DE102020101601A1 - Automotive comfort projection device - Google Patents

Abstract

The invention relates to a motor vehicle comfort projection device with a light source and a projection lens. The invention is characterized in that the projection device has a conical light guide, a converging lens serving as a field lens and a liquid crystal matrix display as the imaging element and a projection lens set up for imaging the liquid crystal display.

Description

The present invention relates to a motor vehicle comfort projection device according to the preamble of claim 1. Such a device is from US Pat DE 102 15 893 C1 famous.

The spread of digital technology in vehicles means that functions that have been established for decades, such as vehicle interior lighting, are to be controlled adaptively and without contact in the future.

It is not just a matter of adapting the illuminated area of the passenger compartment in terms of shape, size and color temperature to the passenger's wishes over a wide range; The projecting of greeting animations and display functions should also help to improve the interaction between passenger and vehicle and to create a pleasant and comfortable atmosphere for the traveler in every respect.

Various forms of video projectors in LCD (LCD: Liquid Crystal Display) and DLP (DLP: Digital Light Processing) technology are known from the prior art, which are, however, hardly suitable for use in terms of system costs and the possibilities for miniaturization digital comfort lighting suitable for motor vehicles. Although LCD projectors are superior to DLP systems suitable for automotive applications in terms of system costs, the effort for color projection is also considerable here, since separate illumination beam paths usually have to be provided for each primary color, which are then brought together via dichroic mirrors .

A further simplification would be the use of color LCD displays, which provide pixels with corresponding color filters for each basic color and only have to be backlit in white. However, these color filters lead to high power losses, which is why such projectors are not only inefficient and faint, but also suffer from a high level of self-heating of the LCD display, which is difficult to cool passively and severely restricts the working range of the system.

Against this background, the object of the invention is to provide a motor vehicle comfort projection device that can illuminate a desired illumination area in terms of shape, size and color temperature as a color video projection system.

The device should have a very broadband light source in order to ensure good color rendering. In order to be able to replace conventional reading lamps, the device must be capable of being greatly miniaturized, have good efficiencies and, moreover, be inexpensive.

These requirements are solved with the sum of the features of claim 1.

The present invention differs from the prior art mentioned at the beginning in that the projection device has a conical light guide, a converging lens serving as a field lens, a liquid crystal matrix display as the imaging element and a projection lens set up for imaging the liquid crystal display.

The motor vehicle comfort projection device according to the invention is suitable as a digitally controllable motor vehicle interior lighting device. The motor vehicle comfort projection device according to the invention can, however, also be set up to project moving images into a lighting zone outside the motor vehicle, for example to greet the driver (welcome carpet) when approaching the motor vehicle, etc. Because of its small size, the motor vehicle comfort Integrate the projection device in a simple manner in a door or in an exterior mirror of the motor vehicle. Compared to multi-Led solutions, the motor vehicle comfort projection device according to the invention offers far better image quality with significantly higher color rendering values and with the possibility of projecting color videos. The liquid crystal projector described can be manufactured particularly inexpensively (inexpensive display, relatively few components).

A preferred embodiment is characterized in that the light source has LEDs with at least two different light colors.

It is also preferred that the light colors are cold white and yellow. It is further preferred that the light colors are blue, red and green. Another preferred embodiment is characterized in that the light colors are blue, red, green and white.

It is also preferred that the light colors are additionally yellow and / or orange and / or cyan and / or violet.

It is further preferred that LED chips which emit blue light are used to generate the different colors, the light of which is converted into the respective colors by appropriate phosphor layers.

Another preferred embodiment is characterized in that the LEDs can be controlled independently or separately according to color.

It is also preferred that the conical light guide is a truncated pyramid.

Another preferred embodiment is characterized in that the cross section of the light guide, which is perpendicular to the main direction of propagation in the light guide, is rectangular or square.

It is also preferred that the light guide consists of glass, in particular an inorganic crown glass.

