DE102021214545B3 - Screen unit and goggle display system for displaying a virtual image with improved efficiency - Google Patents

Abstract

The disclosure relates to a glasses display system (1) for displaying a virtual image in a user's field of vision, with a screen unit (2) for emitting a light (34) as computer-generated image information, the screen unit (2) having at least one first color line and a second color line, each of a different color (14, 11), each having at least one row of color pixels extending along the color line; with a scanning deflection unit (3) for scanning the screen unit (2) and for deflecting the computer-generated image information emitted by the scanned screen unit (2) into an eye of the user; wherein the electro-optical efficiency of the color pixels of the first color line is less than the electro-optical efficiency of the color pixels of the second color line, and the first color line has at least one row of color pixels more than the second color line around the different electro - balance optical efficiency to provide an eyeglass display system (1) having improved efficiency.

Description

The disclosure relates to a glasses display system for displaying a virtual image in a user's field of vision, with a screen unit for emitting light as computer-generated image information, the screen unit having at least a first color line and a second color line, each of a different color each having at least one row of color image points extending along the color line, and with a scanning and deflection unit for scanning the screen unit and for deflecting the computer-generated image information emitted by the scanned screen unit to the user's eyes.

Color line displays are known from the prior art, i.e. color line screen units, which can also be referred to as linear color displays or linear color screen units, which generate a two-dimensional color image using a time-division multiplexing method and a one-dimensional scanning mirror unit in the imaging beam path can. For this, the line screen unit and the scanning mirror unit are controlled in a synchronized manner. For color representation, three basic or primary colors are used, which span a color space. Typically a red, a green, and a blue color.

Particularly advantageous technical implementations use so-called µLEDs. These are advantageous because they can be used to achieve particularly fast switching times of the display pixels, ie the image points in the two-dimensional or three-dimensional color image perceived by the user, and the light intensity is comparatively very high. For multicolored representations, light-emitting diodes with dimensions in the µm range and three different central wavelengths in the blue, green and red range are used in order to achieve a desired color by means of additive color mixing. Line-scanning screen or display technology is particularly useful for use in glasses display systems, so-called head-mounted devices, which are also referred to as virtual reality glasses or augmented reality glasses (VR glasses or AR glasses). become. This results in specific requirements in terms of weight, power consumption and waste heat development of the screen unit. Especially in applications in the field of augmented reality, the maximum achievable brightness is also crucial here, since in this application a virtual image is superimposed on a natural environment and the virtual image in front of sometimes very bright environments can only be seen by the user if the reflected image virtual image is brighter than the light from the natural environment. This is a particularly restrictive boundary condition, especially when the sun is shining brightly, for example when the augmented reality glasses are used outdoors.

The WO 2021/206875 A1 describes a so-called tri-linear display, which enables a two-dimensional image display when viewed via a synchronized scanning mirror. GaN µLEDs are integrated line by line on a CMOS carrier. In addition to three RGB color lines, another color line is also proposed as an option, in particular an implementation with white LEDs as an additional line.

The U.S. 7,771,098 B2 describes a display with four primary color emitters, with an additional yellow color also recommended. The purpose here is to expand the color space and increase the light intensity.

In principle, different methods are known as to how an RGB video signal can be used to control a screen unit or a display with a plurality of primary emitters forming a display pixel, ie more than three RGB emitters. The primary emitters then form corresponding sub-pixels or color pixels, which in turn form the display pixels. For example, in the book "The Multi-Primary Advantage" by Michael E. Miller, in the chapter "Colour in Electronic Display Systems", published by Springer 2019, such a method is presented on pages 183 to 209. There another primary color is used to save energy.

Another problem, namely the correction of chromatic aberrations, is addressed in the paper "Practical Chromatic Apparatus Correction in Virtual Reality Displays Enabled by Cost-Effective Ultra Broad Band Liquid Crystal Polymalenses" by Zhan Tao et al., published in Advanced Optical Materials 8.2 (2020 ): 1901360, treated. There, chromatic aberrations are optically corrected using diffractive liquid crystal lenses. Other approaches to solving this problem are also known, which, however, are extremely disadvantageous due to their technical boundary conditions for spectacle display systems, since they require a large number of optical elements and thus a lot of space and as a result have a high weight and are disadvantageous overall affect the design. Correspondingly, chromatic aberrations are insufficiently compensated in known spectacle display systems, which is reflected in visible artefacts in the form of rainbow-colored edges, particularly in the case of a high-contrast display, for example black text on a white background.

