding vertically upper sides are the first edges and their corresponding vertically lower sides are the second edges.The display unit 30 is inclined relative to the radiation surface 20a, such that between the radiation surface 20a and the reflector 40 the distance between the upper edges in the direction vertically upwards of the radiation surface 20a and the radiation target surface 30a is greater than the distance between the lower edges in the direction vertically downwards of the radiation surface 20a and the radiation target surface 30a (. Fig. 2) As described here, the display unit 30 and the emission surfaces 20a of the rear lighting unit 20 are each inclined such that their upper edges are inclined vertically upwards towards the front of the vehicle and their lower edges act vertically downwards as the pivot point of the rotational movement. In the vehicle display device 1, the inclination angle of the display unit 30 is greater than the inclination angle of the emission surface 20a of the rear lighting unit 20, so that the optical axis of the rear lighting unit 20 intersects the emission target surface 30a and the emission surface 30b of the display unit 30, but is not perpendicular to them.

[0023] To avoid glare from external light, in particular, when the external light entering through the opening 61a of the housing 61 is reflected by the reflector 40 and reaches the emission surface 30b, the display unit 30 described here is inclined relative to the radiation surface 20a of the backlighting unit 20 to prevent the external light reflected by the emission surface 30b from being reflected back to the reflector 40. For example, in this case, the external light reflected by the emission surface 30b is directed towards a bottom wall of the housing 61 ( Fig. 1).

[0024] In this way, in the vehicle display device 1, the direction of the optical axis of the rear lighting unit 20 intersects the direction perpendicular to the radiation target surface 30a and the emission surface 30b of the display unit 30. Therefore, in the display unit 30, the absolute value of an emission angle θ ( Fig. 2) the indicator light relative to a reference emission direction (in this case, the orthogonal direction to the emission surface 30b) of the indicator light emitted by the emission surface 30b is greater at the upper edge than at the lower edge (θ2 > θ1). For example, in the indicator unit 30 described here, the indicator light is emitted from the lower edge of the emission surface 30b with a negative emission angle θ relative to the reference emission direction, and the absolute value of the negative emission angle θ of the indicator light relative to the reference emission direction temporarily decreases as it moves from this lower edge to the upper edge, with the indicator light being emitted in the reference emission direction (θ = 0) at a certain position.Then, in the display unit 30 described here, a positive emission angle θ of the display light relative to the reference emission direction increases as it moves from the positive / negative switching position (θ = 0) to the upper edge, whereby at a certain position the absolute value of this positive emission angle θ becomes equal to the absolute value of the negative emission angle θ at the lower edge, and wherein the positive emission angle θ of the display light relative to the reference emission direction becomes even larger as it moves from this position to the upper edge.

[0025] In this case, the display unit 30 has the highest light transmittance T(θ) when the emission angle θ of the display light is zero degrees relative to the reference emission direction, with the light transmittance T(θ) decreasing as the emission angle θ of the display light becomes larger relative to the reference emission direction, regardless of whether it is positive or negative ( Fig. 4) In other words, the display unit 30 has the highest luminance L(θ) when the emission angle θ of the display light is zero degrees relative to the reference emission direction, with the luminance L(θ) decreasing as the emission angle (θ) of the display light increases relative to the reference emission direction, regardless of whether it is positive or negative. Thus, if in this display unit 30 the luminance of the light emitted from the radiating surface 20a of the backlighting unit 20 and incident on the radiating target surface 30a is uniform over the entire surface of the radiating target surface 30a, the luminance L(θ) will be lower at the upper edge, with the distance between the radiating target surface 30a and the radiating surface 20a being greater at the lower edge than at the upper edge, resulting in a non-uniformity of the luminance ( Fig. 5) If, for example, in this display unit 30, a first region, in which the absolute value of the emission angle θ of the display light is kept below a certain value relative to the reference emission direction, and a second region, in which the absolute value of the emission angle θ exceeds a certain value and becomes even larger, are mixed at the first emission surface 30b, a luminance unevenness occurs between the first and second regions of such magnitude that it causes an unpleasant sensation in the virtual image display. In this case, the region from the lower edge to just before the upper edge of the emission surface 30b constitutes the first region, and the luminance L(θ) at the upper edge of the emission surface 30b, which forms the second region, is significantly lower than at the first region.

[0026] In this way, the control unit 50 controls the backlighting unit 20 to reduce the luminance unevenness in the display unit 30. The control unit 50 controls the backlighting unit 20 and provides for a higher luminance at the first edge than at the second edge (i.e., higher at the top edge in the vertical direction than at the bottom edge in the vertical direction) of the light emitted by the emission surface 30b of the display unit 30.In other words, the control unit 50 provides the luminance of the light emitted by the radiating surface 20a of the rear illumination unit 20 and incident on the radiating target surface 30a of the display unit 30 to be higher at the first edge than at the second edge of the radiating surface 30a (i.e. higher at the upper edge in the vertical direction than at the lower edge in the vertical direction) and provides the luminance L(θ) to be higher at the first edge than at the second edge of the emission surface 30b of the display unit 30 (i.e. higher at the upper edge in the vertical direction than at the lower edge in the vertical direction) in order to reduce the unevenness of the luminance of the display light emitted by the emission surface 30b over the entire emission surface 30b.

