DE102020131968A1 - Illumination with beam expansion - Google Patents

Illumination with beam expansion Download PDF

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Publication number
DE102020131968A1
DE102020131968A1 DE102020131968.1A DE102020131968A DE102020131968A1 DE 102020131968 A1 DE102020131968 A1 DE 102020131968A1 DE 102020131968 A DE102020131968 A DE 102020131968A DE 102020131968 A1 DE102020131968 A1 DE 102020131968A1
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DE
Germany
Prior art keywords
diffuser
illumination
beam expansion
light
source
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
DE102020131968.1A
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German (de)
Inventor
Thomas Dietz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
IFM Electronic GmbH
PMDtechnologies AG
Original Assignee
IFM Electronic GmbH
PMDtechnologies AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by IFM Electronic GmbH, PMDtechnologies AG filed Critical IFM Electronic GmbH
Priority to DE102020131968.1A priority Critical patent/DE102020131968A1/en
Publication of DE102020131968A1 publication Critical patent/DE102020131968A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
    • F21V9/14—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters for producing polarised light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • G02B27/0905—Dividing and/or superposing multiple light beams
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • G02B27/0938—Using specific optical elements
    • G02B27/095—Refractive optical elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0278—Diffusing elements; Afocal elements characterized by the use used in transmission
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/30—Semiconductor lasers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/005—Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/18—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
    • H01S5/183—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]

Abstract

Beleuchtung mit einer Lichtquelle, einem Diffusor und einem doppelbrechenden optischen Element,wobei das doppelbrechende optische Element zwischen der Lichtquelle und dem Diffusor angeordnet ist.Illumination with a light source, a diffuser and a birefringent optical element, the birefringent optical element being arranged between the light source and the diffuser.

Description

Die Erfindung betrifft eine Beleuchtung, bei der das von den Lichtquellen ausgestrahlte Licht über ein doppelbrechendes Medium und einem Diffusor aufgeweitet wird.The invention relates to lighting in which the light emitted by the light sources is expanded via a birefringent medium and a diffuser.

Typischerweise werden VCSEL nur mit dem durch das Bauelement vorgegebenen Öffnungswinkel betrieben. Dies führt bei einer vorgenommenen Vergrößerung der Abstrahlfläche zu signifikant erhöhtem Bauraumbedarf und gefalteten Optiken mit komplizierten Spiegelarrays.Typically, VCSELs are only operated with the opening angle specified by the component. If the radiating surface is enlarged, this leads to a significantly increased installation space requirement and folded optics with complicated mirror arrays.

Kerngedanke der Erfindung ist es eine Möglichkeit zur optischen Quellenvergrößerung zu schaffen, die im Rahmen des augensicheren Betriebs von Laserprodukten gemäß des internationalen Standards IEC 60825-1 bleibt.The core idea of the invention is to create a possibility for optical source enlargement that remains within the scope of the eye-safe operation of laser products in accordance with the international standard IEC 60825-1.

Um die Augensicherheit zu gewährleisten, darf die optische Quellengröße, definiert als der Winkel, der vom Betrachtungspunkt aus vom strahlenden Objekt überstrichen wird, einen bestimmten Grenzwert nicht unterschreiten. Dieser Grenzwert hängt von der Beleuchtungsdauer sowie der emittierten optischen Leistung ab. Dabei besteht die Abhängigkeit, dass, je größer die Quellengröße ist, desto größer auch optische Leistung und / oder die Beleuchtungsdauer sein darf. Eine größere optische Leistung kann von Interesse sein, um ein besseres Signal- zu Rauschverhältnis zu erhalten. Folglich ist es von Interesse die optische Quelle zu vergrößern. Die Beleuchtungseinheit besteht aus einer Laserdiode und einem Diffusor. Als Referenzpunkt zur Bestimmung der Quellengröße darf bei vollständig diffusem Licht die Oberfläche des Diffusors herangezogen werden, sodass die Quellengröße durch die beleuchtete Fläche des Diffusors bestimmt wird.To ensure eye safety, the optical source size, defined as the angle swept by the radiating object from the viewing point, must not fall below a certain limit. This limit value depends on the lighting duration and the emitted optical power. There is the dependency that the larger the source size, the greater the optical power and/or the duration of illumination may be. Greater optical power may be of interest to get better signal-to-noise ratio. Consequently, it is of interest to increase the size of the optical source. The lighting unit consists of a laser diode and a diffuser. The surface of the diffuser may be used as a reference point for determining the source size in the case of completely diffuse light, so that the source size is determined by the illuminated area of the diffuser.