The U.S. 2020/0 183 169 A1 discloses AR glasses having a plurality of tilted pin mirrors embedded between an inner surface and an outer surface of a combiner, the plurality of tilted pin mirrors configured to reflect the guided image light toward the eyebox , and wherein the plurality of pin-mirrors include one or more gaps between them, the one or more gaps permitting passage of ambient light through the combiner toward the eyebox.

DE 10 2021 206 209 B3 discloses an eyeglass display system according to the preamble of claim 1.

The object is therefore to overcome the known problems and to provide a spectacles display system which has improved efficiency, in particular overcoming a number of problems that appear to exist independently of one another in the prior art.

This object is solved by the glasses display system according to the independent patent claim. Advantageous embodiments result from the dependent patent claims, the description and the figures.

One aspect relates to a glasses display system, also called VR glasses or AR glasses, for displaying a virtual image in a user's field of view, preferably in overlay with a real image from a physical environment of the user. The spectacles display system has a screen unit for emitting a light as computer-generated image information. The screen unit has at least a first color line and a second color line and a second color line, each with a different color, with each color line in turn having at least one row of color pixels of the color line extending along the color line, i.e. along a main direction of extension of the color line associated color. The color pixels of a color line, which can also be referred to as sub-pixels corresponding to primary emitters, therefore preferably have a single color, namely the color assigned to the color line. Each color line thus corresponds to a color channel and thus preferably only has primary emitters of the one associated color. The spatial extent of each row corresponds to a spatial extent of the image information in the direction of the row. The spatial extent of the row thus runs perpendicularly to a scanning direction of the scanning deflection unit described further below and thus corresponds to a first dimension of the two-dimensionally represented computer-generated image information. The rows of each color line, and preferably all rows, are parallel. In addition to primary emitter elements, which can be or include respective LEDs, the screen unit can also have one or more lens elements which are designed to direct, in particular to focus, the light generated by the primary emitter elements to the scanning deflection unit mentioned.

The screen unit can consequently also be referred to as a linear screen unit or line screen unit, since it is designed to display only one-dimensional image information at a time. The second dimension required to display the two-dimensional image information is then opened up using the known line-scanning technology.

Correspondingly, the spectacles display system also has a scanning deflection unit, a scanner deflection unit or scanner unit, for scanning the screen unit and for deflecting the computer-generated image information emitted by the scanned screen unit to the eyes of the user, i.e. into at least one eye, i. H. one or both eyes of the user. For this purpose, the scanning deflection unit can have a multiplicity of beam splitter elements, which are designed as scanning beam splitter elements. A suitably designed control unit, which is designed to control the screen unit and scanning deflection unit in a synchronized manner, can thus be used to generate a virtual two-dimensional image using a time-division multiplexing method using the line screen unit. In the time-division multiplexing method, the brightness of the line display unit will be synchronized with a respective scan angle of the scanning deflection unit, as is well known.

In this case, an electro-optical efficiency of the color pixels of the first color line is lower than the electro-optical efficiency of the color pixels of the second color line, and the first color line has at least one row of color pixels more than the second color line in order to to compensate for different electro-optical efficiencies, so that the maximum brightness of the different color lines that can be generated and that can be perceived by a human user and that corresponds to the wavelength-dependent color perception of humans is matched to one another. Consequently, the electro-optical efficiency can also be referred to as the perceived electro-optical efficiency, with the human perception of brightness then being described quantitatively by the V-Lambda curve of DIN 5031, which was in force at the time of filing. This generally defined curve is also referred to as the brightness sensitivity curve or is called and describes the relative spectral brightness sensitivity level the non-linear and wavelength-dependent color perception of humans. The equalization here also includes an incomplete equalization in the sense of equalizing or reducing differences in the maximum brightness of the different color lines that can be generated. The number of rows that the first color line has more than the second color line can correspondingly be the number with the smallest resulting brightness difference at the maximum brightness that can be generated with the two color lines, as perceived by the human user. This brightness can be considered per display pixel, for example.

