DE102010055939A1 - Dyeing a glass or, preferably different optical glasses, comprises carrying out first dyeing, determining color difference from predetermined desired color, providing dyeing model, and performing second dyeing process with determined values - Google Patents

Abstract

Dyeing a glass comprises carrying out a first dyeing process of the glass; determining a color difference of an attained glass coloration from a predetermined desired color in a specific color space; providing a dyeing model for the predetermined target color, which changes the glass coloring in the specific color space; determining values of the process parameters of the second dyeing process in such a way that the values associated with changes represents an at least partial compensation of the determined color difference; and performing the second dyeing process with the determined values. Dyeing a glass comprises (a) carrying out a first dyeing process of the glass, (b) determining a color difference of an attained glass coloration from a predetermined desired color in a particular color space, (c) providing a dyeing model in accordance for the predetermined target color, which changes the glass coloring in the specific color space, based on the predetermined desired color, depending on the process parameters, represents a second dyeing process, (d) determining values of the process parameters of the second dyeing process in such a manner that the values of process parameters to be determined by the dyeing model associated with change in glass coloring based on the attained glass coloration represents an at least partial compensation of the determined color difference, and (e) carrying out the second dyeing process with the determined values of process parameters. Independent claims are also included for: (1) creating a dyeing model comprising (a) manufacturing a common target color corresponding to manufacturing a variety of glasses, their color, (b) applying a second dyeing process in each case of multiple glasses, each with a reference value for multiple process parameters of the second dyeing process, where the glasses in pairs each, differs the reference value of at least one process parameter, and (c) detecting a second dyeing process resulted by the changes in the glass color for each of the multiple glasses in a specific color space; (2) a system for determining process parameters for dyeing the glass comprising (1) a color analysis module for determining the color difference of the glass coloring with a determined target color in the specific color space, attained in a first dyeing process, (2) a data storage for providing a model dyeing for the predetermined target color, which represents the basis of the predetermined desired color changes in the glass coloring in the specific color space depending on process parameters of a second dyeing process, (3) a parameter evaluation module for determining values of the process parameters of the second dyeing process in such a manner that the values of process parameters to be determined by the dyeing model associated with change in glass coloring based on the attained glass coloration represents an at least partial compensation of the determined color difference, and (4) a data output module for outputting the determined values of the process parameters; and (3) a computer program product comprising loading program code, and causing execution by the computer system to determine the process parameters for coloring the glass that includes (1a) determining a deviation of a color attained glass coloration of a predetermined target color in a specific color space in a first dyeing process, (1b) providing a dyeing model for the predetermined target color, which represents the basis of the predetermined desired color changes in the glass staining in the color space as a function of process parameters of a second dyeing process, (1c) determining values of the process parameters of the second dyeing process, and (1d) outputting the determined values of process parameters.

Description

More particularly, the present invention relates to a method and system for coloring glasses.

Conventionally, glasses, such as. As spectacle lenses or other optical glasses, often dyed by wet chemical diffusion method using aqueous, dye-containing immersion baths. Such dye baths are usually operated at temperatures between about 80 ° C and 100 ° C. The coloring of the glasses is achieved by immersing the lenses in the dyebath and by diffusing the dyes into the plastic during the residence time in the dyebath.

In particular, when the dyeing is done by hand, the glass to be dyed is dipped in the dyebath for a certain time by an experienced dyer and inspected immediately after removal from the dyebath. If the desired color intensity has not yet been reached, the glass is again immersed in the dyebath. This is optionally repeated until the desired color intensity of the glass is reached. In order to come as close as possible to the desired target color and intensity, a lot of experience is needed. Automated automation of this process is very difficult, since these wet-chemical diffusion processes usually have high non-linearities in the color change upon repeated immersion in the dyebath. In particular, if the desired color intensity has been exceeded by more than a tolerable deviation, the glass must be discarded. In particular, for glasses with a high refractive index, it is also often difficult to achieve sufficient diffusion of the dye into the glass at the available temperatures of below 100 ° C already.

In a further known dyeing process, the so-called thermal transfer process, the dyes are applied to a glass by sublimation and then diffused in an annealing step (heating of the glass) in the plastic. In particular, the dyes are first printed on a thermal transfer paper. The printed paper is then placed in particular without direct contact with the glass over the glass surface to be colored. In a vacuum chamber, the color is sublimated by heating the printed paper. The thus deposited on the glass color is then fixed in an annealing step, wherein the color diffuses into the glass. If too many deviations from the targets occur during dyeing, the glass must be discarded.

The object of the invention is to increase the yield of usable glasses during dyeing, without having to raise the tolerance for deviations from the target specifications of the glass color to be achieved. This object is achieved by a method for coloring a glass or a method for creating a Nachfärbemodells and a system for determining process parameters and a computer program product having the features specified in the claims 1, 10, 14 and 15 respectively. Preferred embodiments are subject of the dependent claims.

Thus, the invention provides in particular in processes for dyeing a glass, in particular spectacle lens ready. The method comprises performing a first dyeing process for the glass. This first dyeing process is preferably based on a substantially uncolored glass and is carried out with the objective to achieve a certain target color of the glass. For this purpose, the first dyeing process is carried out with corresponding process parameters, which, according to the instructions or experience, should lead to the desired target color.