[0027] In particular, the control unit 50 increases the luminance of the light source 21 that is located closer to the first light source position (i.e., at the top edge in the vertical direction) in the arrangement direction of the light source in the backlighting unit 20, compared to the luminance of the light source 21 that is located on the side of the second light source position (i.e., vertically below it), so that the luminance of the light emitted from the radiating surface 20a of the backlighting unit 20 and incident on the radiating target surface 30a of the display unit 30 is provided higher at the first edge than at the second edge (i.e., higher at the top edge in the vertical direction than at the bottom edge in the vertical direction).For example, the control unit 50 calculates the luminance L(θ) of the control target position (in this case, the upper edge of the emission surface 30b) using the following formula 1, based on the luminance L(θmin) and the transmittance T(θmin) at the position where the absolute value of the emission angle θ of the indicator light relative to the reference emission direction is minimal. The control unit 50 then controls the luminance of the light source 21 in accordance with a control target position (in this case, the upper edge of the emission surface 30b) based on the calculated value of the luminance L(θ) for an approximation of the luminance L(θ). L(θ)={T(θmin)−T(θ)}*L(θmin)

[0028] In this way, the vehicle display device 1 of this embodiment provides the luminance L(θ) at the first edge of the emission surface 30b of the display unit 30 to be higher than at the second edge (i.e. higher at the upper edge in the vertical direction than at the lower edge in the vertical direction) in order to reduce the unevenness of the luminance of the display light emitted by the emission surface 30b over the entire emission surface 30b and thereby improve the visibility of the virtual image display.

[0029] Incidentally, strictly speaking, in display unit 30 the absolute value of the emission angle θ of the display light relative to the reference emission direction differs at each position on the emission surface 30b, so that a deviation in luminance L(θ) occurs at each position. For this reason, even at positions where the effect on the visibility of the virtual image display is small, a luminance irregularity actually occurs in display unit 30.

[0030] Therefore, the emission area 30b of the display unit 30 is initially divided into a plurality of subdivided areas. For example, the emission area 30b is divided into subdivided areas for each light source 21, i.e., into a plurality of subdivided areas arranged at equal intervals in the vertical direction and in the direction perpendicular to the vertical direction. Then, the control unit 50 calculates the luminance L(θ) of each subdivided area, except for the subdivided area where the absolute value of the emission angle θ of the display light relative to the reference emission direction is minimal, based on the formula 1 mentioned above. Subsequently, the control unit 50 controls the luminance of the light source 21 in accordance with the subdivided control target area, based on the calculated value of the luminance L(θ) for each subdivided area, to approximate the luminance L(θ).In this way, the vehicle display device 1 can further reduce the unevenness of the luminance of the display light emitted by the emission surface 30b of the display unit 30 over the entire emission surface 30b and thereby further improve the visibility of the virtual display image.

[0031] Furthermore, the control unit 50 can also adjust the luminance of the radiant light incident on the radiation target surface 30a of the display unit 30 from the radiation surface 20a of the rear lighting unit 20 for each subdivided area as a function of the luminance of the external light for each subdivided area, in order to reduce the unevenness of the luminance of the display light emitted from the emission surface 30b of the display unit 30. In this case, the vehicle display device 1 is equipped with a light meter for each subdivided area to measure the luminance of the external light reflected by the reflector 40.Alternatively, the vehicle display device 1 measures the luminance of the external light entering through the opening 61a of the housing 61 using a light meter and causes the control unit 50 to estimate the luminance of the external light for each subdivided area based on the measurement result obtained.

[0032] For example, the control unit 50 is equipped with map data of a luminance correction value L(S) corresponding to the luminance of the external light ( Fig. 6) is provided and calculates the luminance correction value L(S) corresponding to the luminance of the external light for each subdivided area from the map data. For example, the luminance correction value L(S) is used as a correction coefficient and the luminance L(θ) of the subdivided control target area is calculated from the following formula 2. L(θ)={T(θmin)−T(θ)}*L(θmin)*L(S)

[0033] The control unit 50 controls the luminance of the light source 21 in accordance with the subdivided control target range based on the calculated value of the luminance L(θ), so that the luminance of the light source 21 approaches the luminance L(θ). In this way, the vehicle display device 1 can eliminate the effects of external light and reduce the unevenness of the luminance of the display light emitted by the emission surface 30b of the display unit 30 across the entire emission surface 30b, thereby further improving the visibility of the virtual display image. [Modifications]