It is further preferred that the light entry and light exit surfaces of the light guide are parallel to one another.

Another preferred embodiment is characterized in that the length of the light guide in the main direction of propagation of the light is 2 to 8 times the diagonal of the light exit surface of the light guide.

It is also preferred that mutually corresponding side lengths of the light entry surface and light exit surface differ by an integer factor, the factor being able to have the values 2 to 8 and the light exit side being longer than the light entry side corresponding to it.

It is further preferred that the light guide has two planes of symmetry which contain the optical axis and which are each perpendicular to two side faces and to the light entry face and to the light exit face.

Another preferred embodiment is characterized in that the light entry surface and the light exit surface of the light guide are coated with an anti-reflective coating.

It is also preferred that the field lens is arranged upstream of the light flow directly in front of the liquid crystal display between the light guide and the liquid crystal display.

Another preferred embodiment is characterized in that the field lens is arranged directly downstream of the light flow from the liquid crystal display between the display and the projection lens.

It is also preferred that the field lens is a Fresnel lens.

It is further preferred that the Fresnel zones of the Fresnel lens point in the direction of the incident light. The Fresnel zones (or Fresnel surfaces) are areas on a non-smooth light entry surface of the Fresnel lens. Another preferred embodiment is characterized in that the Fresnel surfaces are conical surfaces, spherical surfaces or aspherical surfaces with a common axis of rotation.

It is also preferred that the Fresnel lens consists of glass, in particular an organic glass.

It is further preferred that the Fresnel lens consists of PMMA (polymethyl methacrylate), PC (polycarbonate), PEI (polyetherimide), COC (cyclo-olefin copolymer) or COP (cyclo-olefin polymer).

Another preferred embodiment is characterized in that the focal length of the field lens is greater than or equal to the focal length of the projection objective.

It is also preferred that the optical surfaces of the field lens are coated with an anti-reflective coating.

It is further preferred that the liquid crystal display has a matrix of liquid crystal cells, which rotate the polarization direction of the transmitted light voltage-dependently in each liquid crystal cell, and that a linear polarization filter is arranged upstream of the light flow (polarizer) and downstream of the light flow (analyzer) of the liquid crystal cells, the polarization filter so are rotated by 90 ° in relation to each other so that light whose polarization direction has not been rotated in the liquid crystal cells is absorbed in the subsequent polarization filter (analyzer).

It is also preferred that linear polarization filters aligned in parallel are arranged on both sides of the liquid crystal cells, so that only light is transmitted whose polarization direction has not been rotated in the liquid crystal cells. This results in a higher light yield with, however, lower contrast.

Another preferred embodiment is characterized in that at least one of the polarization filters is a brightness enhancement film, in particular the polarization filter arranged upstream of the liquid crystal cells for the light flow.

It is further preferred that at least one polarization filter is designed as a reflective wire grid polarizer, in particular the polarization filter arranged upstream of the liquid crystal cells.

It is also preferred that the polarization filters are combinations of in the direction of the luminous flux reflecting and absorbing polarization filters arranged one behind the other.

It is further preferred that the projection objective is a converging lens, in particular an aspherical converging lens.

It is also preferred that the projection objective is a refractive-diffractive hybrid lens.

It is further preferred that the projection lens is a Steinheil periscope lens, that is to say a wide-angle lens made up of two meniscus lenses which are arranged with their concave sides to one another, the meniscus lenses in particular being aspherical meniscus lenses.

Another preferred embodiment is characterized in that all or individual lenses of the objective are made of plastic, in particular of PMMA, PC, PEI, COC or COP.

It is also preferred that the lenses of the objective are coated.

It is further preferred that a deflecting mirror which folds the beam path is arranged between the liquid crystal display and the projection lens and bends the beam path at right angles.

It is also preferred that the deflection mirror is integrated into a projection lens as a reflective surface.