Due to process conditions that are not completely controllable, however, even with nominally identical process parameters, slightly different, resulting colorations of the glass may occur during the first dyeing process, which deviate more or less from the desired target coloration in particular. In order to be able to quantify this color deviation, the method comprises determining the color deviation of the glass coloration achieved after the first dyeing process from the desired coloration in a specific color space. The color space used is spanned by a corresponding set of color space parameters, so that each possible glass coloration is preferably uniquely determined by corresponding values of the color space parameters. Thus, determining the color deviation comprises, in particular, determining values achieved in the first coloring process for the set of color space parameters in the specific color space. These values of the color space parameters define a point in the multidimensional color space, which is also referred to here as a "color location".

Particularly preferably, determining the values achieved in the first staining process for the set of color space parameters in the determined color space comprises measuring the transmittivity of the glass for light. In particular, preferably a continuous or quasi-continuous spectrum of the transmittivity of the glass for light, in particular in the visible spectral range and / or in the UV-A range and / or in the UV-B range and / or in the UV-C range. From the measured transmissivity, the values achieved for the set of color space parameters in the specific color space are then preferably taken directly or determined by parameter adaptation. For example, at least some of the color space parameters of the particular color space could describe the physiological color and transmission perception of the human eye. These parameters are then preferably calculated from the measured transmissivity, in particular the measured transmission spectrum.

Preferably, the predetermined desired color is specified as the color location in the color space used, d. H. in particular setpoint values for the color space parameters are specified. Now, a color deviation is preferably determined as deviations of the values achieved from the nominal values of the color space parameters. Preferably, a color deviation vector or color error vector is determined, the components of which represent the differences between the desired values or target values and the actually achieved values (actual values) of the color space parameters.

In particular, a metric belongs to the color space used, or a metric is assigned to the color space which always assigns a distance to two points of the color space, that is to say two color locations, in particular in order to quantify a color deviation. In particular, a standard is defined on the color space, which specifies in particular the length of the color deviation vector or color error vector. For example, the Euclidean norm or the maximum norm serves for this purpose. The resulting from this metric or norm length of the color deviation vector or color error vector thus forms a measure of the color deviation (that is, a measure of color error).

According to the invention, a replication model is provided for the predetermined desired color, which, starting from the predefined desired color, represents changes in the glass coloration, ie the color space parameters in the specific color space as a function of process parameters of a second dyeing process. The Nachfärbemodell represents a rule that assigns a change in the glass color in the form of a change in the color space parameters in particular from the target color each set of values for the process parameters of the second dyeing process. Although this rule, which is provided for the given target coloration, depends on the process parameters of the second dyeing process, it preferably does not contain any (explicit) dependence of the color change on the color location, which serves as a starting point for the color change. The replenishing model provided thus describes the color space used as linear or translation-invariant in this sense, at least locally, that is to say in the vicinity of the specific desired coloration. The model thus represents an approximation in that the behavior of the dyeing process is described as being linear or translationally invariant, at least in a region around the desired color. H. The relationship between the values of the process parameters and the color change described by the model is a starting point for the re-dyeing process or the second dyeing process, irrespective of the color locus reached. Although the described relationship is ideally valid only for a single starting point and then possibly only for very small color changes, the invention makes good use of the good approximation by the coloring model in the entire environment around the predetermined target color around.

Taking into account the determined color deviation, values of the process parameters of the second dyeing process are determined on the basis of the replenishment model provided, such that the change in glass coloration attributable to the values of the process parameters to be determined based on the glass coloration achieved after the first dyeing process at least partially compensates for the color change represents determined color deviation. The "at least partial compensation of the determined color deviation" is understood to mean that, starting from the glass coloration achieved in the first dyeing process, a further change in the glass coloration according to the change determined by the (linear) replenishment model leads to a smaller color deviation than the desired color as the determined color deviation after the first coloring process, the amount of color deviation being defined by the metric or norm associated with the color space. The determination of the values of the process parameters is carried out in particular computer-assisted by a corresponding numerical calculation method.

Particularly preferably, the color deviation is optimally or even completely compensated within the scope of a given optimization accuracy by the determined values of the process parameters of the second dyeing process, ie the change in glass coloration associated with the determined values of the process parameters by the replenishment model is as similar as possible to the initial color deviation within the given optimization accuracy good or even complete. There may be situations in which a complete compensation of the determined color deviation by a second dyeing process itself is theoretically impossible. Especially if already too much of at least one color was transferred to the glass or was applied, the glass was already colored as in particular already too dark, the compensation in the form of a sufficient brightening of the glass in a second dyeing step may not be achievable. In this case, the best possible compensation is determined in particular within the scope of the specified optimization accuracy.

Finally, the second dyeing process is carried out with the determined values of the process parameters. This allows many glasses, which reach not required tolerances for the coloration after the first dyeing process in the second dyeing process can be corrected very accurately. The yield of usable glasses is thus significantly increased over conventional methods for dyeing glasses, without having to raise the tolerance for deviations from targets of the glass to be achieved glass. On the other hand, while maintaining the yield, the quality requirements in terms of color tolerance can be substantially increased.