Die erfindungsgemäße Lösung besteht darin, zwischen die Laserdiode (VCSEL) und einem Diffusor ein doppelbrechendes Medium einzubringen. Ein doppelbrechendes Medium weist hierbei in zwei verschiedenen Raumrichtungen unterschiedliche Brechungsindizes auf.The solution according to the invention consists in introducing a birefringent medium between the laser diode (VCSEL) and a diffuser. A birefringent medium has different refractive indices in two different spatial directions.

Fällt unpolarisiertes Licht (Polarisationskomponenten sind statistisch verteilt) in ein solches Medium ein, werden zwei orthogonale Polarisationskomponenten in unterschiedliche Richtungen innerhalb des Mediums gebrochen. Unpolarisiertes Licht teilt sich folglich zu gleichen Teilen auf diese Richtungen auf. Nach dem Austritt der Strahlung aus dem Medium ergibt sich daher ein Doppelbild der Laserdiode auf dem Diffusor, wodurch die optische Quelle vergrößert wird.When unpolarized light (polarization components are statistically distributed) is incident on such a medium, two orthogonal polarization components are refracted in different directions within the medium. Unpolarized light is therefore divided equally between these directions. After the radiation exits the medium, the laser diode produces a double image on the diffuser, which increases the size of the optical source.

Als doppelbrechende Medien kommen verschiedene Materialien in Betracht. Zum einen existieren natürliche Kristalle mit dieser Eigenschaft (siehe z. B. Kalzit), sie können aber auch künstlich hergestellt werden. Ebenso wäre es denkbar, eine Doppelbrechung in einem Kunststoff durch mechanische Spannung zu induzieren (photoelastischer Effekt).Various materials can be considered as birefringent media. On the one hand, there are natural crystals with this property (see e.g. calcite), but they can also be produced artificially. It would also be conceivable to induce birefringence in a plastic through mechanical stress (photoelastic effect).

In 1 links ist eine aus dem Stand der Technik bekannte Beleuchtung gezeigt, bei der das von der Lichtquelle (VCSEL) abgestrahlte Licht über einen Diffusor aufgeweitet wird.In 1 Illumination known from the prior art is shown on the left, in which the light emitted by the light source (VCSEL) is expanded via a diffuser.

1 rechts zeigt eine erfindungsgemäße Lösung bei der das unpolarisierte Licht der Lichtquelle über ein doppelbrechendes Medium in zwei polarisierte Teilstrahlen aufgeteilt wird und hiernach über einen Diffusor aufgeweitet wird. 1 on the right shows a solution according to the invention in which the unpolarized light of the light source is divided into two polarized partial beams via a birefringent medium and is then expanded via a diffuser.

Claims (1)

Beleuchtung mit einer Lichtquelle, einem Diffusor und einem doppelbrechenden optischen Element, wobei das doppelbrechende optische Element zwischen der Lichtquelle und dem Diffusor angeordnet ist.Illumination with a light source, a diffuser and a birefringent optical element, the birefringent optical element being arranged between the light source and the diffuser.
DE102020131968.1A 2020-12-02 2020-12-02 Illumination with beam expansion Withdrawn DE102020131968A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE102020131968.1A DE102020131968A1 (en) 2020-12-02 2020-12-02 Illumination with beam expansion

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102020131968.1A DE102020131968A1 (en) 2020-12-02 2020-12-02 Illumination with beam expansion

Publications (1)

Publication Number Publication Date
DE102020131968A1 true DE102020131968A1 (en) 2022-06-02

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DE102020131968.1A Withdrawn DE102020131968A1 (en) 2020-12-02 2020-12-02 Illumination with beam expansion

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DE (1) DE102020131968A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE60032127T2 (en) 1999-04-05 2007-10-25 Sharp K.K. SEMICONDUCTOR LASER DEVICE AND ITS MANUFACTURING METHOD, OPTICAL COMMUNICATION SYSTEM AND OPTICAL SENSOR SYSTEM
JP2014174442A (en) 2013-03-12 2014-09-22 Ricoh Co Ltd Illumination light source device and projection device using the same
US20170082913A1 (en) 2015-09-18 2017-03-23 JVC Kenwood Corporation Optical device and projecting device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE60032127T2 (en) 1999-04-05 2007-10-25 Sharp K.K. SEMICONDUCTOR LASER DEVICE AND ITS MANUFACTURING METHOD, OPTICAL COMMUNICATION SYSTEM AND OPTICAL SENSOR SYSTEM
JP2014174442A (en) 2013-03-12 2014-09-22 Ricoh Co Ltd Illumination light source device and projection device using the same
US20170082913A1 (en) 2015-09-18 2017-03-23 JVC Kenwood Corporation Optical device and projecting device

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R163 Identified publications notified
R119 Application deemed withdrawn, or ip right lapsed, due to non-payment of renewal fee