Further advantages emerge from the following description, the drawings and the subclaims. It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or on their own, without departing from the scope of the present invention.

Embodiments of the invention are shown in the drawings and are explained in more detail in the following description.

• 1 ein Ausführungsbeispiel einer erfindungsgemäßen Kraftfahrzeugkomfort-Projektionsvorrichtung;
• 2 eine perspektivische Darstellung eines Lichtleitstabes mit einer Lichtquelle;
• 3 Einzelheiten aus der 2 in Form von alternativen Anordnungen von Leuchtdioden;
• 4 eine Draufsicht auf eine quadratische Anordnung von Licht verschiedener Farbe, emittierenden Leuchtdioden;
• 5 eine Draufsicht auf eine Anordnung von zwei gelbes Licht emittierenden Leuchtdioden und von zwei weißes Licht emittierenden Leuchtdioden;
• 6 eine Draufsicht auf eine Anordnung von sechs Leuchtdioden;
• 7 eine Kombination von sieben Leuchtdioden;
• 8 eine Draufsicht auf die Lichtaustrittsfläche eines Lichtleitstabes mit rechteckigem, hier insbesondere quadratischem Querschnitt;
• 9 einen Schnitt durch den Lichtleitstab aus der 8, der in einer ersten Symmetrieebene des Lichtleitstabes liegt;
• 10 einen Schnitt durch den Lichtleitstab aus der 8, der in einer zweiten Symmetrieebene des Lichtleitstabes liegt;
• 11 eine perspektivische Ansicht des Lichtleitstabes aus den 8 bis 10;
• 12 ein Ausführungsbeispiel einer Kraftfahrzeugkomfort-Projektionsvorrichtung mit einem zusätzlichen Umlenkspiegel.
• 13 ein Ausführungsbeispiel einer Kraftfahrzeugkomfort-Projektionsvorrichtung mit einem anders angeordneten Umlenkspiegel.

Show, each in schematic form:

• 1 an embodiment of a motor vehicle comfort projection device according to the invention;
• 2 a perspective view of a light guide rod with a light source;
• 3 Details from the 2 in the form of alternative arrangements of light emitting diodes;
• 4th a plan view of a square arrangement of light of different colors, emitting light-emitting diodes;
• 5 a plan view of an arrangement of two yellow light-emitting light-emitting diodes and two white light-emitting light-emitting diodes;
• 6th a plan view of an arrangement of six light emitting diodes;
• 7th a combination of seven light emitting diodes;
• 8th a plan view of the light exit surface of a light guide rod with a rectangular, here in particular a square cross-section;
• 9 a section through the light guide rod from 8th , which lies in a first plane of symmetry of the light guide rod;
• 10 a section through the light guide rod from 8th , which lies in a second plane of symmetry of the light guide rod;
• 11 a perspective view of the light guide rod from FIG 8th until 10 ;
• 12th an embodiment of a motor vehicle comfort projection device with an additional deflecting mirror.
• 13th an embodiment of a motor vehicle comfort projection device with a differently arranged deflecting mirror.

In detail, the 1 an automotive comfort projection device 10 who have favourited a light source 12th , a conical light guide 14th , one as a field lens 16 serving converging lens and a liquid crystal display 18th as an imaging element and one for imaging the liquid crystal display 18th set up projection lens 20th having.

The light source 12th is set up to emit light that contains components of at least two different light colors. The light source 12th has, for example, several light-emitting diodes that differ in their light color.

The light source 12th forms together with the conical light guide 14th a mixing device with which the differently colored light components are mixed completely evenly, which means that different lighting colors are used to illuminate the liquid crystal display, depending on the light-emitting diodes used and their respective control 18th let generate.

The liquid crystal display 18th is so between the light exit surface of the conical light guide 14th and the projection lens 20th arranged that the projection lens 20th a picture of the Liquid crystal displays 18th into the lighting zone of the motor vehicle comfort projection device 10 projected. The lighting zone can be a vehicle interior, but it can also be an area in the surroundings of the motor vehicle, for example an entry area outside a vehicle door. The lighting zone can then form a carpet of light. The field lens 16 is immediately in front of or behind the liquid crystal display 18th arranged.