The first and / or second dyeing process preferably comprises a sublimation process, in particular a thermal transfer process, and / or a spray process. Preferably, at least in the second dyeing process, more preferably in the first and in the second dyeing process, no dyeing dip is used. In particular, it has been recognized within the scope of the invention that just dyeing by means of immersion baths to comparatively large non-linearities with regard to the relationship between the process parameters used, such. As the dipping time, the dye concentration, the number of dyeing steps (repeated or repeated dipping operations), etc., and the achieved, effective glass coloration leads. In particular, by the use of sublimation (especially in the form of a thermal transfer process) and / or spraying the yield of glasses can be significantly increased using a method according to the invention. In these methods, the dyeings to be achieved by the present invention can be realized very accurately and reproducibly.

Preferably, a plurality of (linear) resurfacing models are provided, each associated with a particular glass material. These Nachfärbemodelle are preferably stored in a database and automatically selected depending on the material of the glass to be colored. This is the fact that changes in the glass colorations in the particular color space at the same parameters of a second dyeing process may depend at least partially on the material of the lens to be dyed. Thus, the material-dependent dyeing behavior, in particular the material-dependent assumption of the color and the material-dependent optical color effect of the dyes used can be considered very accurately. In a further aspect, preferably a plurality of (linear) replication models are provided, each of which is associated with a particular target coloration. These Nachfärbemodelle are preferably stored in a database and automatically selected depending on the target color of the glass to be dyed. Thus, non-linear relationships between the amount of each applied color and its optical effect or its influence on at least one color space parameter can be considered very accurately.

The CIELAB color space and / or the XYZ color measurement space and / or the YCC color model and / or the RGB color space and / or the sRGB color space and / or another linear color space are preferably used as the specific color space.

Preferably, the process parameters of the second dyeing process comprise a plurality of primary color parameters (preferably at least three, more preferably exactly three primary color parameters), each of which specifies a color amount of a color from a set of primary colors used in the second dyeing process. The process parameters of the second dyeing process also particularly preferably comprise a multiplicity of color combination parameters, each of which at least partially determines (ie quantifies) a combination of at least two primary colors from the set of primary colors used or used in the second dyeing process. The individual process parameters are thus not necessarily independent of each other. Rather, in this case, a color combination parameter depends in particular directly on at least two primary color parameters. Thus, a color combination parameter could preferably be provided as a product or as a sum of at least two primary color parameters. In this way, an interaction of different primary colors can be considered in a very efficient manner with comparatively low computational effort. Thus, even under difficult to control process conditions, a particularly good precision of the dyeing process in terms of adaptation to the targets is achieved.

Preferably, the reticle model is provided such that it changes the glass coloration in the particular color space as a linear combination of the process parameters of the second dyeing process represents. In particular, the changes in the color parameters in the particular color space are thus represented as linear combinations of the process parameters of the second dyeing process. This enables a particularly fast and efficient computer-aided determination of values of the process parameters for the second dyeing process.

For determining values of the process parameters of the second dyeing process, the process parameters are preferably varied in succession such that in each case at least one process parameter of the second dyeing process is varied to improve the at least partial compensation of the determined color deviation, while at least one other process parameter remains unchanged. In particular, the respectively at least one process parameter is varied in such a way that the amount of the expected color deviation predicted by the replication model is reduced or minimized after the subsequent coloration. After a minimum for the amount of color deviation has been found within the selected numerical accuracy, the determined value for the respectively at least one process parameter is recorded and another, previously recorded or unchanged process parameter varies accordingly by the amount of the expected color deviation reduce or minimize.

The method thus comprises, in particular, a first minimization step for minimizing the amount of the expected color deviation by varying at least one first process parameter, while at least one second process parameter remaining unchanged from the first independent process parameter remains fixed. The first minimization step comprises in particular a determination of that value of the first process parameter which, given unchanged values of the further process parameters independent of the first process parameter, leads to a minimum of the amount of the expected color deviation within the framework of the selected numerical accuracy. In particular, a first primary color parameter is varied as at least one first process parameter, while a second primary color parameter remains unchanged. If appropriate, color combination parameters taken into account in the replication model are varied accordingly, insofar as they depend on the first basic color parameter.

The method preferably then comprises at least one second minimization step for minimizing the amount of the expected color deviation by varying at least one second, from the first independent process parameter, while the at least one first process parameter remains unchanged, ie fixed. The second minimization step comprises in particular a determination of that value of the second process parameter which, given unchanged values of the further process parameters independent of the second process parameter, leads to a minimum of the amount of the expected color deviation within the framework of the selected numerical accuracy. In particular, a second primary color parameter is varied as at least one second process parameter, while the first primary color parameter remains unchanged. If appropriate, color combination parameters taken into account in the replication model are varied accordingly, insofar as they depend on the second basic color parameter.

Preferably, the method comprises a plurality of corresponding minimization steps for the respective independent process parameters (eg basic color parameters). Most preferably, the minimization steps are performed iteratively, i. H. the process parameters of the second dyeing process are preferably iteratively varied successively.

