Illumination device for automobile floodlights

Abstract

To provide an improved illumination device that ensures achromatic and thermally robust properties. [Solution] An illumination device for an automobile floodlight, the illumination device includes at least one light source and a projection lens system configured to project light in a light distribution in a main radiation direction (X) forward of the illumination device, the projection lens system being composed of: a first lens (100) having a first focal point, where the first lens is aspheric and manufactured from precision glass using precision glass molding, the first lens having a convex exit surface and a concave entrance surface for increasing light input, the first lens having a refractive index of n≧1.8; a second lens (200) having a second focal point, where the second lens is manufactured from glass using glass grinding; and a third lens (300) having a third focal point. a fourth lens (400) having a fourth focal point, where the fourth lens is configured as an aspheric biconcave lens made of plastic; and an aperture (500) disposed between the third lens (300) and the fourth lens (400), wherein the second lens (200) and the third lens (300) are configured to cooperate as an achromatic lens pair to avoid chromatic aberration, and the third lens (300) and the fourth lens (400) have substantially the same coefficient of thermal expansion, and the third lens (300) and the fourth lens (400) are configured to cooperate as an athermal lens pair to avoid displacement of the common focal point at various temperatures.

Description

[Technical field]

[0001] The present invention relates to an illumination device for an automotive floodlight, the illumination device comprising at least one light source and a projection lens system configured to project light of the at least one light source in a main radiation direction forward of the illumination device in the form of a light distribution, the projection lens system having a common focal point, and the at least one light source being arranged at the common focal point.

[0002] The invention likewise relates to a vehicle floodlight comprising at least one illumination device according to the invention. [Background technology]

[0003] Projection lens systems, especially high resolution ones, should have achromatic and / or thermally robust properties. To guarantee the aforementioned properties, projection lens systems usually consist of multiple individual lenses or require materials that are very expensive and difficult to process. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 123459 [Patent Document 2] US Patent Application Publication No. 2017 / 234497 [Patent Document 3] China Patent Application Publication No. 112882211 [Patent Document 4] US Patent Application Publication No. 2013 / 128084 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, high-resolution projection optical systems for vehicles are preferably made of plastic (spherical lens / aspherical lens) due to the high cost of glass materials. In this case, the plastic materials are mainly PC (polycarbonate) and PMMA (polymethyl methacrylate). However, it is difficult to guarantee the achromatic and thermally robust properties of these plastics, because the refractive index and Abbe number are limited, and anti-reflection processing may cause problems of reducing optical efficiency.

[0006] In addition, it is difficult to guarantee the optical performance of plastic lens combinations over a wide temperature range: plastic materials are usually subject to strong temperature fluctuations, which can lead to thermal drift phenomena that change the focus of the optical system and a corresponding decrease in image quality (contrast) of the light pattern.

[0007] When an optical system is used within a large temperature range, the refractive index and spacing of the individual lenses relative to one another can change, resulting in a clear degradation of imaging performance, which, as mentioned above, typically results in the object to be imaged becoming out of focus under such thermal effects.

[0008] The achromatic and thermal dependences are often significantly stronger in plastics than in glass and, in the case of thermally induced changes, are many times stronger than the glass values, which is therefore a very important parameter since in the automotive sector temperature fluctuations from -40°C to 120°C prevail.

[0009] It is an object of the present invention to provide an improved illumination device. [Means for solving the problem]