As 1 shows, the field lens is arranged between the light guide rod and the projection objective and directly upstream of the imaging liquid crystal display, that is, between the light guide rod and the liquid crystal display. As an alternative to this, the field lens can also be arranged downstream of the light flow from the imaging liquid crystal display, that is to say between the liquid crystal display and the projection objective.

The field lens is preferably a Fresnel lens. The convex Fresnel zones point in the direction of the incident light. The Fresnel zone surfaces are conical surfaces, spherical surfaces or aspherical surfaces that have a common axis of rotation. The material of the Fresnel lens is preferably glass, in particular an organic glass. In an alternative embodiment, the Fresnel lens consists of PMMA, PC, PEI, COC or COP. Their focal length is preferably equal to or greater than the focal length of the projection lens. The optical surfaces of the field lens are preferably coated with an anti-reflective coating

The function of the field lens 16 consists in that from the light exit surface of the conical light guide 14th divergent (opening angle greater than 0 °) emerging light in the entrance pupil of the light flow downstream from the liquid crystal display 18th arranged projection lens 20th to bundle. The field lens 16 thus acts as a condenser.

The motor vehicle comfort projection device is thus distinguished 10 not only through a perfect mix of light and a completely homogeneously illuminated image field, the combination of a conical light guide 14th and field lens 16 In addition, it enables outstanding optical efficiency. Over 90% of the emitted light can be used for projection.

By focusing directly on the pupil of the projection lens 20th can for the projection lens 20th comparatively inexpensive, faint optics are used, which also offer a good depth of field due to the low aperture ratio.

The automobile comfort projection device 10 further comprises a first polarizing filter 19th (Polarizer) and a second polarizing filter 21 (Analyzer). The first polarizing filter 19th is upstream of the liquid crystal display 18th arranged. The second polarizing filter 21 is downstream of the liquid crystal display 18th arranged.

The two polarizing filters 19th , 21 are arranged in a first alternative in such a way that their polarization directions (transmission directions) cross each other. The directions of polarization preferably enclose a right angle. In a second alternative are the two polarization filters 19th , 21 arranged so that their polarization directions are parallel to each other.

In an alternative there is at least one of the two polarizers 19th , 21 a wire grid polarizer. Another alternative is the polarizer 19th a brightness enhancement film. The two polarizers 19th , 21 are preferred with the liquid crystal display 18th glued so that the liquid crystal display 18th between the two polarizers 19th , 21 is arranged. Instead of a polarization filter 19th , 21 a combination of a reflective and an absorbing polarizing filter can also be used. Each of the two polarizing filters 19th , 21 only allows light of a certain polarization direction to pass.

The statements on the polarizers are intended for all exemplary embodiments, even if the polarizers 19th , 21 for the sake of clarity, for example in the 12th and 13th are not shown.

The liquid crystal display 18th As an imaging element, it consists of many transparent cells, which are arranged next to one another in rows and columns and filled with a liquid crystal, to which an electric field can be applied. In order to achieve good transmission, the liquid crystal display does not have a color filter.

As each of the two polarizing filters 19th , 21 only allows light of a certain polarization direction to pass, this is between the two polarization filters 19th , 21 horizontal liquid crystal display 18th illuminated with polarized light.

The polarization direction of the incident light in the liquid crystal display can be determined as a function of the voltage applied to the individual cells 18th can be rotated individually for each cell. Depending on the polarization direction of the liquid crystal cells, a different amount of light passes through the polarization filter arranged downstream of the liquid crystal display 21 (Analyzer), and cells of different lightness result depending on the applied electrical voltage. In this way can be found on the light exit surface of the liquid crystal display 18th create colored images.