Preferably, the method comprises checking whether the determined color deviation is within a tolerance range, determining values of the process parameters of the second coloration process and performing the second colorization process only if the determined color deviation is not within the tolerance range. Preferably, an amount of the color deviation is determined, wherein the amount of the determined color deviation is evaluated in particular on the basis of the standard selected for the particular color space (eg Euclidean norm or maximum norm). In this case, a range of values of the amount of color deviation or value ranges for the deviation of individual color space parameters could be specified as the tolerance range. Preferably, the checking is carried out automatically, in particular in a system which is also provided by the invention, as shown in more detail below. For this purpose, the tolerance range is preferably provided or defined in a data memory of the system. Checking whether the detected color deviation is within a tolerance range, and in particular determining the amount of color deviation, is preferably performed by a color evaluation module of the system.

Preferably, the method comprises checking whether the change in the glass coloration associated with the determined values of the process parameters by the replenishing model, based on the achieved glass coloration, leads to a predicted color deviation which is within a tolerance range Performing the second dyeing process only occurs when the predicted color deviation is within the tolerance range. The predicted color deviation corresponds to the color deviation from the predefined desired coloration which is expected on account of the replication model after the second dyeing process. Preferably, an amount of the predicted color deviation is determined, which is evaluated in particular on the basis of the standard selected for the specific color space (eg Euclidean norm or maximum norm). Preferably, the checking is carried out automatically, in particular in a system which is also provided by the invention, as shown in more detail below. Checking whether the determined color deviation lies within a tolerance range, and in particular determining the amount of color deviation, is preferably carried out by a parameter evaluation module of the system. If checking is carried out in particular after a complete determination of the values of the process parameters has already taken place, if in particular the best possible approximation to the desired color has already been predicted. If no color is achieved, which is still tolerable, the glass is preferably discarded. In particular, the second dyeing process is not performed at all.

In another aspect, the invention provides a method for creating a replication model. This method involves preparing a plurality of glasses whose staining corresponds to a common target stain (target staining), d. H. whose color does not differ by more than a specified tolerance of target values for the parameters of an applied parameter space. The glasses are preferably similar in terms of material, geometry, manufacture and the dyeing process, including any post-treatment. Thus, the influences of subsequent process steps in which the glasses differ at least partially, can be separated very well.

In addition, the method comprises applying a second dyeing process (subsequent dyeing) to each of the plurality of glasses each having a reference value for a plurality of process parameters of the second dyeing process, wherein the glasses differ in pairs in each case in the reference value of at least one process parameter. In particular, a color amount or a combination of color amounts or the value zero, if a color is not used in the corresponding second dyeing process, is specified as the reference value for each of the process parameters.

In addition, the method includes determining a change in glass coloration for each of the plurality of glasses in a particular color space caused by the second coloration process. The color space used is spanned by a corresponding set of color space parameters, so that each possible glass coloration is preferably uniquely determined by corresponding values of the color space parameters. Thus, determining the effected changes in the glass color includes determining changes in the values for the set of color space parameters in the particular color space.

Thus, the method describes an assignment of reference values of the individual process parameters to the changes of the individual color space parameters. This assignment thus provides coefficients of the Nachfärbemodells. In particular, the re-staining model is created as a set of coefficients that defines the changes in the glass coloration as linear combinations of the reference values of the process parameters. That is, the detected changes in glass color are expressed as linear combinations of the reference values of the process parameters whose coefficients form the coefficient set of the replicate model. In this case, the coefficient set of the Nachfärbemodells is preferably represented as a model matrix, while the plurality of process parameters are represented as coefficients of a process vector and the color space parameters as coefficients of a color space vector. In particular, if the process vector contains m components and the color space vector contains n components, the model matrix is preferably represented as an (m × n) matrix, the product of the model matrix and the process vector leading to the color space vector corresponding to the determined change in the glass coloration.

The replenishment model produced according to the invention is preferably provided as a staining model for a staining of a glass according to the invention. For this purpose, dyeing a glass or, preferably, a large number of glasses according to the invention also includes, in particular, at least one inventive creation of a replication model.

Preferably, individual primary colors are used for at least some of the glasses in the second dyeing process. Thus, for at least two glasses, particularly preferably for three glasses, different primary colors are preferably used individually in each case in a reference quantity, and their effect with respect to the change in the glass color is determined. Thus, applying a second dyeing process preferably comprises applying a dyeing process to a first reference color of a first base color to a first glass; and / or applying a dyeing process to a second reference amount of a second Base color on a second glass; and / or applying a dyeing process with a third reference amount of a third base color to a third glass.

