US-20260126342-A1 - METHOD AND APPARATUS FOR TESTING COMPOSITE OPTICAL COMPONENTS

US20260126342A1US 20260126342 A1US20260126342 A1US 20260126342A1US-20260126342-A1

Abstract

The invention relates to a method and an apparatus for testing the optical properties of a composite optical component which includes a multiplicity of connected transparent elements and reflection layers which are arranged so that light introduced at an input portion is split in a first segment of the composite component with a plurality of transparent elements into a multiplicity of first partial beams, which are guided along different paths in the composite component. The first partial beams are partially reflected multiple times in a second segment which also includes a plurality of transparent elements, so that a plurality of second partial beams emerges from a side face due to the partial reflection. The second partial beams are recorded by a detector, and a quality coefficient is ascertained for a plurality of second partial beams selected according to an aggregation rule so the quality coefficient is assigned to a particular part of the composite component.

Inventors

Volker Hagemann
Sergej KUNZ
Steffen Richter

Assignees

SCHOTT AG

Dates

Publication Date: 20260507
Application Date: 20250911
Priority Date: 20240912

Claims (17)

1 . A method for testing the optical properties of a composite optical component, wherein the composite component comprises a multiplicity of transparent elements, which are connected to one another, and reflection layers, wherein the transparent elements and the reflection layers are arranged so that light introduced at an input portion is split in a first segment of the composite component comprising a plurality of transparent elements into a multiplicity of first partial beams, which are guided along different paths in the composite component, and wherein the first partial beams are partially reflected multiple times in a second segment, likewise comprising a plurality of transparent elements, in such a way that a plurality of second partial beams emerge from a side face due to the partial reflection, wherein the second partial beams are recorded by means of a detector, and a quality coefficient is ascertained from the signals of the detector for a plurality of second partial beams.
2 . The method according to claim 1 , wherein the plurality of second partial beams, from the signals of which the quality coefficient is ascertained, are selected according to an aggregation rule so that the quality coefficient can be assigned to a particular part of the composite component.
3 . The method according to claim 1 , wherein the second partial beams for ascertaining the quality coefficient are selected so that the light of these selected partial beams has been reflected at a particular reflection layer.
4 . The method according to claim 1 , wherein the quality coefficient is compared with a further quality coefficient, which is ascertained from a different set of second partial beams.
5 . The method according to claim 1 , wherein a superordinate quality coefficient is ascertained from at least two previously ascertained quality coefficients.
6 . The method according to claim 1 , wherein the composite optical component has a mixer segment, which is arranged between the first segment and the second segment and has a partially reflective reflection face lying parallel to the side face in the interior of the composite component, those second partial beams that are derived from a partial beam reflected at this reflection face being selected for the determination of the quality coefficient.
7 . The method according to claim 1 , wherein at least one of the following quality coefficients is determined: the modulation transfer function in at least one image direction, optionally color-dependent, a comparison, in particular a ratio, of the modulation transfer functions for two different image directions, angular deviations of the direction of the second partial beams, the transmission efficiency, in particular also color-dependent, a displacement of color coordinates, the dispersion in the emergent second partial beams, and/or the polarization of the second partial beams.
8 . The method according to claim 7 , wherein in order to determine the modulation transfer function for a second partial beam, an image having one or more test structures is introduced and the image in the second partial beam is recorded by a camera and evaluated in respect of the definition in two different image directions.
9 . The method according to claim 1 , wherein the signals of the second partial beams are weighted in order to ascertain the quality coefficient.
10 . An apparatus for carrying out the method according to claim 1 , comprising a mount for a composite component and a light source, which is arranged in relation to the mount so that light of the light source, which is introduced at an input portion of the composite component, is split in a first segment of the composite component comprising a plurality of transparent elements into a multiplicity of first partial beams, which are guided along different paths in the composite component, wherein the first partial beams are partially reflected multiple times in a second segment, likewise comprising a plurality of transparent elements, in such a way that a plurality of second partial beams emerge from a side face due to the partial reflection, wherein the apparatus comprises a detector in order to record the second partial beams, and an evaluation device, the evaluation device being configured to calculate a quality coefficient from the signals of the detector for a plurality of second partial beams, and for this purpose to select the plurality of second partial beams, from the signals of which the quality coefficient is ascertained, in particular according to an aggregation rule so that the quality coefficient can be assigned to a particular part of the composite component.
11 . The apparatus according to claim 10 , wherein the light source comprises a projector for transmitting images.