This has the advantage of compensating for the electro-optical conversion efficiency of semiconductor materials used to manufacture LEDs, which decreases for longer wavelengths. Due to human color perception, at least three primary colors are necessary to create a color space. For a color space that is as large as possible, a red LED with a relatively long wavelength must be used, for example with a wavelength of 640 nm. If only a wavelength of 600 nm, for example, is used instead, the color space is greatly reduced, which means that many red tones are no longer visible show. The lower electro-optical efficiency is thus compensated for in the present case by one or more further rows of color pixels, so that the desired intensities can be achieved in a large color space despite the lower electro-optical efficiency. This is based on the knowledge that with suitable control, the image information of the color pixels scanned one after the other by the scanning deflection unit and thus LEDs are summed up in the user's eye, and thus by scanning or scanning the color pixels arranged at different locations that scanned sequentially than perceived at the same location as the same display pixel. At the same time, the sensitivity of the human eye, which decreases significantly for longer wavelengths in the red range, can be compensated for. Despite the at least one additional row of color pixels, the embodiment described forms the basis for a design of the spectacles display system, which is improved in terms of overall efficiency despite the additional color pixels, as will also be explained with reference to the following statements.

In an advantageous embodiment, it is provided that the color pixels are or include light-emitting diodes which have a light width of less than 50 μm and/or a light area of less than 0.003 mm ² . The luminous width can be understood as a width and/or length of a light-emitting surface of the light-emitting diodes, the luminous surface, or, in the case of round or elliptical luminous surfaces, the corresponding maximum diameter. Such LEDs can be referred to as µLEDs. The light-emitting diodes are preferably based on GaN technology, ie they have gallium nitride as the light-emitting material. The embodiment described is particularly advantageous for light-emitting diodes based on gallium nitride, since the conversion efficiency for longer wavelengths decreases particularly sharply in this semiconductor. With the small size of µLEDs and the particularly fast switching times of GaN primary emitters, line screen units can be implemented in a particularly space-saving and efficient manner.

Non-square color pixels, ie color pixels with non-square luminous areas, ie luminous areas which are round or oval or rectangular with different side lengths, are particularly advantageous here. The color lines with the respective rows can thus be advantageously arranged in a further scanning and overlaying of the multiple rows of one color, so that a two-dimensional virtual image can be generated particularly efficiently.

In a further advantageous embodiment it is provided that the color of the first color line is in the range from 560 to 650 nm, in particular in the range from 570 nm to 590 nm. The color of the first color line or the first color is therefore in the red-orange or else orange area. Since the electro-optical efficiency is particularly low in the red-orange range, it is favorable to provide more rows of color pixels there. Choosing the first color in the orange range, i.e. in the range from 570 to 590 nm, is particularly advantageous, since white tones can be displayed in a particularly energy-efficient way in combination with other colors: With a suitable choice of the second color, i.e. the color of the second color line , for example in the range from 400 nm to 495 nm, preferably in the range from 440 nm to 485 nm, i.e. in the blue range, a large number of white tones can be displayed in this way without the usual and both due to the poor human perception of red color tones as well as due to the poor electro-optical efficiency for the display of inefficient LEDs in the range of 600 nm and more would have to be activated together with another green LED. Not only does one color less have to be generated for the white tone, namely two colors instead of three colors, but moreover the generation of a red light in the range of 600 nm and more can be completely dispensed with and thus the energy efficiency can be significantly increased. Especially for glasses display systems, the resulting higher brightness with less heat is advantageous, and moreover due to the bes Because of its energy efficiency, a smaller battery can be selected for the same operating time, ie a lighter glasses display system can be implemented with the same operating time.

Furthermore, there is also the additional advantage here of improved compensation for wavelength-dependent chromatic aberrations, as explained in more detail below. It should be noted here that the cause of chromatic aberrations is the wavelength dependence of the refractive index when using one or more lens elements to image the line display unit into the human user's field of vision.

