DE102006019731A1 - Head-up-display e.g. liquid crystal display, for use in vehicle, has light source with light emitting diode, and conversion device designed so that green light, which is emitted from diode is partially converted into red light - Google Patents

Abstract

The display has a light source (LQ), which includes a light emitting diode (LED), which emits green light. A conversion device (K) is designed such that the green light, which is emitted from the light emitting diode is partially converted into red light. The conversion device is aligned to an image formation device and the light emitting diode such that the conversion of the green light into red light is implemented.

Description

The The invention relates to a head-up display, in particular a head-up display for vehicles, and a vehicle with a corresponding head-up display.

It is a variety of different in particular in the vehicle sector Types of display devices known. To stand in the foreground of development efforts currently known as head-up displays.

Such head-up displays are for example from the DE 10344686 A1 and the EP 1143288 A1 known. In this case, light from a light source, for example a light-emitting diode, is directed by light-directing optics onto an image-generating device, such as a liquid-crystal display, and the image thus generated is projected onto the windshield of a vehicle.

Problematic it is that for the realization of the head-up display in the vehicle only little space available stands. In addition, the light utilization of known head-up displays is very low is, and typically less than 5% of the generated light for the driver In addition, the energy efficiency of known head-up displays is visible very low, and the readability of the projected image with respect to Brightness can be improved. In addition, a lot of waste heat generated, which are dissipated with a high design cost got to.

From the DE 10 2004 016 232 A1 For generating white light, it is known to combine UV or blue light emitting diodes (LEDs) with luminescent materials (eg phosphors) which convert the light emitted by the LEDs into light of a longer wavelength. In such devices, the UV or blue light emission of the LED activates (stimulates) a phosphor composition. In turn, the excited phosphor composition emits light of a longer wavelength. The net result is a light-emitting device that emits light having a plurality of wavelengths in the visible spectrum. A corresponding combination of different wavelengths in the visible spectrum can be perceived by the human eye as white light. The composition of the phosphor changes the color balance and other characteristics of the emitted light. Currently, such white LEDs are used in head-up displays. However, the color range actually required in preferred head-up displays does not include white and blue.

Instead an intense red is needed that again with white LEDs is difficult to realize.

Of the The invention is based on the object of specifying a technical teaching, with a head-up display, especially in a vehicle environment, can be operated efficiently.

These The object is solved by the features of the independent claims. advantageous Further developments of the invention are the dependent claims remove.

The The invention is thus initially based on the realization that green Light-emitting diodes due to mass production meanwhile particularly can be produced economically.

Further the invention is based on the finding that from the combination of red and green light all essential for a vehicle display generates colors required in a head-up display can be.

Under consideration and linking this Findings are now proposed, green light-emitting diodes in combination use with red phosphorus in a head-up display, and by means of the green Light-emitting diodes thereby green and to generate red light that green emitted from the light-emitting diodes Light to such a big one Part, in particular more than 40%, converted to red light is that the resulting spectrum is preferably the color range between green over yellow and orange to red very well balanced, so with relatively homogeneous Intensity distribution, covers.

Thereby is achieved that the light source of a head-up display are produced inexpensively can, and that generated by the LEDs light efficiently, namely in Wavelength ranges, for displaying information, in particular in a vehicle, are particularly important, used becomes. The waste heat and therefore the energy consumption will be greatly reduced by the a head-up display projected information will be easier to read and / or the number of required light-emitting diodes can be reduced become.

to Image formation is preferably an LC (Liquid Crystal) display or a LCOS (Liquid Crystal on Silicon) display.

The green light preferably comprises light having a wavelength between 520 and 565 nm.

The Red light preferably comprises light having a wavelength greater than 610 nm.

In the context of the invention, however, light of a particular color is interpreted broadly, so that at For example, green light is to be understood as light having a wavelength of 520, 530, 540, 550 and / or 560 nm.

Especially Preferably, the conversion device is configured in such a way that that they are for green light partially, in particular more than 30%, 40% or 50% and / or to less than 50%, 60 or 70% is permeable. Because these shares of the green Light emitting diode generated light, in particular directly or after suitable filtering or mixing, for the display of information used in a vehicle particularly advantageous.

To An advantageous embodiment of the invention is the conversion device between the light source and the imaging device, in particular a switchable light filter or a display arranged.

Especially Preferably, the conversion device between the light source and arranged downstream of the light source optical steering system. One such a head-up display proved to be in the manufacture and integration into a vehicle especially easy. It is also a sensitive conversion device then from dirt and touch through a user or driver protected.

Preferably The conversion device comprises a phosphorus substance, which Stimulation by green Light emits red light. For example, it is the phosphorus substance around red phosphorus.

Especially Preferably, the conversion device is in particular uniformly thick Layer in the emission direction of the LED on a transparent Support material in particular a light-emitting diode housing or a lens, applied or integrated in it. This configuration is especially functional and. inexpensive. Alternatively, the conversion device covers the LED, ie the light-active semiconductor material, direct or is merely separated therefrom by a separating layer.

