HEADLIGHT SYSTEM FOR VEHICLES

Abstract

A headlamp system is provided for vehicles with an imaging unit and with an optical unit. The optical unit generates a light distribution that features a plurality of light patches. The light patches are each generated by mapping of at least one light pixel of the imaging unit. An actuator unit includes a corrective mechanism, by which, in event of presence of a defective light pixel that cannot be mapped by the optical unit on a light patch, at least one corrective light pixel is actuated, by means of which a light patch adjacent to the defective light patch not illuminated by the defective light pixel features a changed intensity progression in comparison to non-defective state. At least one flight patch adjacent to the defective light patch features an increased corrective intensity progression in comparison to the non-defective state.

Claims

1. A headlamp system for vehicles, the headlamp system comprising: an imaging unit; an optical unit for generating a light distribution (L) that features a plurality of illuminated light patches, where the light patches are generated by mapping at least one light pixel of the imaging unit, an actuator unit for actuating the imaging unit, where the actuator unit includes a corrective mechanism by which a presence of a defective light pixel, that cannot be mapped by the optical unit on a light patch, at least one corrective light pixel is actuated by which light patches adjacent to the defective light patch not illuminated by the defective light pixel feature a changed corrective intensity progression in comparison to a non-defective state; wherein the optical unit is designed such that the intensity of the respective light patches is formed by the overlapping of a first light portion that is generated by the light pixel the light of which is mapped by the optical unit onto the light patch, and a second light portion, that is generated by at least one light pixel the light of which is mapped by the optical unit onto an adjacent light patch, and the corrective mechanism is designed such that at least one light patch adjacent to the defective light patch features a corrective intensity progression that is increased in comparison to the non-defective state.

2. The headlamp system in accordance with claim 1, wherein the light patches are arranged in rows and columns to form an illumination area.

3. The headlamp system in accordance with claim 1, wherein the imaging unit and/or the optical unit are designed such that the maximum level of the intensity progression is arranged in a central area of the light patch.

4. The headlamp system in accordance with claim 1, wherein the optical unit is designed such that each light pixel is mapped in an excessive radiance section extending beyond the light patch, where the excessive radiance section covers adjacent light patches and where the intensity in the overexposure section is lower than the intensity within the light patch.

5. The headlamp system in accordance with claim 1, wherein the excessive radiance section of the light pixel features an extent (dS) that is smaller than the fourfold extent (dF) of the light patches.

6. The headlamp system in accordance with claim 1, wherein the light patches are mapped at the same size on a measuring screen.

7. The headlamp system in accordance with claim 1, wherein the corrective light pixel is arranged adjacent to the defective light pixel.

8. The headlamp system in accordance with claim 1, wherein the optical unit is designed such that the intensity progression of the mapped light pixel runs in one direction after the fashion of a bell curve, where the maximum intensity is arranged in the central area of the respective light patch.

9. The headlamp system in accordance with claim 1, wherein the corrective mechanism are designed such that several corrective light pixels arranged around the defective light pixel are actuated in a corrective state.

10. The headlamp system in accordance with claim 1, wherein a defect identification unit is provided, by which the presence of defective light pixels can be determined.

11. The headlamp system in accordance with claim 10, wherein the error detection unit features a light sensor that detects the light distribution (L) mapped on a measuring screen and the defect identification unit features an evaluation unit that evaluates the image data provided by the light sensor and, on the basis of an allocation regulation, determines from the location of the defective light patch of light distribution (L) to the location of the defective light pixel in the imaging unit.

12. The headlamp system in accordance with claim 10, wherein the defect identification unit features a defect measuring routineby which the light pixels are subjected to a measuring current and/or a measuring voltage, such that an error signal can be generated from the measured values that defines the defectiveness of each light pixel checked.

13. The headlamp system in accordance with claim 1, wherein the imaging unit features a plurality of individually actuatable light sources arranged in the form of a matrix, features firstly or secondly a light source unit and a liquid crystal device (LCD, LCoS) or thirdly a light source unit and a micromirror device (DMD).