Particularly preferably, combinations of two or more primary colors are used for at least some of the glasses in the second dyeing process. Thus, preferably for at least two glasses, particularly preferably for three glasses, different combinations of primary colors are each used in a reference amount, and their effect with respect to the change in the glass color is determined. Thus, applying a second dyeing process preferably includes applying a dyeing process to the first reference amount (or a first combination reference amount) of the first base color and the second reference amount (or a second combination reference amount) of the second base color to a fourth glass; and / or applying a dyeing process to the first reference amount (or a first combination reference amount) of the first base color and the third reference amount (or a third combination reference amount) of the third base color to a fifth glass; and / or applying a dyeing process to the second reference amount (or a second combination reference amount) of the second base color and the third reference amount (or a third combination reference amount) of the third base color to a sixth glass. Thus, interactions of several colors on the color of the glass can be examined in a particularly efficient manner. As far as the combinations of primary colors are applied in parallel to the individual primary colors, the reference quantities of the individual colors in the combination of several colors do not have to match the applied reference quantities of the corresponding colors in their individual application. Rather, when using combinations of several colors, other known reference quantities (combination reference amounts) of the respective colors could be used.

The second dyeing process preferably takes place for at least one of the plurality of glasses without the addition of color. This can be used to determine what influence other process parameters, such. B. has the heating (in particular tempering) of the glass for fixing paint on the change of the glass color.

The determination of the values of the process parameters is preferably computer-assisted by a corresponding numerical calculation method. Accordingly, in one aspect, the invention provides a system for determining process parameters for coloring a glass. The system comprises a color evaluation module for determining the color deviation of the glass coloration achieved in the first dyeing process from the predetermined desired coloration for the glass in the specific color space. In addition, the system comprises a data memory for providing the Nachfärbemodells for the predetermined target color, which represents, starting from the predetermined target color changes in the glass coloration in the particular color space as a function of process parameters of the second dyeing process.

In addition, the system comprises a parameter evaluation module (in particular as a numerical module of a computer system) for determining values of the process parameters of the second dyeing process such that the change in glass coloration associated with the values of the process parameters to be determined by the replenishment model results in at least partial compensation of the determined glass coloration Represents color deviation. In addition, the system includes a data output module for outputting the determined values of the process parameters. The data output module preferably comprises a graphical output interface for outputting to a user the determined values of the process parameters, and / or a control interface for transmitting the determined values of the process parameters directly to a staining module for controlling the second staining process.

In this case, the system preferably also includes the staining module, which is designed to automatically perform the second staining process in accordance with the determined values of the process parameters. The color evaluation module preferably comprises a transmission spectrometer for determining the glass coloration achieved in the first dyeing process.

• – Ermitteln einer Farbabweichung einer in einem ersten Färbeprozess erreichten Glasfärbung von einer vorgegebenen Sollfärbung für das Glas in einem bestimmten Farbraum;
• – Bereitstellen eines Nachfärbemodells für die vorgegebene Sollfärbung, welches ausgehend von der vorgegebenen Sollfärbung Änderungen der Glasfärbung in dem bestimmten Farbraum in Abhängigkeit von Prozessparametern eines zweiten Färbeprozesses darstellt;
• – Bestimmen von Werten der Prozessparameter des zweiten Färbeprozesses derart, dass die durch das Nachfärbemodell den zu bestimmenden Werten der Prozessparameter zugeordnete Änderung der Glasfärbung ausgehend von der erreichten Glasfärbung eine zumindest teilweise Kompensation der ermittelten Farbabweichung darstellt; und
• – Ausgeben der bestimmten Werte der Prozessparameter.

In addition to corresponding methods for dyeing a glass involving one or more of the corresponding method steps implemented as functional processes in the systems according to the invention, the invention also provides a computer program product, in particular in the form of a storage medium or a signal sequence, comprising computer-readable instructions which, when loaded into a memory a computer and executed by the computer cause the computer to perform a method according to the present invention, in particular in a preferred embodiment. Thus, the invention particularly provides a computer program product comprising program code which, when loaded and executed by a computer system, causes it to execute a method for determining process parameters for coloring a glass, comprising the steps of:

• Determining a color deviation of a glass coloration achieved in a first dyeing process from a predetermined target color for the glass in a specific color space;
• - Providing a Nachfärbemodells for the predetermined target color, which represents, starting from the predetermined target color changes in the glass coloration in the particular color space as a function of process parameters of a second dyeing process;
• Determining values of the process parameters of the second dyeing process in such a way that the change in the glass coloration associated with the values of the process parameters to be determined, based on the achieved glass coloration, represents an at least partial compensation of the determined color deviation; and
• - Output of the determined values of the process parameters.

The invention will be described by way of example with reference to accompanying drawings of preferred embodiments. Showing:

1 a schematic representation of an exemplary color space according to a preferred embodiment of the invention;

2 and 3 schematic representations for applying a provided Nachfärbemodells in the preferred color space of 1

1 shows a schematic representation of a preferred color space. In particular, in the preferred embodiment shown here, the CIELAB color space (in particular also referred to as CIE 1976 (L * a * b *) color space) is used. This is in particular on the DIN 6174 referred, whose designs and definitions of the chosen color space particularly preferred in the context of the present invention find application. The in 1 schematically shown color space is spanned by three coordinates (a *, b *, T) and / or (a *, b *, L *), in particular according to the CIELAB color space (DIN 6174) or the transmission according to the DIN 1836 can be fixed. Here, a * and b * form coordinates of the hue, while L * characterizes the sensitively perceived brightness or T weighted the transmissivity of the glass according to the spectral sensitivity of the eyes. The standardized color space has the same effect in perception, ie equal Euclidean distances correspond approximately to the same color distances, and it is device-independent. Every perceptible color in the color space is defined by the color locus with the coordinates (a *, b *, T). In application of the counter-color theory, green and red lie opposite each other on the a * -axis. The b * -axis corresponds to the opposite colors blue and yellow. Unlike CIELAB, preferably a *, b * according to CIELAB is used here, as well as the transmittance T according to DIN 1836, in which T (LTM): = 100 · τ _{ν = 0.01} · Στ (λ) · S _D65λ (λ) · ν _λ (λ) is defined.