As is well known, it is easiest in refractive optics if only one wavelength, for example a spectrally narrow-band laser light, has to be imaged. Due to the color sensitivity of human perception, however, a number of wavelengths or a number of emission spectra are necessary, particularly in the case of spectacle display systems, in order to be able to display a usable color space. Typically, the well-known three emission spectra are used, which, considered individually, have red, green, and blue colors. For example, the wavelengths of the Fraunhofer lines F, d, C (486 nm, 588 nm, 656 nm) are used as standard in optics simulations for the design of optics for the visible range. In the case of an LED display or a µLED display, the wavelength distributions generated by these are known and are used in the optimization of the optics according to the respective emission spectra. The problem is that with three primary emitter elements, a red, a green and a blue primary emitter element, the three emission spectra are comparatively far apart and correction of the chromatic aberration is therefore technically very demanding. Accordingly, the chromatic aberrations are most evident in high-contrast image content, especially black-and-white image content, since all three primary colors are activated equally there.

However, since, according to the approach presented here, black-and-white image content is required only or for the most part, depending on the present design and the desired white tone (which can be one of many white tones with different color temperatures), the color of the first color line and the color of the second color line are required and thus the optics of the glasses display system only have to be optimized for these two central wavelengths or emission spectra in a technical compromise and not for three central wavelengths or emission spectra, an improved effective chromatic correction is technically easy to implement in the approach described here. The configuration described thus enables better chromatic correction of the optics for image content in which chromatic artifacts in the form of rainbow color fringes are particularly visible in conventional approaches. In return, stronger chromatic aberrations for color representations and image content, in which chromatic aberrations can no longer be perceived as strongly by human users, are accepted.

Another advantage here is that the two colors, i.e. the dominant wavelengths used for displaying white, are closer together than in the usual approaches. This also significantly distinguishes the approach described from solutions that propose a white LED as the fourth color. Of course, fewer color pixels have to be activated there for the display of a white color, namely ideally exactly the one additional white LED and none of the other LEDs. However, this is the case because the available white LEDs have a comparatively broad spectral distribution, with dominant wavelengths in the blue spectral range and in the region around 600 nm. Accordingly, the use of a single white LED pixel requires the lens systems required for viewing, such as in the other conventional solutions must be optimized for a large number of wavelengths that are far apart, which, as described, is not necessary with the approach proposed here.

Correspondingly, it is provided that in a CIE 1931 standard color chart color space, a line connecting the colors of the first and second color lines runs essentially parallel to a section of the blackbody curve which covers the blackbody curve from the high-temperature end (T=∞) to at most up to the level of the white point, in particular up to at most the temperature point of 2,700 K, preferably up to at most the temperature point of 1,800 K. The black body curve is also called the black body curve. "Essentially parallel" can be understood here as a tangential course of the connecting line and/or a course in which a maximum distance of the connecting line from the section of the blackbody curve mentioned is a predetermined maximum distance, which for example is 0.05 or 0.01 in the CIE 1931 standard color chart color space does not exceed. The distance between the connecting line and the section of the blackbody curve is measured perpendicular to the connecting line. It is therefore the distance between two points of intersection of a straight line running perpendicularly to the connecting line, with the first point of intersection being the point of intersection with the connecting line and the second point of intersection being the Intersection with the section of the blackbody curve.

In a particularly advantageous embodiment it is provided that the screen unit has exactly two color lines, namely the first and the second color line. A particularly energy-efficient image display system can thus be implemented, which is particularly suitable for displaying black text on a white background or white text on a black background.

In an alternative embodiment to the last embodiment, the screen unit has a third and a fourth color line in addition to the first and the second color line. The color of the third color line is in the green area, i. H. in the range from 500 nm to 550 nm, preferably in the range from 515 nm to 535 nm, and the color of the fourth color line in the red range from 580 nm to 650 nm, preferably in the range from 590 nm to 640 nm. This has the advantage that that the advantages described are achieved in an extended color space of a conventional full-color display and thus a full-color display with improved efficiency is provided.

It can be provided that the electro-optical efficiency of the color dots of the third color line is between the electro-optical efficiency of the color dots of the second color line and the first color line and the third color line has at least one row of color pixels more than the second color line and /or the first color line at least one row of color pixels more than the third color line. Accordingly, it can also be provided that the electro-optical efficiency of the color points of the fourth color line is lower than the electro-optical efficiency of the color points of the first color line and the fourth color line has at least one row of color pixels more than the first color line. This has the advantage that the compensation of the electro-optical efficiency described at the outset is further improved and is also achieved for the other colors.