12 . The apparatus according to claim 10 , wherein the detector comprises a camera.
13 . The apparatus according to claim 10 , wherein the exit pupil of the light source is smaller than the entry pupil of the detector.
14 . The apparatus according to claim 13 , wherein the light source is a projector, and the detector is a camera.
15 . The apparatus according to claim 10 , wherein a movement device, with which the detector and the composite optical component can be moved relative to one another in order to position the detector at particular measurement positions in relation to the composite optical component.
16 . The apparatus according to claim 10 , wherein the detector comprises a camera, which is arranged at a distance from the side face of the composite component such that a plurality of partial beams are recorded simultaneously by the camera, and the plurality of partial beams are emerging with a spacing on the side face of at least 10 mm.
17 . The apparatus according to claim 16 , wherein the plurality of partial beams are emerging with a spacing on the side face of at least 15 mm.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority from German Patent Application No. 10 2024 126 197.8, filed Sep. 12, 2024, the disclosure of which is incorporated herein by reference. FIELD OF THE INVENTION The invention relates in general to the production of composite optical components comprising a multiplicity of optical elements, which are joined to one another and in which light is conveyed and deviated by reflexion. In particular, the invention relates to the testing of such composite optical components in respect of the optical quality of such components. BACKGROUND OF THE INVENTION So-called “augmented reality” applications use special spectacles which can overlay additional information items into the user's field of vision via optics. These information items are typically introduced via a projector into the spectacle lens, guided by light-guiding along the spectacle lens and subsequently output, and thus made visible to the user. Various optical elements, which are coupled to one another in the spectacle lens, are provided for the introduction, the light-guiding and the output. Such spectacle lenses are known for example from EP 1 562 066 B1, US 2023/0314689 A1 and WO 2021/001841 A1. These spectacle lenses, which are formed as image waveguides, may be produced by adhesively bonding a multiplicity of optical parts that have reflective, in particular partially reflective, layers with which the image information items, for example introduced via a projector, are split into a plurality of partial beams, guided in the waveguide and subsequently output in a distributed fashion so that the observer can perceive the image information in addition to the image of the environment. Both the geometrical accuracy of the individual parts and also, in particular, the formation of reflective layers and the mutual alignment of the parts may influence the optical properties of the waveguide in respect of the imaging quality. For example, the modulation transfer function (MTF) may be negatively influenced by tolerance-affected alignment and surface quality of individual parts and layers, which leads to a reduction of the image definition. Here, it would be desirable not only to determine quality factors such as the MTF, but in the event of a poor quality factor also to be able to ascertain which parts of the composite optical component are the cause. This is the object of the present invention. SUMMARY OF THE INVENTION In order to achieve the object, a method for testing the optical properties of a composite optical component is provided. The composite component comprising a multiplicity of transparent elements, which are connected to one another, and reflection layers, wherein the transparent elements and the reflection layers are arranged so that light introduced at an input portion is split in a first segment of the composite component comprising a plurality of transparent elements into a multiplicity of first partial beams, which are guided along different paths in the composite component, and wherein the partial beams are partially reflected multiple times in a second segment, likewise comprising a plurality of transparent elements, in such a way that a plurality of second partial beams emerge from a side face due to the partial reflection, wherein the second partial beams are recorded by means of a detector, anda quality coefficient is ascertained, in particular calculated, from the signals of the detector for a plurality of second partial beams, and whereinthe plurality of second partial beams, from the signals of which the quality coefficient is calculated, are preferably selected according to an aggregation rule so that the quality coefficient can be assigned to a particular part of the composite component. A corresponding apparatus for carrying out this method comprises a mount for a composite component and a light source, which is arranged in relation to the mount so that light of the light source, which is introduced at an input portion of the composite component, is split in a first segment of the composite component comprising a plurality of transparent elements into a multiplicity of first partial beams, which are guided along different paths in the composite component, wherein the partial beams are partially reflected multiple times in a second segment, likewise comprising a plurality of transparent elements, in such a way that a plurality of second partial beams emerge from a side face due to the partial reflection, wherein the apparatus comprises a detector in order to record the second partial beams, andan evaluation device, the evaluation device being configuredto calculate a quality coefficient from the signals of the detector for a plurality of second partial beams, and for this purpose to select the plurality of second partial beams, from the signals of which the quality coefficient is ascertained, in particular according to an aggregation rule so that th