The in 1 illustrated crossing point of the three axes A _{a *} , A _{b *} and A _T , which run parallel to the coordinate axes of a *, b * and T represents a color location to be reached, ie a target color 10 , The target color 10 is clearly defined by the three coordinates in the chosen color space and represents the desired color of a glass to be colored by a method according to the invention. To the desired color 10 around is schematically a tolerance range 12 represented in the form of a cube. The tolerance range 12 sets the allowable range, which is still considered an acceptable tolerance. In particular, the tolerance range defines 12 the maximum permissible deviations from the target color 10 firmly. The embodiment described here could also be implemented with another form of the tolerance range, which can be represented, for example, as a sphere in the color space around the desired color.

Will now a glass in a first dyeing process with the targets to achieve the target color 10 colored, it may - especially due to not precisely controllable process parameters - come to a glass coloration, which is not exactly the target color 10 equivalent. The glass is thus measured after the first dyeing process, preferably by means of a colorimeter (spectrometer). The colorimetric data obtained are recorded in units of a * and b * and T (LTM transmission). In the in 1 The color space shown is also the glass coloration achieved or determined in the first dyeing process 14 shown. In particular, it is checked whether the determined glass coloration 14 within the tolerance range 12 lies. This is not fulfilled in the case shown. Therefore, it is attempted to at least partially compensate the color deviation by a suitable second dyeing process, at least within the tolerance range 12 to get. This is a Nachfärbemodell for the given target color 10 provided, which starting from the predetermined target color 10 Changes in glass coloration in the particular color space depending on process parameters of the second dyeing process represents.

In the following, a preferred creation of a corresponding, in particular linear, re-inking model is described by way of example. For the modeling, a series of experiments will be created that systematically uses interpolation points for which the effect on ready-colored lenses is determined. For this purpose, a plurality of substantially identical glasses is provided first, which the desired color 10 exhibit. For example, for a target color with a hue "Green50", eight glasses of this color shade are provided. These are measured in particular by means of transmission spectrometry in order to obtain their exact parameters a *, b * and T. These already colored glasses are subjected to a second dyeing process with precisely defined but respectively different process parameters of the second dyeing process, ie in each case preferably two glasses differ in at least one of the process parameters of the second dyeing process. The second dyeing process used is that dyeing process - apart from the precise parameter values - which is also to be used for the glass to be dyed according to the invention. Color 1 Color 2 Color 3 Measurement T Measurement a * Measurement b * 0 0 0 100 0 0 0 100 0 0 0 100 100 100 0 0 100 100 100 0 100 100 100 100 Tab. 1: Experimental plan: For already colored glasses, the following additional color quantity is additionally specified for the subsequent dyeing process.

Table 1 presents a design according to which, in the example described here, the eight glasses are to be subjected to the second dyeing process. The three left columns show some of the selected process parameters of the second dyeing process. In particular, reference quantities of three primary colors are specified here as parameters for the second dyeing process. Thus, for the first glass, the second dyeing process is carried out without color addition, i. H. The glass is subjected to the entire second dyeing process, including, for example, any tempering and / or cleaning steps, without, however, depositing any further color on the glass.

The second glass is subjected to the second dyeing process, whereby the reference amount "100" of a first base color ("Color 1", eg red) is deposited on the glass. For the third and fourth glass, this is done analogously for a second base color ("color 2", eg yellow) or a third base color ("color 3", eg blue). For the fifth to seventh glass combinations of two basic colors are used and for the eighth glass a combination of all three basic colors is used.

Subsequently, the resulting glass color of all eight glasses is determined. In particular, the glasses are measured again spectroscopically in order to determine the resulting color space parameters. From this, the change of the glass color caused by the second dyeing process is determined for each of the plurality of glasses in the determined color space. In particular, the change of the color space parameters is determined as the difference between the corresponding values after and before the second dyeing process. An evaluation preferably takes place via a scheme of statistical experimental design: for example for standard plans, mixing plans, box-and-blind plans or screening plans. reference Color 1 Color 2 Color 3 Color 1 × Color 2 Color 2 × color 3 Color 1 × Color 3 .DELTA.a * 2.62 2.29 -0.47 -0.85 0 0 0 .DELTA.b * 1.24 -0.54 1.71 -0.86 0 0 0 .DELTA.T -3.31 -1.45 -0.06 -0.903 0 0 0 Tab. 2: Model matrix describing the effect of the individual colors and the interactions on the measured quantities a *, b * and T. In this example, the interactions are not taken into account.