In a further advantageous embodiment it is provided that the colored lines, in particular each of the colored lines, have at least two, preferably at least three rows of points of the respective color of the colored line. This has the advantage that fluctuations in the brightness between the color pixels scanned one after the other in time can be compensated for, since the scanning deflection results in a chronological averaging over the different rows. As a result, stripe-like artefacts, such as those that often occur when the brightness of the μLEDs is not quite precisely controlled, are avoided.

In a further advantageous embodiment, it is provided that each color line has a reserve row of color pixels, and the screen unit is designed to control corresponding color pixels of the reserve row instead of respective color pixels categorized as non-functional in the at least one regular row described above , i.e. to activate or deactivate, whereby the two color pixels in the associated row each have the same position. The color pixel in the reserve row thus replaces a color pixel in one of the other rows if it fails. The categorization as non-functional can take place during a manufacturing process, which then reduces rejects of the goods, or it can also be determined after commissioning as part of a calibration process. In both cases, the sustainability and thus the efficiency of the glasses display system is promoted.

A further aspect relates to a screen unit for one of the described embodiments of the glasses display system. Advantages and advantageous embodiments of the screen unit correspond to the features of the described embodiments of the spectacles display system and their advantages relating to the screen unit.

The features and feature combinations mentioned above in the description, also in the introductory part, as well as the features and feature combinations mentioned below in the description of the figures and/or shown alone in the figures, can be used not only in the combination specified in each case, but also in other combinations, without departing from the scope of the invention. The invention is therefore also to be considered to include and disclose embodiments that are not explicitly shown and explained in the figures, but that result from the explained embodiments and can be generated by separate combinations of features. Versions and combinations of features are also to be regarded as disclosed which therefore do not have all the features of an originally formulated independent claim. Furthermore, embodiments and combinations of features, in particular through the embodiments presented above, are to be regarded as disclosed which go beyond or deviate from the combinations of features presented in the back references of the claims.

Further advantageous embodiments are shown on the basis of the following figures, which explain the subject according to the invention in more detail without wishing to restrict it to the specific embodiments shown here.

• 1 einen CIE-1931-Farbraum, anhand dessen eine beispielhafte erste Ausführungsform einer Bildschirmeinheit für ein Brillen-Anzeige-System erläutert wird;
• 2 einen weiteren CIE-1931-Farbraum, anhand dessen eine alternative Ausführungsform einer Bildschirmeinheit für das Brillen-Anzeige-System erläutert wird;
• 3 ein beispielhaftes Brillen-Anzeige-System mit einer Bildschirmeinheit wie sie anhand von 1 oder 2 beschrieben wurde; und
• 4a bis 4c eine beispielhafte Ausführungsform einer Bildschirmeinheit.

show:

• 1 a CIE 1931 color space, on the basis of which an exemplary first embodiment of a display unit for a spectacle display system is explained;
• 2 another CIE 1931 color space, which is used to explain an alternative embodiment of a display unit for the eyeglass display system;
• 3 an exemplary glasses display system with a screen unit as based on 1 or 2 has been described; and
• 4a until 4c an exemplary embodiment of a display unit.

In the figures, functionally identical or identical elements are provided with the same reference symbols.

1 shows a CIE 1931 color space 10 with coordinates x and y. In this, a sub-color space 16 is spanned by four primary colors 11, 12, 13 and 14. The color space 10 is limited by the boundary line 101, which is given by monochromatic emission spectra. In the example shown, the primary color 11, which can be referred to as the second color, is a blue spectrum with a central wavelength of 475 nm here. In the present case, primary color 12 is a green spectrum with an exemplary central wavelength of 525 nm. Primary color 12 can be referred to as the third color. In the present case, primary color 13 is a red spectrum with an exemplary central wavelength of 640 nm. This color can be referred to as the fourth color. In the present case, primary color 14 is an orange spectrum with an exemplary central wavelength of 580 nm. Primary color 14 can be referred to as the first color. The four colors subdivide the partial color space 16 into two sub-color spaces 161 and 162. In the sub-color space 161, a significantly higher electro-optical efficiency can be achieved than in the sub-color space 162, since colors are only defined there with the first, second and third Color 14, 11, 12 can be generated, whereas in the sub-sub-color space 162 colors with the first, second and fourth color 14, 11, 13 are generated. This is due to the fact that an emitter element assigned to the fourth color 13, for example a corresponding μLED, does not have to be activated for colors in the first sub-color space 161. Due to the longer wavelength, in the present case this has a significantly poorer electro-optical efficiency than an emitter element assigned to the first color 14 .