[0010] The object is achieved by providing an irradiation device as described at the beginning, which comprises: The projection lens system consists of: - a first lens having a first focal point, the first lens being aspheric, manufactured from precision glass using precision glass molding, and disposed immediately after the at least one light source in a light path of the at least one light source in the main radiation direction, the first lens having a convex exit surface and a concave entrance surface for increasing light incidence, the first lens being configured to collimate light of the at least one light source in the main radiation direction, the first lens having a refractive index of n≧1.8; a second lens having a second focal point, the second lens being arranged immediately after the first lens in the main radiation direction and configured as a spherical biconvex focusing lens, the second lens being manufactured from glass by means of glass grinding and having an Abbe number greater than 60; - Has a third focus a third lens, the third lens being arranged immediately behind the second lens in the main radiation direction and configured as an aspheric biconcave lens made of plastic, the third lens having an Abbe number smaller than 25; - Article 4 a fourth lens having a focal point, the fourth lens being disposed immediately behind the third lens in the main radiation direction and configured as an aspheric biconvex focusing lens made of plastic; - a diaphragm arranged between the third lens and the fourth lens, the diaphragm being configured to partially block light emitted from the third lens in the direction of the fourth lens, whereby the diaphragm cooperates in forming a forward light distribution of the illumination device; the second lens and the third lens are configured to cooperate as an achromatic lens pair to avoid chromatic aberration; the third lens and the fourth lens have substantially the same coefficient of thermal expansion, and the third lens and the fourth lens are configured to cooperate as an athermal lens pair to avoid displacement of the common focal point at various temperatures; This is solved by: That is, according to the first aspect of the present invention, An illumination device for an automobile floodlight, comprising: the illumination device includes at least one light source and a projection lens system configured to project light of the at least one light source in a light distribution in a main emission direction forward of the illumination device, the projection lens system having a common focal point, the at least one light source being disposed at the common focal point; The projection lens system comprises: a first lens having a first focal point, the first lens being aspheric, made of precision glass moulded precision glass, and arranged immediately after the at least one light source in the light path of the at least one light source in the main radiation direction, the first lens having a convex exit surface and a concave entrance surface for increasing light incidence, the first lens being configured to collimate the light of the at least one light source in the main radiation direction, the first lens having a refractive index of n≧1.8, a second lens having a second focal point, the second lens being arranged immediately behind the first lens in the main radiation direction and configured as a spherical biconvex focusing lens, the second lens being made of glass that has been polished and has an Abbe number of 60 or greater; a third lens having a third focal point, said third lens being arranged immediately behind said second lens in said main radiation direction and configured as an aspheric biconcave lens made of plastic, said third lens having an Abbe number smaller than 25, a fourth lens having a fourth focal point, said fourth lens being arranged immediately behind said third lens in said main emission direction and configured as an aspheric biconvex focusing lens made of plastic, - a diaphragm arranged between the third lens and the fourth lens, the diaphragm being configured to partially block light emitted from the third lens in the direction of the fourth lens, whereby the diaphragm cooperates in forming the light distribution in front of the illumination device; the second lens and the third lens are configured to cooperate as an achromatic lens pair to avoid chromatic aberration; the third lens and the fourth lens have the same thermal expansion coefficient, and the third lens and the fourth lens are configured to cooperate as an athermal lens pair to avoid displacement of the common focal point at different temperatures; An illumination device is provided, characterized in that According to a second aspect of the present invention, There is provided a vehicle floodlight comprising at least one illumination device according to the first aspect. It should be noted that the reference numerals in the claims of the present application are intended solely to facilitate understanding of the present invention and are not intended to limit the present invention to the illustrated forms. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the present invention, the following configurations are possible. (Form 1) An illumination device for an automobile floodlight, comprising: the illumination device includes at least one light source and a projection lens system configured to project light of the at least one light source in a light distribution in a main emission direction forward of the illumination device, the projection lens system having a common focal point, the at least one light source being disposed at the common focal point; The projection lens system comprises: a first lens having a first focal point, the first lens being aspheric, manufactured from precision glass using precision glass molding, and disposed immediately after the at least one light source in a light path of the at least one light source in the main radiation direction, the first lens having a convex exit surface and a concave entrance surface for increasing light incidence, the first lens being configured to collimate light of the at least one light source in the main radiation direction, the first lens having a refractive index of n≧1.8, a second lens having a second focal point, the second lens being arranged immediately after the first lens in the main emission direction and configured as a spherical biconvex focusing lens, the second lens being manufactured from glass using glass grinding and having an Abbe number greater than 60; a third lens having a third focal point, said third lens being arranged immediately behind said second lens in said main radiation direction and configured as an aspheric biconcave lens made of plastic, said third lens having an Abbe number smaller than 25, a fourth lens having a fourth focal point, said fourth lens being arranged immediately behind said third lens in said main emission direction and configured as an aspheric biconvex focusing lens made of plastic, - a diaphragm arranged between the third lens and the fourth lens, the diaphragm being configured to partially block light emitted from the third lens in the direction of the fourth lens, whereby the diaphragm cooperates in forming the light distribution in front of the illumination device; the second lens and the third lens are configured to cooperate as an achromatic lens pair to avoid chromatic aberration; Also, the third lens and the fourth lens have substantially the same coefficient of thermal expansion, and the third lens and the fourth lens are configured to cooperate as an athermal lens pair to avoid displacement of the common focal point at different temperatures. (Form 2) It is preferable that the second lens, the third lens, and the fourth lens have a refractive index of n≦1.7. (Form 3) Preferably, the second lens has an Abbe number of 60 and the third lens has an Abbe number of 23. (Form 4) The second lens has a higher Abbe number than the third lens, preferably in a ratio of 1:2.5, especially 1:3, than the third lens. (Form 5) The diaphragm preferably has an opening through which light can pass. (Form 6) It is therefore preferable to construct a high resolution projection illumination system. (Form 7) The light distribution is preferably a low beam distribution and / or a high beam distribution. (Form 8) The at least one light source is preferably configured as a plurality of light emitting diodes, which are preferably arranged in a matrix arrangement of rows and columns. (Form 9) It is preferable that the first lens, the second lens, the third lens, and the fourth lens each have an optical axis, and the optical axes of these lenses are located on a common optical axis or coincide at a common optical axis. (Form 10) 10. An automobile floodlight comprising at least one irradiation device according to any one of the first to ninth aspects.