With an arrangement of the polarization filter 19th , 21 with intersecting polarization directions, light whose polarization direction has not been rotated in the liquid crystal cells is transmitted in the subsequent polarization filter 21 (Analyzer) extinguishes / absorbs while light whose polarization direction has been rotated in a liquid crystal cell through the second polarizing filter 21 passes through.

With an arrangement of the polarization filter 19th , 21 with polarization directions lying parallel to one another, only light is transmitted whose polarization direction has not been rotated in the cells. This results in a lower contrast, but at the same time a higher light yield.

The projection lens 20th has a converging lens, in particular an aspherical converging lens. Alternatively, the projection objective is a refractive-diffractive hybrid lens. In a preferred alternative, the projection objective is a Steinheil periscope lens. Such a periscope lens is a wide-angle lens made up of two meniscus lenses 20.1 , 20.2 which are arranged with their concave sides to each other. The meniscus lenses 20.1 , 20.2 aspherical meniscus lenses are preferred 20.1 , 20.2 . In a preferred embodiment, there are all or individual lenses 20.1 , 20.2 of the projection lens 20th made of plastic, for example made of PMMA, PC, PEI, COC or COP. It is also preferred that the lenses of the projection objective 20th are remunerated.

The function of the projection lens 20th is the image of the liquid crystal display 18th into the lighting area of the motor vehicle comfort projection device 10 , for example in a vehicle interior.

2 shows a perspective view of a conical light guide 14th a light source 12th , which consists of several light emitting diodes. The light emitting diodes of the light source 12th are directly on a light entry surface of the conical light guide 14th arranged, but do not touch it. The light-emitting diodes are in particular arranged in such a way that light emanating from them via the light entry surface s conical light guide 14th into the conical light guide 14th entry. The light emitting diodes are from a circuit board 22nd held mechanically and electrically contacted. The circuit board 22nd is on a heat sink 24 attached, which is set up to absorb heat released during operation of the light-emitting diodes.

3 shows details Z1 , Z2 from the 2 in the form of alternative arrangements of light emitting diodes 12.i . The light source 12th consists of several light emitting diodes 12.1 which are arranged closely packed next to one another and which are set up to emit colored light, the light color being different from light-emitting diode to light-emitting diode. The light emitting diodes can be controlled independently of one another or separated by color.

3 shows in particular different configurations of an arrangement of differently colored light-emitting diodes 12.i , e.g. as a 2x2 array, as in detail Z1 , with i = 1 to 4, or as a 2-3-2 arrangement, as in detail Z2 , with i = i to 7.

4th shows an arrangement of three light-emitting diodes 12.1 until 12.3 with which light of a first light color, such as white light, can be emitted, and a light-emitting diode 12.4 , with which light of a second light color, for example yellow light, can be emitted. The light emitting diodes 12.1 until 12.4 are arranged in such a way that the sum of the LEDs results in a square.

5 shows a plan view of an arrangement of two yellow light-emitting light-emitting diodes 12.1 , 12.2 and two white light emitting light emitting diodes 12.3 , 12.4 which together form a square and in which the light-emitting diodes emitting light of the same color are each arranged along a diagonal of the square.

6th shows a plan view of an arrangement of six light-emitting diodes 12.1 until 12.6 , which are arranged in a 3x2 matrix and each of which has a red light (light-emitting diode 12.1 ), a green light (light-emitting diode 12.2 ), a blue light (light-emitting diode 12.3 ), a purple light (light-emitting diode 12.4 ), a white light (light-emitting diode 12.5 ) and a yellow light (light emitting diode 12.6 ) can emit.

7th shows a combination of seven light-emitting diodes 12.1 until 12.7 , of which six around a central seventh light-emitting diode 12.7 are arranged around. Two of the light emitting diodes (light emitting diodes 12.1 , 12.2 ) are set up to emit white light. The other LEDs 12.3 until 12.6 are set up to emit light of a single color, the color of the light-emitting diode being different from the light-emitting diode. A light emitting diode 12.3 is set up to emit blue light. Another light emitting diode 12.4 is set up to emit yellow light. Another light emitting diode 12.5 is set up to emit cyan-colored light. Another light emitting diode 12.6 is finally set up to emit cyan-colored light.