A row of white-color points 15, the so-called CIE standard illuminations, which lie on the black-body curve 17, is also drawn in. The CIE standard illuminations E, D50, D55, D65, D75 and D93 are shown here. The white point 15W with the associated RGB video signal R=G=B is calibrated to one of the CIE standard illuminance white color points 15 or a similar white color point depending on the respective application scenario and is the only point 15, 15W that is not on the blackbody curve 17. In the present case, the extended color space 16 is used through the use of more than three different primary colors, with the sub-color space 16 being in turn subdivided into sub-color spaces 161, 162, with an electro-optically more efficient sub -partial color space 161 and an electro-optically inefficient sub-color space 162. It is particularly advantageous here that the more efficient color space 161 contains the white color points 15, in particular the white point 15W. As a result, the white tones corresponding to the white color points 15 or the white point 15W can be represented particularly energy-efficiently.

In a particularly advantageous embodiment, a line 18 which separates the sub-color spaces 161 and 162, the connecting line 18 which connects first color 14 and second color 11, lies close to the white color points 15 or the white point 15W , in particular the white color points 15, which are particularly relevant for the respective application scenario. Since the white-color points 15 are arranged on the black-body curve 17 according to their associated color temperature, this advantageous embodiment corresponds to a substantially parallel course of the connecting line 18 with a high-temperature section of the black-body curve 17, which extends from the high-temperature end of the Black body curve 17 up to a white point 15, for example in the white point 15 corresponding to standard illumination D50, to which a temperature of approximately 5,000 K on the black body curve 17 can be assigned.

Thus, in order to generate white light, almost only or only the first color 14 and the second color 11 must be generated with high intensity, ie only the color pixels of two different colors must be activated. As a result, when displaying white text on a black background or conversely, black text on a white background, only two emission spectra are dominant in the light. This is advantageous for a chromatic correction of the optics, since only two essential wavelengths or wavelength ranges have to be corrected and not, as is otherwise usual, three wavelengths or wavelength ranges. In addition, the two wavelengths of color 11 and color 14 are particularly close together, differing by only 105 nm in the example shown On the other hand, the optics in the example shown have to be corrected for the wavelengths of 475 nm, 525 nm and 640 nm, i.e. over a wavelength range of 180 nm instead of 105 nm. The first orange color thus becomes a technically simple correction of chromatic aberrations for the relevant case of the display of black-and-white writing and, at the same time, because GaN (µ)LEDs have a sharply decreasing electro-optical efficiency for longer wavelengths, the electro-optical efficiency in the glasses display systems used is also increased.

In 2 an exemplary embodiment with exactly two colors 14, 11 is shown. A corresponding spectacle display system thus enables black-and-white representations as well as color representations of fewer colors that lie on the connecting line 18 . Correspondingly, in this case, lens elements which are part of the associated screen unit only have to be chromatically optimized for the two colors 14, 11. Ideally, the color pixels that produce the two colors 14, 11 then have a spectrally narrow spectrum, for example by being implemented as μLED GaN technology. Ideally, the respective emitters are chosen in such a way that the connecting line 18 runs essentially parallel to a high-temperature section of the blackbody curve 17 . For example, the connecting line 18 can come closest to the blackbody curve 17 or even touch or intersect it at the point which corresponds to the white point 15 desired for the respective application scenario. This means that a distance between the connecting line 18 and the black-body curve 17 is minimal for the point on the black-body curve which corresponds to the preferably desired white point 15 . In practice, this means that small deviations between the desired white point and the white tone that can be achieved with the two colors can be tolerated. Accordingly, no standard white light can then be reduced, and a black-and-white image generated with such a screen unit has a color cast. The greater the deviation here, the greater the color cast, so that the maximum permitted deviation for the respective usage scenario of the screen unit has to be specified specifically.