14. A method for compensating for defective light pixels of a headlamp for vehicles, the method comprising the steps of: mapping each light pixel by an optical unit to light patches of a light distribution (L) that, through overlapping, form an illumination field of a light distribution (L) such that other light pixels are actuated in such a way that any contrast between a defective light patch and the same adjacent light patch is reduced actuating the light pixels in such a way that the illuminance of the light patch adjacent to the defective light patch is greater that light patches further way from the defective light patch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Reference is now made more particularly to the drawings, which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views.

[0019] FIG. 1 illustrates a block diagram of an inventive headlamp system.

[0020] FIG. 2 illustrates a top view of a light pixel field.

[0021] FIG. 3 illustrates a top view of an illumination area of a light distribution.

[0022] FIG. 4 illustrates an intensity distribution of light patches along a side section IV-IV in FIG. 3.

[0023] FIG. 5 illustrates an intensity distribution of light patches along a side section V-V in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

[0024] A headlamp system for vehicles essentially consists of an imaging unit 1 that features a plurality of light pixels P.sub.11, P.sub.12... P.sub.nm preferentially arranged in the form of a matrix that are arranged in rows Z1 through Zn and columns S1 through Sm. Furthermore, the headlamp system comprises an optical unit 2 consisting, for example, of a number of lens elements by means of which the light emitted by the light pixels P.sub.11, P.sub.12... P.sub.nm is mapped to a light distribution L in a vehicle environment. In the present sample embodiment, the light distribution L is designed as a low-beam light distribution. Furthermore, the headlamp system comprises an actuator unit 3 by means of which the imaging unit 1 can be actuated.

[0025] The imaging unit 1 can, for example, feature a large number of light sources arranged in the form of a matrix that can be individually actuated, for example LED light sources. By means of the actuator unit 3, the light sources can be switched on or off, or be dimmed, such that a specified light distribution is generated, for example city light, highway light or the like. In particular, it is possible to generate a glare-free high beam where the traffic objects recognized in the vehicle environment can be excluded in the high-beam distribution depending on their presence.

[0026] In accordance with an alternative embodiment of the invention, the imaging unit 1 can feature a liquid crystal unit as an LCD display or as an LCoS (liquid crystal on silicon) unit and a light source unit. In this respect, the liquid crystal elements arranged in the form of a matrix or pixelwise serve as shutter elements that either let light from the light source through or block it. In this respect, the liquid crystal elements serve as light pixels as defined by the invention. As an alternative, the imaging unit 1 can feature a light source unit and a micromirror device (DMD), where the individual micromirror elements of the microelements are arranged in the form of a matrix or pixelwise in the range of several million so as to be pivotable. The micromirror elements have at least one On state, in which the light from the light source unit is directed onto the optical unit and at least one Off state in which the light emitted by the light source is absorbed.

[0027] The design of the imaging unit creates a high resolution headlamp or a high resolution headlamp system.

[0028] To generate the light distribution, one part or all light pixels P.sub.11, P.sub.12... P.sub.nm of the light pixel field are actuated such that the specified light distribution L is generated. If the light pixels P.sub.11, P.sub.12... P.sub.nm are in a switched-on state, these are mapped by means of the optical unit 2 to light patches A.sub.11, A.sub.12...A.sub.nm of an illumination area 5 shown in FIG. 3. The illumination area 5 comprises a plurality of light patches A.sub.11, A.sub.12...A.sub.nm arranged in the form of a matrix. Each light patch A.sub.11, A.sub.12...A.sub.nm is allocated to a light pixel P.sub.11, P.sub.12... P.sub.nm. Thus, for example, in switched-on state, the light pixel P.sub.22 is mapped by means of the optical unit 2 to the light patch A.sub.22. The light pixel P.sub.23 is mapped to the light patch A.sub.23, etc.