Tab. 2 represents an example of the determined changes in the glass coloration for a plurality of glasses caused by the second dyeing process. In particular, determined changes of the color space parameters for the first four glasses are shown, for which the second dyeing process without ("reference") or with the three primary colors ("Color 1", "Color 2", "Color 3") individually. The combinations of several colors are not taken into account in the example of a replenishing model provided here.

und die Farbraum-Parameter als Koeffizienten eines Farbraumvektors

dargestellt werden, welche die Farbänderung im zweiten Färbeprozess bezeichnen. Dabei bezeichnen die einzelnen Komponenten „Farbe 1”, „Farbe 2” und „Farbe 3” des Prozessvektors Farbmengen der Einzelfarben (Grundfarben), während die Komponenten „Farbe 1&2”, „Farbe 2&3” und „Farbe 1&3” vorzugsweise gemäß Tab. 2 Produkte der Farbmengen der Grundfarben bezeichnen. Das lineare Färbemodell wird damit durch die Gleichung Δ(Tab) = M × ΔF bestimmt, wobei die Koeffizienten der Modellmatrix M sich aus dem Versuchsplan ergeben.Thus, the method describes an assignment of reference quantities of the individual colors or color combinations to the changes of the individual color space parameters. This assignment thus provides coefficients of the Nachfärbemodells. In particular, the re-staining model is created as a set of coefficients which defines the changes in the glass coloration as linear combinations of the reference values of the process parameters, that is to say the reference quantities of the primary colors or color combinations. That is, the detected changes in glass color are expressed as linear combinations of the reference values of the process parameters whose coefficients form the coefficient set of the replicate model. In this case, preferably the set of coefficients of the Nachfärbemodells is represented as a model matrix M, while the plurality of process parameters as coefficients of a process vector, in particular a color vector

and the color space parameters as coefficients of a color space vector

which indicate the color change in the second dyeing process. The individual components "color 1", "color 2" and "color 3" of the process vector denote color quantities of the individual colors (primary colors), while the components "color 1 &2","color 2 &3" and "color 1 &3" preferably according to Tab Designate products of the color amounts of the primary colors. The linear coloring model is thus replaced by the equation Δ (Tab) = M × ΔF determined, wherein the coefficients of the model matrix M result from the experimental design.

Preferably, this Nachfärbemodell is now used to determine the required process parameters for a second dyeing process for a variety of glasses to be dyed, the glass coloration after a first dyeing process is not within the tolerance range, the color deviation At least partially compensate and bring the final coloration of the glasses so in the tolerance range.

dargestellt. Auf Basis der bereitgestellten Modellmatrix M, mit den insbesondere wie zuvor beschrieben ermittelten Koeffizienten, werden nun gemäß der Gleichung Δ(Tab)₂ = M × ΔF₂ versucht, die erforderlichen Prozessparameter ΔF₂ derart zu bestimmen, dass die durch das Nachfärbemodell, insbesondere die Modellmatrix M den zu bestimmenden Werten ΔF₂ der Prozessparameter zugeordnete Änderung der Glasfärbung Δ(Tab)₂ eine zumindest teilweise Kompensation der ermittelten Farbabweichung Δ(Tab) darstellt. Dazu werden die Prozessparameter (Koeffizienten) des Prozessvektors ΔF₂ vorzugsweise iterativ variiert. Besonders bevorzugt werden dabei die zumindest die Grundfarbenparameter nacheinander und unabhängig voneinander variiert, um dabei iterativ eine möglichst gute Kompensation der anfänglichen Farbabweichung zu erreichen.So after, for example, the color deviation of the glass with the achieved glass color 14 in 1 was determined, this is in particular as a color deviation vector or color error vector

shown. On the basis of the model matrix M provided, with the coefficients determined in particular as described above, according to the equation Δ (Tab) ₂ = M × ΔF ₂ , it is now attempted to determine the required process parameters ΔF ₂ such that the values determined by the reticle model, in particular the Model matrix M represents the change in the glass coloration Δ (Tab) _{2 associated} with the values ΔF _{2 of} the process parameters to be determined, an at least partial compensation of the determined color deviation Δ (Tab). For this purpose, the process parameters (coefficients) of the process vector ΔF _{2 are} preferably iteratively varied. In this case, the at least the primary color parameters are particularly preferably varied one after the other and independently of each other in order to iteratively achieve the best possible compensation of the initial color deviation.

2 schematically illustrates an application of the Nachfärbemodells in the particular color space. Starting from reached glass coloring 14 after the first dyeing process becomes a color model 16 spanned, which describes the areas that can be reached by the second Nachfärbeprocess. In this color model: the color shift without further color addition ( 16a ), the color shift through the single colors red ( 16b ), Yellow ( 16c ), Blue ( 16d ), the combinations of individual colors ( 16e ) and the interactions of the individual colors with each other ( 16e ).

As in 3 a color deviation vector is shown 16 (Color error vector) determined. This results in particular from the difference between the color location of the achieved glass coloration 14 after the first dyeing process and the specified dyeing 10 , In particular, provided the target color location, so the target color 10 , within the color model 16 the achievable in the second dyeing process glass colorations can be determined from the color deviation vector, which portions of the colors (here red / yellow and blue) are necessary to in a Nachfärbeschritt to the target color 10 to get. The quantities of dye thus determined are adjusted in the subsequent subsequent dyeing process (second dyeing process) and the glasses are subsequently dyed with them.