Blue light-emitting LED chips are preferably used to generate the different colors, the light of which is converted into the respective colors by appropriate phosphor layers. By using light-emitting diodes in the basic colors red, green and blue (and If necessary, additional additional colors), not only can the color location of the light mixed from it vary within wide limits, but lighting with a large spectral bandwidth and very good color rendering values is also obtained, which is particularly important for sophisticated interior lighting in motor vehicles.

In addition, the motor vehicle comfort projection device according to the invention enables the generation of rapid sequences of individual images in the primary colors, which can then be perceived by the viewer as colored moving images. So color videos can be projected.

8th shows a plan view of the light exit surface 14.1 a conical light guide 14th of length L with a rectangular cross-section (side lengths B, H). The light entry surface has the side lengths b <B and h <H.

9 shows a section through the conical light guide 14th from the 8th that is perpendicular to a first plane of symmetry 14.2 of the light guide rod. 10 shows a section through the conical light guide from FIG 8th that is perpendicular to a second plane of symmetry 14.3 of the conical light guide 14th lies.

11 FIG. 13 shows a perspective view of the light guide rod from FIG 8th until 10 .

The ratios of sides B and H of the light exit surface 14.1 to the sides b and h of the light entry surface 14.4 are made as whole numbers as possible and are preferably in the range from 2 to 8 inclusive. The length L of the conical light guide 14th should be 2 up to and including 8 times the diagonal D of the light emitting surface 14.1 be.

Taken together, they show 8th until 11 a rod-shaped conical light guide 14th with a light entry surface 14.4 and a light exit surface 14.1 , where the light entry surface 14.4 from the light emitting surface 14.1 is separated by a lateral surface, which is made up of four side surfaces 14.5 composed. The light entry surface 14.4 and the light exit surface 14.1 are parallel to each other. The conical light guide 14th is a truncated pyramid, its transverse to the main direction of light propagation in the conical light guide 14th lying cross-sections are all rectangular or square. The conical light guide 14th consists preferably of glass, in particular of an inorganic crown glass.

The mutually corresponding side lengths of the light entry surface and light exit surface are preferably integral multiples, in particular 2 to 8 times, so that one side length of the light exit surface is, for example, 4 times as long as one side length of the light entry surface parallel to this side length. The more conical light guide preferably has two planes of symmetry 14.2 , 14.3 which contain the optical axis and which are each perpendicular to two side surfaces and the light entry surface and the light exit surface. The light entry surface 14.4 and the light exit surface 14.1 of the conical light guide are preferably coated with an anti-reflective coating.

The conical light guide 14th serves as a light mixer and as a concentrator. The light of the light source emitting light of different colors 12th is in the conical light guide 14th , whose cross-section lying transversely to the main direction of light propagation with increasing distance from the light entry surface 14.4 grows, mixed by total internal reflections. At the same time, the opening angle of the light is reduced as a result of reflections on the side surfaces of the conical light guide.

12th shows an embodiment of a motor vehicle comfort projection device 10 that differs from the automobile comfort projection device 10 the 1 through an additional deflecting mirror 26th differs. The deflecting mirror is here in the beam path between the liquid crystal display 18th and the projection lens 20th , or between the second polarization filter 21 and the projection lens 20th and bends the beam path by a bend angle. The kink angle is preferably 70 ° to 110 °, in particular 90 °.

13th shows an embodiment of a motor vehicle comfort projection device 10 that differs from the automotive comfort projection device of the 12th by a different arrangement of the deflecting mirror 26th differs. In contrast to the subject of 12th is the deflection mirror 26th in the beam path downstream of the projection lens 20th and bends the beam path by a bend angle. Here too, the kink angle is preferably 70 ° to 110 °, in particular 90 °.