[0029] FIG. 1 shows a section of a light pixel field with a plurality of light pixels P.sub.11, P.sub.12... P.sub.nm arranged in the form of a matrix. Let it be assumed that the pixel P.sub.35 which is located in the third row and the fifth column is defective, i.e. cannot be caused to light up by the corresponding actuation.

[0030] The optical unit 2 is designed in such a way that the light pixels P.sub.11, P.sub.12... P.sub.nm are not mapped according to a right angle function on the illumination area 5 but forming a bell curve 6 forming a maximum intensity I.sub.0 that runs continuously along the path. The optical unit 2 leads to a local widening and/or diffusion of the light pixel imaging. As can be seen from FIG. 3, each light pixel P.sub.11, P.sub.12... P.sub.nm is mapped in such a way that a core section 7 covering a light patch A.sub.11, A.sub.12...A.sub.nm is formed with increased intensity and an excessive radiance 8 section covering adjacent light patches A.sub.11, A.sub.12... A.sub.nm with lower intensity. The light pixel P.sub.22 is thus mapped in such a way that the core section 7 (central section) of the light pixel P.sub.22 hits light patch A.sub.22, whereas the excessive radiance section 8 covers the light patches A.sub.21 and A.sub.23 adjacent in the row and light patches A.sub.12 and A.sub.32 adjacent in the column. The light patches A.sub.11, A.sub.13, A.sub.31, A.sub.33 are only partially covered or illuminated. The excessive radiance section 8 thus extends in the form of a ring around core section 7. An extent ds of a light section 9 formed by the core section 7 and the excessive radiance section 8 is smaller than the fourfold extent d.sub.F of the light patches A.sub.11, A.sub.12...A.sub.nm. In the present sample embodiment, the extent ds of light section 9 corresponds roughly to three times the extent d.sub.F of light patches A.sub.11, A.sub.12...A.sub.nm.

[0031] Let it be assumed in the present sample embodiment that light patches A.sub.11, A.sub.12...A.sub.nm appear as a square or a circle on a measuring screen and are of equal sizes.

[0032] It can be seen from FIG. 3 that when light pixels P.sub.11, P.sub.12... P.sub.nm are working correction the same maximum intensity I.sub.0 is generated in each of the core sections 7. Adjacent light patches A.sub.11, A.sub.12...A.sub.nm in switched-on state of the corresponding light pixels P.sub.11, P.sub.12... P.sub.nm thus feature an equally strong illuminance or intensity.

[0033] The headlamp system further features a defect identification unit 10 by means of which the presence of defective or faulty light pixels P.sub.11, P.sub.12... P.sub.nm can be detected. The defective light pixels referred to in the following are defective light pixels P.sub.11, P.sub.12... P.sub.nm. As an alternative, the distribution of the defective light pixels can also be provided by the manufacturer of the imaging unit 1, such that the defect identification unit 10 can be dispensed with.

[0034] In accordance with a first embodiment, the defect identification unit 10 can feature a light sensor 11, by means of which light patches A.sub.11, A.sub.12...A.sub.nm appearing dark on a measuring screen can be identified as defective light patches. The light sensor 11 can, for example, take the form of a camera. The sensor signal provided by light sensor 11 is directed to an evaluation device 12 of the defect identification unit 10 in which the image data detected by light sensor 11 can be evaluated and determined by means of an allocation regulation from the location of the defective illuminated area of the light distribution L to the location of the defective light pixel (P.sub.35) in the imaging unit 1.

[0035] In accordance with an alternative embodiment of the defect identification device 10, the defect identification evaluation of imaging unit 1 is performed. For this purpose, the defect measuring routine 10 features a defect measuring routine 13 that checks the light pixels P.sub.11, P.sub.12... P.sub.nm for proper functioning. For example, light pixels P.sub.11, P.sub.12... P.sub.nm can be actuated with a measuring voltage or a measuring current, preferentially rated current or rated voltage, in order to establish whether electrical values of the light pixel P.sub.11, P.sub.12... P.sub.nm do not exceed a specified working range. If an electrical value, such as amperage, is outside of this range, it may be concluded that this light pixel is defective.