[0012] Because the first lens, which is closest to at least one light source, is manufactured by precision glass molding, the first lens has particularly high robustness in the sense that it experiences little change in size or characteristics at high temperatures or when the temperature fluctuates.

[0013] It is noted that the third lens also has a focal point, but this focal point is a negative focal point (minus focal point).

[0014] The common focus is one overall focus of the projection optical system obtained by combining the individual foci of the first lens, the second lens, the third lens, and the fourth lens, where the individual foci differ in their positions.

[0015] On that basis, the second lens can be produced using glass grinding, which is in principle a common method for producing glass lenses, where the second lens does not meet the same high requirements as the first lens produced using precision glass molding. Since the third and fourth lenses have a sufficient distance to at least one light source, they can be produced from plastic, a cheaper material compared to glass.

[0016] This makes the entire projection lens system not only cheaper to manufacture but also easier to design. In addition, the tolerance chain of the lenses relative to each other is reduced many times, since the first lens, which is designed to capture and collimate as much light as possible from at least one light source, is designed as a single lens based on its properties (and based on its large refractive index) in contrast to the prior art, which usually requires at least three or more lenses.

[0017] The first and second lenses are fabricated from glass because they are closest to the at least one light source and because glass is a material that has low thermal expansion.

[0018] Precision glass molding is a replication process that allows the production of high-precision optical components from glass without grinding or polishing. This process is also called precision glass pressing.

[0019] Additionally, at least one of the light sources may have a Lambertian radiation characteristic.

[0020] The third lens can be made of PC or PMMA.

[0021] The fourth lens can be made of PC or PMMA.

[0022] The second lens, the third lens, and the fourth lens may have a refractive index of n≦1.7.

[0023] The second lens may have an Abbe number of 60, and the third lens has an Abbe number of 23.

[0024] The second lens may have a higher Abbe number than the third lens, preferably the second lens has a higher Abbe number than the third lens by a ratio of 1:2.5, in particular 1:3.

[0025] The aperture may have an opening through which light can pass.

[0026] Thus, a high-resolution projection illumination device can be constructed.

[0027] The light distribution can be a low beam distribution and / or a high beam distribution.

[0028] The at least one light source may be configured as a plurality of light emitting diodes, which may preferably be arranged in a matrix arrangement of rows and columns.

[0029] In this case, the light-emitting diodes can be controllable independently of one another using a given control device, and in this case, the light-emitting diodes are preferably switchable and dimmable independently of one another.