Another embodiment is characterized in that the deflecting mirror is integrated as a reflective surface in a lens of the projection objective.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 10215893 C1 [0001]

Claims (20)

Motor vehicle comfort projection device (10), comprising a light source (12) and a projection lens, characterized in that the motor vehicle comfort projection device (10) has a conical light guide (14), a converging lens serving as a field lens (16) and a liquid crystal matrix display (18) as an imaging element and a projection lens (20) set up for imaging the liquid crystal display (18). Motor vehicle comfort projection device (10) according to Claim 1 , characterized in that the light source (12) has light-emitting diodes (12.i) with at least two different light colors. Motor vehicle comfort projection device (10) according to Claim 2 , characterized in that the light-emitting diodes (12.i) can be controlled independently of one another or separately according to color. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the cross section of the conical light guide (14) lying perpendicular to the main direction of propagation in the conical light guide (14) is rectangular or square. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the length of the conical light guide (14) in the main direction of propagation of the light is 2 to 8 times the diagonal (D) of the light exit surface (14.1) of the conical light guide ( 14) is. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that mutually corresponding side lengths of the light entry surface (14.4) and light exit surface (14.1) of the conical light guide (14) differ by an integral factor, the factor being the values 2 to 8 and the light exit side is longer than the light entry side that corresponds to it. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the conical light guide (14) has two planes of symmetry (14.2, 14.3) which contain the optical axis and which are each perpendicular to two side surfaces and to the light entry surface (14.4) and to the light exit surface (14.1) of the conical light guide (14). Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the field lens (16) upstream of the liquid crystal display (18) between the conical light guide (14) and the liquid crystal display (18) or between the conical light guide (14) and a first polarizer (19) is arranged. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the field lens (16) is arranged downstream of the liquid crystal display between the liquid crystal display and the projection lens (20) or between a second polarizer and the projection lens (20). Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the field lens (16) is a Fresnel lens (16.1) and that Fresnel zones of the Fresnel lens (16.1) point in the direction of the incident light. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that a focal length of the field lens (16) is greater than or equal to the focal length of the projection lens (20). Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the liquid crystal display (18) has a matrix of liquid crystal cells which rotate the direction of polarization of the transmitted light in each liquid crystal cell depending on the voltage, and that in each case a polarization filter (19) upwards of the light flow (polarizer ) and a polarization filter (21) is arranged downstream of the light flow from the liquid crystal display (18), the polarization filters (19, 21) being rotated by 90 ° with respect to one another so that light whose polarization direction in the liquid crystal display (18) has not been rotated in the following Polarization filter (21) (analyzer) is absorbed. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that linear polarization filters (19, 21) aligned in parallel are arranged on both sides of the liquid crystal display (18) so that only light is transmitted whose polarization direction is not in the liquid crystal display (18) was filmed. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the polarization filter (19) arranged upstream of the liquid crystal display (18) is a brightness enhancement film. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the polarization filters (19, 21) are combinations of reflective and absorbent polarization filters arranged one behind the other in the direction of the light flow. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the projection objective (20) has a converging lens, in particular an aspherical converging lens. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the projection lens (20) is a refractive-diffractive hybrid lens. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that the projection lens (20) is a Steinheil periscope lens, i.e. a wide-angle lens made up of two meniscus lenses (20.1, 20.2) which are arranged with their concave sides to one another, the meniscus lenses (20.1, 20.2) are in particular aspherical meniscus lenses (20.1, 20.2). Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that a deflecting mirror (26) folding the beam path is arranged between the liquid crystal display (18) and the projection lens (20) which kinks the beam path. Motor vehicle comfort projection device (10) according to one of the preceding claims, characterized in that a deflecting mirror folding the beam path is integrated as a reflecting surface in a lens of the projection objective.

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