In the example shown, several points T∞, T ₅₅₀₀ , T ₃₀₀₀ , T ₂₅₀₀ are entered on the black body curve 17 , which correspond to a respective temperature of ∞, 5500 K, 3000 K and 2500 K. The distance of the connecting line 18 from the respective points T∞, T ₅₅₀₀ , T ₃₀₀₀ , T ₂₅₀₀ , i.e. the distances d∞, d ₅₅₀₀ , d ₃₀₀₀ , d ₂₅₀₀ result from the length of a normal on the connecting line 18 through the respective Points T∞, T ₅₅₀₀ , T ₃₀₀₀ , T ₂₅₀₀ . Depending on the application scenario, the colors 14, 11 and thus the course of the connecting line 18 can be selected in such a way that the maximum distance of a desired section, for example a high-temperature section of the blackbody curve 17, which runs from the point T∞ to the point of a specified temperature , for example T ₂₅₀₀ ranges, reaches a maximum of a predetermined value. The connecting line 18 can also intersect the black-body curve 17 once or twice. The connecting line 18 can also be placed in such a way that, for example, a squared deviation from the connecting line 18 to the desired section of the blackbody curve 17 is minimized, thus, for example, a squared error is minimized.

In 3 An exemplary spectacles display system 1 is shown with a line screen unit 2 for emitting a light 34 as computer-generated image information, and with a scanning and deflection unit 3 for scanning the screen unit 2 and for deflecting the light 34 emitted by the scanned screen unit 2 into a User's eye 392 shown.

The screen unit 2 has a display element 30 and a lens element 31 which is arranged in an optical path between the display element 30 and the scanning deflection unit 3 . The scanning deflection unit 3 has a row of scanning, partially transparent mirror elements 32 which are arranged one above the other in a z-direction. At a given point in time, the light 34, which has an intensity distribution predetermined by the screen element 30 in the y-direction, is deflected at each beam splitter 32 to the eye 392. Only part of the light 34 strikes the pupil 391 of the eye 302 and is therefore perceived.

In the present case, the beam splitter elements 32 are designed as scanning beam splitter elements 32 and correspondingly have an axis of rotation 33 running parallel to the y-axis with a maximum deflection 323 and 322 and a nominal deflection 321 . Correspondingly, the light 34 can be guided to the eye 392 at all scan angles 341 lying between the maximum deflection 323 and 322 corresponding to the assigned maximum angles 343, 342. A virtual two-dimensional image can thus be generated for a linear screen element 30 by means of a time-division multiplexing method. As is known, the linear screen element 30 is controlled in terms of its brightness synchronously with the respective scan angle 341 . The main extension direction of the line screen element 30 runs parallel to the y-axis into the plane of the drawing. This is then also the direction of the associated color lines, as described below.

In 4 Various views of an exemplary linear or line-shaped screen element 30 are shown. A multiplicity of LEDs, here μLEDs, are arranged in respective color lines 411, 412, 413 and 414 on a carrier 45, for example a silicon substrate with integrated circuit electronics. Each color line 411, 412, 413, 414 includes respective rows 411a, 412a, 412b, 413a, 413b, 413c, 414a, 414b, . . . 414g of color pixels 401. The number of rows is chosen as an example. Each color line 411, 412, 413,414 corresponds to a color 11, 12, 13, 14. For example, color line 414 can correspond to the first color 14, color line 411 to the second color 11, color line 412 to the third color 12, and color line 414 to the fourth Color 13. This creates a four-color line display.

Each group can optionally contain a spare row 411', 412', 413', 414' of spare color pixels 402. If a defective color pixel 403 is found in a color line, for example the color line 414, and is consequently categorized as non-functional, an assigned reserve color pixel 404 can be used in its place by means of software. The two color pixels 403, 404 in the respective row, here row 414, are arranged at the same position in the x-direction and thus in the scanning direction 46, ie in the same column. Since the screen element is scanned in the scanning direction 46 perpendicular to the y-direction, these spare color pixels 402 can be arranged at a distance from the regular rows 411a, 412a, 412b, 413a to 413c, 414a to 414g. Advantageously, the rows 411a, 411', 412a, 412b, 412', 413a to 413c, 413', 414a to 414g, 414' of a color line each have the same x-pitch distance 426 in the scanning direction 46, and the color -pixels 401 of a row in the y-direction have a uniform y-pitch distance 421. The y-pitch distance 421 perpendicular to the scanning direction is ideally identical to the x-pitch distance 426 in the scanning direction. By using an anamorphic lens element 31, this can in principle also be technically implemented with different distances. In principle, the color pixels 402 or their luminous areas can have any shape, for example round, square or rectangular. However, a rectangular design is particularly advantageous, since in combination with µ-lenses 47, as shown in 4b and 4c are shown as part of the lens element 31, different angular distributions 481 and 482 can be set in the main extension plane of the screen element 30, which correspond to the geometric dimensions 422 and 423 of the luminous surfaces in the x and y directions.