Preferably The image generation device comprises a plurality of pixels, each one to the transmission of green and / or red light can be controlled. Especially when used a matrix image generator, such as a TFT (Thin Film Transistor) display, the pixels include filters, which to the transmission of green and / or red light can be controlled. A filter that transmits is controlled by blue light is preferably not provided.

Especially when using conventional, in big numbers for example Mobile phones and digital cameras manufactured, imaging devices is preferably the filter which is normally for transmission is controlled by blue light, through another filter, which to the transmission of green and / or red light can be controlled replaced.

Especially preferred is the installation of one of the above head-up displays in a vehicle, wherein the generated by the image generating device Image is projected on a windshield of the vehicle. Because by the teaching of the invention can just the colors are projected onto a windshield that are particularly important for displaying information on the road.

in the The invention will now be described by way of example with reference to FIG closer to the following figures explains:

1 shows a simplified schematic representation of a head-up display, wherein the conversion device is mounted on the light-guiding optics;

2 shows a simplified schematic representation of a head-up display, wherein the conversion device is mounted in the vicinity of the LEDs.

1 shows a head-up display HUD of a vehicle with a light source LQ, which is based on green LEDs LED. The light emitted by the LEDs LED contains substantially green light. The light emitted by the LEDs LED light is indirectly or directly, optionally after filtering, directed to a conversion layer K, which is selected or configured and arranged such that the light emitted by the LEDs LED green light with respect to the intensity depending on the embodiment at least 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% is converted into red light, that is converted into light of longer wavelength.

The Conversion and thus the design of a suitable conversion layer can for example, based on a luminescence conversion and are in itself within the framework of expert action, why not closer at this point will be discussed.

moreover For example, the conversion layer K is selected and arranged to be for the green light emitted from the LED lights, depending on the intensity embodiment at least 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% is permeable.

The light emerging from the conversion layer K is then passed through a suitable light-guiding optics LLO on an image forming device D, which includes, for example, an LCD. The individually controllable Pixels of the image generation device D each comprise at least two, in particular, three individually controllable subpixels. Each of these subpixels is provided with a color filter, with two subpixels for red Light permeable can be switched and a subpixel for green light permeable can be switched or vice versa.

ever after driving the pixels, in particular the subpixel occurs resolved after pixels red, green or red-green mixed light from the image forming device D, which, optionally after further filtering, finally, for example on the windshield, not shown, of a vehicle, projected becomes.

The shown head-up display can in addition to the explained components more for a head-up display typical components, such as different filters, an imaging optics, a housing, a Control device, etc., on which only the simplicity not closer was received.

alternative to the illustrated arrangement of the conversion layer K on the light steering optics LLO, the Conversion layer also on one or more transparent support plates arranged or integrated therein, between the light source and Imaging device in the beam path of the LEDs are, and the component of a housing the light source or the LEDs can be.

2 also shows a head-up display HUD of a vehicle with a light source LQ, which is based on green LEDs LED. The components correspond in function and designation to the components 1 , The main difference between the head-up displays HUD shown in the two figures is that in 2 the conversion device K is not covered as a unit, the light-guiding optics LLO, but instead is implemented distributed and each covers the transparent housing or the transparent capsule of the LEDs LED. Alternatively, it is also possible for the conversion device to directly surround or cover the light-emitting diode, for example the corresponding semiconductor material.

Claims (10)

Head-up display (HUD) with a light source (LQ) comprising at least one light emitting diode (LED) emitting green light, With an image forming device (D) and with a conversion device (K), which is configured such that green emitted from the light emitting diode Light is partially converted to red light. Head-up display (HUD) according to claim 1, in which the image generating means (D) for generating pixels the following colors is set up: - green, - red or - Color mixtures from green and red. Head-up display (HUD) after one of the previous ones Claims, in which the conversion device to the image forming device (D) and the light-emitting diodes adapted by them for conversion from green Light in red light is. Head-up display (HUD) after one of the previous ones claims with a conversion device (K), which is designed in such a way that they are for the go-ahead at least partially permeable is. Head-up display (HUD) after one of the previous ones claims with a light-guiding optic (LLO) arranged downstream of the light source (LQ), wherein the conversion device (K) between the light source (LQ) and the light source (LQ) downstream light-steering optics (LLO) is arranged. Head-up display (HUD) after one of the previous ones Claims, in which the conversion device (K) is designed flat and one of the light source following element, in particular the light-steering optics (LLO), at least partially covered. Head-up display (HUD) after one of the previous ones Claims, in which the conversion device (K) is a transparent element a light emitting diode in the emission direction of the LED surface covered. Head-up display (HUD) after one of the previous ones Claims, wherein the image forming device (D) comprises a plurality of pixels, the each to the transmission of green and / or red light can be controlled. Head-up display (HUD) after one of the previous ones Claims, with a transparent element downstream of the light source (LQ), in which the conversion device (K) directly on this transparent Element is up or introduced. Vehicle with a head-up display (HUD) after one of the preceding claims, wherein the image generated by the image forming device (D) is projected to a windshield of the vehicle or to an additionally inserted between the windshield and driver's eye reflection disc.