This procedure is chosen in particular if the color location was outside the tolerances before the subsequent dyeing process and a position of the glass color within the tolerances can be achieved by the subsequent dyeing process.

LIST OF REFERENCE NUMBERS

10

target coloring

12

tolerance

14

reached glass color

16

color model

18

Color deviation vector

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• DIN 6174 [0041]
• DIN 1836 [0041]

Claims (15)

A method of coloring a glass, comprising the steps of: - performing a first dyeing process for the glass; - Determining a color deviation of an achieved glass coloration of a predetermined target color in a given color space; - Providing a Nachfärbemodells for the predetermined target color, which represents, starting from the predetermined target color changes in the glass coloration in the particular color space as a function of process parameters of a second dyeing process; Determining values of the process parameters of the second dyeing process in such a way that the change in the glass coloration associated with the values of the process parameters to be determined, based on the achieved glass coloration, represents an at least partial compensation of the determined color deviation; and - Performing the second dyeing process with the determined values of the process parameters. The method of claim 1, wherein the first and / or second dyeing process comprises a sublimation process, in particular a thermal transfer process, and / or a spray process. A method according to any one of the preceding claims, wherein the process parameters of the second dyeing process comprise a plurality of primary color parameters, each of which defines a color amount of a color from a set of primary colors used in the second dyeing process. The method of claim 3, wherein the process parameters of the second dyeing process comprise a plurality of color combination parameters, each of which at least partially determines a combination of at least two primary colors. Method according to one of the preceding claims, wherein the Nachfärbemodell is provided such that it represents changes in the glass coloration in the particular color space as a linear combination of the process parameters of the second dyeing process. Method according to one of the preceding claims, wherein for determining values of the process parameters of the second dyeing process, the process parameters are varied sequentially such that in each case at least one process parameter of the second dyeing process to improve the at least partial compensation of the determined color deviation is varied, while at least one other process parameter unchanged remains. The method of claim 6, wherein the process parameters of the second dyeing process are successively iteratively varied. Method according to one of the preceding claims, comprising checking whether the determined color deviation lies within a tolerance range, wherein determining values of the process parameters of the second dyeing process and performing the second dyeing process only occur if the determined color deviation is not within the tolerance range. Method according to one of the preceding claims, comprising checking whether the change in the glass coloration associated with the determined values of the process parameters by the replenishing model, based on the glass coloration achieved, leads to a predicted color deviation which lies within a tolerance range, whereby the second dyeing process is only carried out if the predicted color deviation is within the tolerance range. A method of creating a replication model, comprising the steps of: - manufacture a large number of glasses whose coloring corresponds to a common target coloration; Applying a second dyeing process to each of the plurality of glasses, each having a reference value for a plurality of process parameters of the second dyeing process, wherein the glasses differ in pairs in each case in the reference value of at least one process parameter; and Determining a change in the glass coloration caused by the second dyeing process for each of the plurality of glasses in a specific color space. The method of claim 10, wherein applying a second dyeing process comprises: Applying a dyeing process with a first reference amount of a first base color to a first glass; Applying a dyeing process with a second reference amount of a second base color to a second glass; and applying a dyeing process with a third reference amount of a third base color to a third glass. The method of claim 11, wherein applying a second dyeing process further comprises: Applying a dyeing process to the first reference color of the first base color and the second reference amount of the second base color to a fourth glass; Applying a dyeing process with the first reference amount of the first base color and the third reference amount of the third base color to a fifth glass; and Applying a dyeing process to the second reference color of the second base color and the third reference amount of the third base color to a sixth glass. The method of any one of claims 10 to 12, wherein the second dyeing process is for at least one of the plurality of glasses without the addition of color. System for determining process parameters for coloring a glass comprising A color evaluation module for determining a color deviation of a glass coloration achieved in a first dyeing process from a predetermined desired coloration in a specific color space; A data memory for providing a replication model for the predetermined desired color, which, starting from the predefined desired color, represents changes in the glass color in the specific color space as a function of process parameters of a second dyeing process; A parameter evaluation module for determining values of the process parameters of the second dyeing process in such a way that the change in the glass coloration associated with the values of the process parameters to be determined represents an at least partial compensation of the determined color deviation based on the achieved glass coloration; and A data output module for outputting the determined values of the process parameters. A computer program product comprising program code that, when loaded and executed by a computer system, causes it to perform a method of determining process parameters for coloring a glass, comprising the steps of: Determining a color deviation of a glass coloration achieved in a first dyeing process from a predetermined desired coloration in a specific color space; - Providing a Nachfärbemodells for the predetermined target color, which represents, starting from the predetermined target color changes in the glass coloration in the particular color space as a function of process parameters of a second dyeing process; Determining values of the process parameters of the second dyeing process in such a way that the change in the glass coloration associated with the values of the process parameters to be determined, based on the achieved glass coloration, represents an at least partial compensation of the determined color deviation; and - Output of the determined values of the process parameters.

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