The distance between the color lines 411, 412, 413, 414, 424 should preferably be selected as a multiple of the x-pitch distance 426, since the brightness information must be forwarded synchronously with the scanning beam splitter element 32 in the scanning direction 46 from row to row. Per color line 411 to 414, i. H. For each color 11 to 14, the number of rows in the scanning direction 46 can be freely selected in order to compensate for any perceived differences in brightness caused by multiple exposure. For this purpose, the brightness information of each color pixel 401, designed here as a μLED, of a line is also shifted by one line after scanning to the next line and displayed again. As a result, the brightness adds up for the eye 392 .

Claims (13)

Spectacles display system (1) for displaying a virtual image in a user's field of vision, with - a screen unit (2) for emitting a light (34) as computer-generated image information, the screen unit (2) having at least a first color line and a second color line, each of a different color (14, 11), each having at least one row of color pixels extending along the color line; - A scanning deflection unit (3) for scanning the screen unit (2) and for deflecting the scanned screen unit (2) from the computer-generated image information emitted into an eye of the user; wherein the electro-optical efficiency of the color pixels of the first color line is less than the electro-optical efficiency of the color pixels of the second color line, and the first color line has at least one row of color pixels more than the second color line around the different electro - to balance optical efficiency, characterized in that in a CIE 1931 standard color chart color space (10) a connecting line (18) of the colors (14, 11) of the first and second color line is essentially parallel to a section of the blackbody curve (17th ) which includes the black body curve (17) from the high temperature end (T∞) to at most the height of the white point (15W). Glasses display system (1) after claim 1 , characterized in that the color pixels are or include light-emitting diodes which have a light width of less than 50 µm and/or a light area of less than 0.003 mm ² and are based in particular on GaN technology. Spectacles display system (1) according to one of the preceding claims, characterized draws that the color pixels are rectangular with different side lengths. Spectacles display system (1) according to one of the preceding claims, characterized in that the color (14) of the first color line is in the range from 560 nm to 650 nm, in particular in the range from 570 nm to 590 nm. Spectacles display system (1) according to the preceding claim, characterized in that the color (11) of the second color line is in the range from 400 nm to 490 nm, in particular in the range from 440 nm to 480 nm. Spectacle display system (1) according to one of the preceding claims, characterized in that the section of the blackbody curve (17) comprises the blackbody curve (17) from the high-temperature end (T∞) to at most the temperature point (T ₂₇₀₀ ) of 2700K, preferably up to the temperature point (T ₁₈₀₀ ) of 1800K. Spectacles display system (1) according to one of the preceding claims, characterized in that the screen unit (2) has exactly two color lines. Glasses display system (1) according to one of Claims 1 until 6 , characterized in that the screen unit (2) has a third and a fourth color line in addition to the first and the second color line, the color (12) of the third color line being in the range of 500 nm to 550 nm, in particular in the range of 515 nm to 535 nm, and the color (13) of the fourth color line in the range from 580 nm to 650 nm, in particular in the range from 590 nm to 640 nm. Spectacles display system (1) according to the preceding claim, characterized in that the electro-optical efficiency of the color points of the third color line is between the electro-optical efficiency of the color points of the second color line and the first color line and the third color line at least one row of color pixels more than the second color line and the first color line has at least one row of color pixels more than the third color line. Spectacles display system (1) according to one of the two preceding claims, characterized in that the electro-optical efficiency of the color points of the fourth color line is lower than the electro-optical efficiency of the color points of the first color line and the fourth color line has at least one row of has more color pixels than the first color line. Spectacles display system (1) according to one of the preceding claims, characterized in that the color lines have at least two, preferably at least three rows of color pixels of the respective color of the color line. Spectacles display system (1) according to one of the preceding claims, characterized in that each color line has a reserve row of color pixels, and the screen unit (2) is designed, instead of respective color pixels categorized as non-functional, of the at least to control color pixels of the reserve row corresponding to a regular row, the two color pixels in the associated row each having the same position. Screen unit (2) for a spectacles display system (1) according to one of the preceding claims.

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