[0036] If a defective light pixel has been detected by means of the defect identification unit 10, for example light pixel P.sub.35, the actuator unit 3 provides for corrective mechanism for compensating for or correcting the illumination for light patch A.sub.35. In the present sample embodiment, four light pixels P.sub.34, P.sub.36, P.sub.25, P.sub.45 adjacent to the defective light pixel P.sub.35 are actuated in such a way that light patches A.sub.34, A.sub.36, A.sub.25, A.sub.45 adjacent to the defective light patch A.sub.35 are illuminated with an increased maximum corrective intensity value I.sub.1 in comparison to the maximum intensity I.sub.0. The maximum corrective intensity value I.sub.1 is larger than the maximum intensity value I.sub.0 of the light patches A.sub.23, A.sub.24, A.sub.26, A.sub.27, A.sub.33, A.sub.44, A.sub.46, A.sub.47 comparatively further away from the defective light patch A.sub.35 or the light patches whose adjacent light patch is not allocated a defective light pixel.

[0037] FIG. 4 shows the intensity distributions I.sub.21, I.sub.22, I.sub.23 of light patches A.sub.21, A.sub.22, A.sub.23, to which non-defective light pixels P.sub.21, P.sub.22, P.sub.23 are allocated or on which non-defective light pixels P.sub.21, P.sub.22, P.sub.23 are mapped. The intensity distributions I.sub.21, I.sub.22, I.sub.23 are identical in form, where, due to the excessive radiance of the mapped light onto adjacent light patches, each of the light patches features a first light portion 14 that is generated by the mapping of the same allocated light pixel, and a second light portion 15, that is generated by the light patches shining into the adjacent light patches. In the present sample embodiment, the illumination of the light patch A.sub.22 comprises the first light portion 14 hatched in one direction under the intensity curve I.sub.22 and the second light portion 15 arranged hatched in the opposite direction, that results from the adjacent intensity curves I.sub.21 and I.sub.23. The overlapping or excessive radiance of the mapped light patches onto adjacent light patches is exploited by the invention in this respect, as described in the following.

[0038] FIG. 5 shows three intensity progressions I.sub.I, I.sub.II, I.sub.III of the adjacent light patches A.sub.24, A.sub.35, A.sub.36 in the event of the presence of the defective light patch A.sub.35. The intensity progression I.sub.I shows the idealized case in which no excessive radiance of adjacent light patches by the light pixels takes place. In this case, the intensity in the defective light pixel field A.sub.35 would be zero, whereas the intensity in the adjacent correct light patches is I.sub.0. The dotted intensity progression I.sub.II corresponds to an actuation of the light pixels P.sub.34, P.sub.36 in the non-defective state of the light pixel P.sub.35, i.e. if light pixel P.sub.35 were not defective. A third intensity progression I.sub.III corresponds to the intensity of the light pixels A.sub.34 and A.sub.36 in the corrective state (defective case of light pixel P.sub.35), i.e. light pixel P.sub.35 being faulty. In this respect. the light patches A.sub.25, A.sub.34, A.sub.36, A.sub.45 adjacent to the defective light patch A.sub.35 an increased intensity progression I.sub.III with the maximum corrective intensity value I.sub.1. As the corrective light pixels P.sub.25, P.sub.34, P.sub.36, P.sub.45 are responsible for illumination of the adjacent light patches A.sub.25, A.sub.34, A.sub.36, A.sub.45 with their excessive radiance sections 8 also illuminate the defective light patch A.sub.35, an increase in the intensity progression or the illuminance progression takes place in the defective light patch A.sub.35. In comparison to a non-defective state of the light pixel P.sub.35, a fourfold increase in intensity or illuminance takes place, where, in the defective light patch A.sub.35 a minimum intensity I.sub.K is generated, which is significantly larger than a minimum intensity I.sub.F without correction. The minimum intensity I.sub.K of the defective light patch A.sub.35 is greater than the minimum intensity I.sub.F in the case of non-correction. Furthermore, the excessive radiance in the adjacent light patch is smaller than the increase in the intensity in the defective light patch A.sub.35. Therefore, in addition to the increase in illuminance in the defective light patch A.sub.35, this gives rise to a reduction in the contrast between the defective light patch A.sub.35 and the adjacent light patches A.sub.25, A.sub.34, A.sub.36, A.sub.45, on the one hand, and a larger reduction in the contrast to the light patches A.sub.31, A.sub.32, A.sub.33.... arranged further away in comparison to the adjacent light patches A.sub.25, A.sub.34, A.sub.36, A.sub.45.