[0030] The first lens, the second lens, the third lens, and the fourth lens may each have an optical axis, and in this case, the optical axes of these lenses are located on a common optical axis or coincide with one common optical axis.

[0031] The object is likewise achieved by a vehicle floodlight comprising at least one illumination device according to the invention.

[0032] The invention will now be explained in more detail with reference to the illustrative drawings. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 shows an illumination device according to the invention comprising a light source and a projection lens system for projecting the light of the light source. EXAMPLES

[0034] 1 shows an exemplary illumination device 10 for an automobile floodlight, which includes at least one light source 20 and a projection lens system 50 configured to project the light of the light source 20 in a light distribution in a main radiation direction X forward of the illumination device 10, the projection lens system 50 having a common focal point F, the at least one light source 20 being arranged at the common focal point F. The illumination device 10 is configured as an illumination device for high-resolution projection.

[0035] In this case, the projection lens system 50 includes a first lens 100 having a first focus, the first lens 100 being aspheric and manufactured from precision glass using precision glass molding, and disposed immediately after the light source 20 in the light path of the light source 20 as viewed in the main radiation direction X, the first lens 100 having a convex exit surface 110 and a concave entrance surface 120 for increasing the light incidence of the light of the light source 20, and configured to collimate the light of the light source 20 in the main radiation direction X, and the first lens 100 having a refractive index of n≧1.8.

[0036] In this case, the light source 20 has a Lambertian radiation characteristic, and in the illustrated example, is configured as a plurality of light emitting diodes arranged in a matrix arrangement of rows and columns.

[0037] The projection lens system 50 further comprises a second lens 200 having a second focal point, which is arranged immediately after the first lens 100 in the main radiation direction X and is configured as a spherical biconvex focusing lens, the second lens 200 being manufactured from glass by means of glass grinding and having an Abbe number of 60. (or an Abbe number greater than 60) has.

[0038] The projection lens system 50 further comprises a third lens 300 having a third focal point, which is arranged immediately after the second lens 200 in the main radiation direction X and is configured as an aspheric biconcave lens made of plastic, which has an Abbe number of 23. (or an Abbe number less than 25)The third lens 300 can be made from, for example, PC or PMMA plastic.

[0039] The projection lens system 50 further comprises a fourth lens 400 having a fourth focal point, which is arranged immediately after the third lens 300 in the main radiation direction X and which is configured as an aspheric biconvex converging lens made of plastic. The fourth lens 400 can be manufactured, for example, from PC or PMMA plastic.

[0040] For example, the third lens 300 and the fourth lens 400 can be made of PC or PMMA, or the third lens 300 can be made of PC and the fourth lens 400 can be made of PMMA, or vice versa, i.e. the third lens 300 can be made of PMMA and the fourth lens 400 can be made of PC.

[0041] In addition, the projection lens system 50 includes an aperture 500 disposed between the third lens 300 and the fourth lens 400, where the aperture 500 is configured to partially block light emitted from the third lens 300 in the direction of the fourth lens 400, so that the aperture 500 cooperates in forming a light distribution in front of the illumination device 10. In this case, the aperture 500 has an opening 510 through which the light emitted from the third lens 300 in the direction of the fourth lens 400 can at least partially pass.

[0042] For example, the light distribution is a low beam distribution and / or a high beam distribution.

[0043] Additionally, the second lens 200 and the third lens 300 are configured to cooperate as an achromatic lens pair LP1 to avoid chromatic aberration.

[0044] The third lens 300 and the fourth lens 400 have substantially the same thermal expansion coefficient, whereby the third lens 300 and the fourth lens 400 are configured to cooperate as an athermal lens pair (temperature-independent lens pair) LP2 to avoid displacement of the common focal point F at different temperatures.

[0045] Furthermore, the second lens 200, the third lens 300, and the fourth lens 400 have a refractive index of n≦1.7.