[0034] A vehicle display device 2 of this modification differs from the vehicle display device 1 of the previously described embodiment in that the mounting angle of the display device 10 is different and an additional reflector is added ( Fig. 7)

[0035] The vehicle display device 2 comprises, as reflecting elements, a first reflecting element 141, which reflects the display light emitted by the display device 10, and a second reflecting element 142, which reflects the display light reflected by the first reflecting element 141 and causes the reflected light to be projected through the opening 61a of the housing 61 onto the projection target part Rwf ( Fig. 7) The first reflecting element 141 is a folding mirror. And the second reflecting element 142 is a magnifying mirror, similar to the reflecting element 40 of the embodiment described above.

[0036] The display unit 30 of the display device 10 of this modification is inclined relative to the radiation surface 20a such that the distance between the first edges, which define the lower edges of the virtual image in the vertical direction on the radiation surface 20a, and the radiation target surface 30a is greater than the distance between the second edges, which define the upper edges of the virtual image in the vertical direction on the radiation surface 20a, and the radiation target surface 30a, similar to the display device 10 of the embodiment. However, the display device 10 of the embodiment is arranged such that the display light is emitted from the emission surface 30b of the display unit 30 towards the front of the vehicle.In contrast, the display device 10 of this modification is arranged such that the display light is emitted from the emission surface 30b of the display unit 30 either to the vertically upper side (i.e., to the upper side of the vehicle) or to the vertically lower side (i.e., to the lower side of the vehicle). Therefore, the display device 10 of this modification uses the following configuration.

[0037] The radiation surface 20a and the radiation target surface 30a of this modification are arranged such that one edge side in a direction perpendicular to the vertical direction corresponds to a first edge and the other edge side in a direction perpendicular to the vertical direction corresponds to a second edge. Furthermore, the light source 21 of this modification is arranged at several positions between a first light source position, which is associated with the radiation light from the first edge of the radiation surface 20a of this modification, and a second light source position, which is associated with the radiation light from the second edge of the radiation surface 20a.The display unit 30 is inclined relative to the radiation surface 20a such that the distance between the other edge on the radiation surface 20a and the other edge on the radiation target surface 30a between the radiation surface 20a and the first reflecting element 141 is greater than the distance between one edge on the radiation surface 20a and one edge on the radiation target surface 30a.

[0038] In this example, the indicator light is emitted vertically upwards (i.e., towards the top of the vehicle) from the emission surface 30b of the display unit 30 to create a virtual image in front of the vehicle ( Fig. 7) The radiation surface 20a and the radiation target surface 30a described here are therefore each arranged such that the first edge is located on the front side of the vehicle and the second edge is located on the rear side of the vehicle ( Fig. 8) Furthermore, the rear lighting unit 20 described here comprises a plurality of light sources 21, which are arranged in the front-to-rear direction of the vehicle ( Fig. 8) The display unit 30 described here is inclined relative to the radiation surface 20a, such that the distance between the edges of the radiation surface 20a and the radiation target surface 30a on the front side of the vehicle is greater than the distance between the edges of the radiation surface 20a and the radiation target surface 30a on the rear side of the vehicle ( Fig. 7).

[0039] The control unit 50 of this modification controls the rear lighting unit 20 and perceives the luminance of the radiant light incident from the radiating surface 20a of the rear lighting unit 20 onto the radiating target surface 30a of the display unit 30 as higher at one edge than at the other edge (i.e., higher at the edge on the front side of the vehicle than at the edge on the rear side of the vehicle) in order to reduce the unevenness of the luminance of the display light emitted from the emission surface 30b of the display unit 30. In other words, the control unit 50 perceives the luminance of the radiant light incident from the radiating surface 20a of the rear lighting unit 20 onto the radiating target surface 30a of the display unit 30 as higher at one edge than at the other edge of the radiating target surface 30a (i.e., higher at the edge on the front side of the vehicle than at the edge on the rear side of the vehicle).higher at the edge on the front side of the vehicle than at the edge on the rear side of the vehicle) and provides the luminance L(θ) at one edge higher than at the other edge of the emission surface 30b of the display unit 30 (i.e. higher at the edge on the front side of the vehicle than at the edge on the rear side of the vehicle) in order to reduce the unevenness of the luminance of the display light emitted by the emission surface 30b over the entire emission surface 30b.

[0040] In particular, the control unit 50 of this modification increases the luminance of the light source 21 that is located closer to the first light source position (i.e., on the front side of the vehicle) in the arrangement direction of the light sources 21 in the rear lighting unit 20, compared to the luminance of the light source 21 that is located at the second light source position (i.e., on the edge on the rear side of the vehicle), in order to provide the luminance of the radiant light incident from the radiant surface 20a of the rear lighting unit 20 on the radiant target surface 30a of the display unit 30 at one edge higher than at the other edge (i.e., higher at the edge on the front side of the vehicle than at the edge on the rear side of the vehicle).