[00001]${\text{I}}_{\text{1}}-{\text{I}}_{\text{K}}\text{<}{\text{I}}_{\text{0}}-{\text{I}}_{\text{F}},$

where I.sub.1 is the maximum corrective intensity of the adjacent light patches A.sub.25, A.sub.34, A.sub.36, A.sub.45, I.sub.K the minimum corrective intensity in the defective light patch A.sub.35 with correction, I.sub.F minimum intensity in the defective light patch A.sub.35 without correction, I.sub.0 maximum intensity of the non-defective light patch A.sub.22, A.sub.23, A.sub.24..., that connect to the adjacent light patches A.sub.23, A.sub.34, A.sub.36, A.sub.45,

[0039] Furthermore, the following applies:

[00002]${\text{I}}_{\text{0}}-{\text{I}}_{\text{K}}=\text{Δ}{\text{Ι}}_{\text{A}}<{\text{S}}_{\text{A}}$

[0040] The difference ΔI.sub.A, is smaller than a specified threshold value S.sub.A. The threshold value S.sub.A defines the minimum illuminance in the defective light patch A.sub.35, so that the light patch A.sub.35 is not perceived as a black hole.

[0041] Furthermore, the following applies:

[00003]${\text{I}}_{\text{1}}-{\text{I}}_0=\text{Δ}{\text{I}}_{\text{B}}<{\text{S}}_{\text{B}}$

[0042] The excessive intensity level ΔI.sub.B that represents the difference between I.sub.1 and I.sub.0, is smaller than a threshold value S.sub.B. The threshold value S.sub.B states a maximum increase excessive radiance such that the excessively illuminated adjacent light patches A.sub.25, A.sub.34, A.sub.36, A.sub.45 do not lead to an undesired bright ring or rim around the defective light patch A.sub.35. The threshold value S.sub.B thus limits the intensity difference to the light patches that are arranged on a different side to the defective light patch A.sub.35.

[0043] After detecting the location of the defective light pixel A.sub.35, the corrective light pixels P.sub.25, P.sub.34, P.sub.36, P.sub.45, that are preferentially arranged adjacent to the defective light pixel P.sub.35 are actuated by the actuator unit 3 at a higher power such that the excessive brightness shown in FIG. 5 occurs with the light patches adjacent to the defective light patch A.sub.35, which is accompanied at the same time by an increase in the brightness in the defective light patch A.sub.35.

TABLE-US-00001 List of reference numbers 1 Imaging unit 2 Optical unit 3 Actuator unit 5 Illumination area 6 Bell curve 7 Core section 8 Excessive radiance section 9 Light section 10 Defect identification unit 11 Light sensor 12 Evaluation device 13 Defect measuring routine 14 1. Light portion 15 2. Light portion P.sub.11...P.sub.nm Light pixels A.sub.11...A.sub.nm Light patches L Light distribution d.sub.S,d.sub.F Extent S.sub.A,S.sub.B Threshold Δ.sub.IB Intensity increase Δ.sub.IA Difference I.sub.21,I.sub.22,I.sub.23 Intensity distributions I.sub.0 Maximum intensity I.sub.K,I.sub.F Minimum intensity I.sub.1 Corrective intensity value Z Rows S Columns