[0046] In addition, the first lens 100, the second lens 200, the third lens 300, and the fourth lens 400 each have an optical axis, and the optical axes of the first lens 100, the second lens 200, the third lens 300, and the fourth lens 400 are located on a common optical axis A or coincide with each other at a common optical axis A, as shown in FIG. 1. [Explanation of symbols]

[0047] 10 Irradiation device 20 light source 50 Projection Lens System 100 First lens 110 Exit surface 120 Entrance plane 200 2nd lens 300 3rd lens 400 4th lens 500 aperture 510 Opening LP1 Achromatic Lens vs. LP2 Athermal Lens Pair X Main radiation direction A Common optical axis F Common Focus

Claims

1. An illumination device for an automobile floodlight, comprising: The illumination device (10) includes at least one light source (20) and a projection lens system (50), the projection lens system (50) being configured to project light from the at least one light source (20) in a light distribution in front of the illumination device (10) in a main radiation direction (X), the projection lens system (50) having a common focal point (F), the at least one light source (20) being arranged at the common focal point (F), The projection lens system (50) consists of: a first lens (100) having a first focal point, said first lens (100) being aspheric, made of precision glass moulded precision glass and arranged immediately after said at least one light source (20) in the light path of said at least one light source (20) as viewed in said main radiation direction (X), said first lens (100) having a convex exit surface (110) and a concave entrance surface (120) for increasing the light incidence, said first lens (100) being configured to collimate the light of said at least one light source (20) in said main radiation direction (X), said first lens (100) having a refractive index n≧1.8, a second lens (200) having a second focal point, said second lens (200) being arranged immediately after said first lens (100) in said main radiation direction (X) and configured as a spherical biconvex collecting lens, said second lens (200) being made of glass ground and having an Abbe number greater than or equal to 60; a third lens (300) having a third focal point, said third lens (300) being arranged immediately after said second lens (200) in said main radiation direction (X) and being configured as an aspheric biconcave lens made of plastic, said third lens having an Abbe number smaller than 25; a fourth lens (400) having a fourth focal point, said fourth lens (400) being arranged immediately after said third lens (300) in said main radiation direction (X) and being constructed as an aspherical biconvex collecting lens made of plastic, a diaphragm (500) arranged between said third lens (300) and said fourth lens (400), said diaphragm (500) being arranged to partially block light emitted from said third lens (300) in the direction of said fourth lens (400), so that said diaphragm (500) cooperate in forming said light distribution in front of said illumination device (10); the second lens (200) and the third lens (300) are configured to cooperate as an achromatic lens pair (LP1) to avoid chromatic aberration; and the third lens (300) and the fourth lens (400) have the same thermal expansion coefficient, and the third lens (300) and the fourth lens (400) are configured to cooperate as an athermal lens pair (LP2) to avoid displacement of the common focal point (F) at different temperatures. An irradiation device characterized by:

2. the second lens (200), the third lens (300), and the fourth lens (400) have a refractive index of n≦1.7; The illumination device according to claim 1 ,

3. the second lens (200) has an Abbe number of 60 and the third lens (300) has an Abbe number of 23; The illumination device according to claim 1 ,

4. the second lens (200) has a higher Abbe number than the third lens (300), or the second lens (200) has a higher Abbe number than the third lens (300) by a ratio of 1:2.5 or 1:3; The illumination device according to claim 1 ,

5. The diaphragm (500) has an opening (510) through which light can pass; The illumination device according to claim 1 ,

6. The illumination device is configured as a high-resolution projection illumination device, The illumination device according to claim 1 ,

7. The light distribution is a low beam distribution and / or a high beam distribution; The illumination device according to claim 1 ,

8. the at least one light source (20) being configured as a plurality of light emitting diodes or as a plurality of light emitting diodes arranged in a matrix arrangement of rows and columns; The illumination device according to claim 1 ,

9. the first lens (100), the second lens (200), the third lens (300), and the fourth lens (400) each have an optical axis, and the optical axes of these lenses (100, 200, 300, 400) are located on a common optical axis (A) or coincide with one common optical axis; The illumination device according to claim 1 ,

10. A vehicle floodlight comprising at least one illumination device according to any one of claims 1 to 9.

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