[0041] The vehicle display device 2 of this modification can also achieve similar effects to the vehicle display device 1 of this embodiment if the first reflector (folding mirror) 141 is arranged between the display device 10 and the second reflector (magnifying mirror) 142 as described above. List of reference symbols 1, 2 Vehicle display device 10 Display device 20 Rear lighting unit 20a Radiation area 21 Light source 30 display units 30a Radiation target area 30b Emission area 40 Reflection element 50 control unit 61 cases 61a Opening 141 first reflection element 142 second reflection element EB Eyebox EP Focus RWF projection target part QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2019 - 101 056 A

[0003]

Claims

[1] Vehicle display device, comprising: a case, a display device which is arranged in the housing and configured to emit display information as a display light which is visually perceived by an occupant in a vehicle interior as a virtual image, at least one reflector configured to reflect the indicator light emitted by the display device in the housing and to cause the indicator light to be projected through an opening in the housing onto a projection target in the vehicle interior, and a control unit configured to control the display light depending on an occupant's eye point or an eye box, which is an area of ​​eye points that allows visual perception of the virtual image, wherein the display device comprises a backlighting unit configured to scatter and distribute the light from a light source from a radiating surface, and a translucent, plate-shaped display unit configured to cause radiant light incident from the radiating surface onto a radiating target surface to be transmitted and emitted from an emissive surface as the display light, wherein the display unit is inclined relative to the radiating surface such that the distance between the radiating surface and the reflector, which is arranged in the direction of an optical axis of the backlighting unit with respect to the radiating surface, is greater than the distance between the second edges, which define the upper edges of the virtual image in the vertical direction on the radiating surface and the radiating target surface, and The control unit controls the backlighting unit to provide a higher luminance of the radiant light incident on the radiant target surface from the radiating surface at the first edge than at the second edge, thereby reducing the unevenness of the luminance of the display light to be emitted from the emission surface of the display unit. [2] Vehicle display device according to claim 1, wherein: the light source is arranged at a multitude of positions between a first light source position associated with the radiant light from the first edge of the radiant surface and a second light source position associated with the radiant light from the second edge of the radiant surface, and The control unit increases the luminance of the light source that is located closer to the first light source position in an arrangement direction of the light sources, compared to the luminance of the light source that is located at the second light source position, in order to provide the luminance of the radiant light incident from the radiation surface onto the radiation target surface to be higher at the first edge than at the second edge. [3] Vehicle display device according to claim 1 or 2, wherein the display unit is inclined relative to the radiating surface, such that when external light entering through the opening of the housing is reflected by the reflecting element and reaches the emission surface, it is prevented that the external light reflected by the emission surface is directed back towards the reflecting element. [4] Vehicle display device according to claim 3, wherein the control unit adjusts the luminance of the radiant light incident from the radiating surface on the radiant target surface for each subdivided area obtained by subdividing the emission surface of the display unit into a plurality of areas, depending on the luminance of the external light for each of the subdivided areas, in order to reduce any unevenness in the luminance of the display light to be emitted from the emission surface of the display unit. [5] Vehicle display device according to claim 1 or 2, wherein: the reflector is provided as a single reflector between the display device and the housing, the radiation surface and the radiation target surface are each arranged in such a way that an upper side corresponds to the first edge in the vertical direction and a lower side corresponds to the second edge in the vertical direction, the display unit is inclined relative to the radiation surface such that the distance between the upper edges on the top side in the vertical direction on the radiation surface and the radiation target surface is greater than the distance between the lower edges on the bottom side in the vertical direction on the radiation surface and the radiation target surface, and The control unit controls the rear lighting unit to ensure that the luminance of the radiant light emitted from the radiation surface to the radiation target surface is higher at the upper edge than at the lower edge. [6] Vehicle display device according to claim 1 or 2, wherein: The reflector comprises a first reflector configured to reflect the display light emitted by the display device, and a second reflector configured to reflect the display light reflected by the first reflector and to cause the display light to be projected through the opening of the housing onto the projection target part. the radiation surface and the radiation target surface are each arranged such that one edge in a direction orthogonal to the vertical direction corresponds to the first edge and the other edge in the orthogonal direction corresponds to the second edge, the display unit is inclined relative to the radiation surface such that the distance between one edge on the radiation surface and one edge on the radiation target surface is greater than the distance between the other edge on the radiation surface and the other edge on the radiation target surface, and The control unit controls the rear lighting unit to ensure that the luminance of the radiant light emitted from the radiation surface to the radiation target surface is higher at one edge than at the other edge.

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