Projection device and method for illuminating a plurality of virtual pixels

Abstract

The present invention relates to a projection device (1) for illuminating a plurality of virtual pixels (2), wherein the virtual pixels generate a first individual image during a first time window. The projection device (1) includes a laser device (4) having a plurality of laser sources (5a, 5b, 5c) designed to emit lasers (L1, L2, L3) having substantially the same wavelength through a plurality of emission points arranged at relatively defined intervals. The projection device (1) also includes a deflection module (6) designed to sequentially deflect the lasers (L1, L2, L3) generated by the laser sources (5a, 5b, 5c) onto the plurality of virtual pixels (2), and to deflect the laser (L1) of the first laser source (5a) onto the first pixel (2a) and the laser (L2) of the second laser source (5b) onto the second pixel (2b) within a first sub-time window during the first time window. The projection device (1) also includes a control element designed to manipulate a plurality of laser light sources (5a, 5b, 5c) and / or a deflection module (6) such that the third pixel (2c) is illuminated by the laser (L2) of the second laser light source (5b) in a second sub-time window during a first time window, and the third pixel (2c) is illuminated by the laser (L1) of the first laser light source (5s) in a subsequent third sub-time window.

Description

[0001] This application claims priority to German patent application 10 2023 133 019.5, dated November 27, 2023, the disclosure of which is incorporated herein by reference. Technical Field

[0002] The present invention relates to a projection apparatus for illuminating a plurality of virtual pixels, wherein the plurality of virtual pixels generate a first individual image during a first time window, and also to a method for illuminating the plurality of virtual pixels. Background Technology

[0003] LBS (Laser Beam Scanning) devices for NTE (Near-Eye) glasses (also known as data glasses) are becoming increasingly popular and are continuing to be developed. Compared to LCoS (Liquid Crystal Coated Silicon) LED (Light Emitting Diode) systems and DLP (Digital Light Processing) LED systems, LBS systems have the following advantages: In short, only the pixels of a single image (frame) contribute to energy consumption, and pixels are illuminated for the time required to display a single image. Although this design has some drawbacks, such as the laser source consuming energy even when not emitting light, LBS systems still consume less energy compared to LCoS and DLP LED systems, where the entire image surface must be continuously illuminated to display a single image.

[0004] Furthermore, the luminous density offered by the laser light source in an LBS system is a significant advantage over that of an LED system. By adapting the supply current applied to the laser light source and / or by adapting the illumination time of the pixels, the luminous density of the pixels (relative to LED systems) can be increased almost without limitation without increasing the optical interface. In addition, the brightness dynamics of the laser light source are higher than those of LEDs or OLEDs (organic light-emitting diodes).

[0005] However, to achieve high image resolution and brightness, LBS systems heavily rely on the interaction between laser power and deflection modules used to scan individual image pixels. The current limiting factor is the frequency of the deflection modules, such as the frequency of mirrors in a MEMS (Micro-Electro-Mechanical Systems) system, which enables the scanning and illumination of each individual pixel of the image.

[0006] Furthermore, it has been found that although LBS systems have already achieved energy savings compared to other known systems, especially in the field of compact data glasses, there is still a need to pursue further reductions in energy consumption because the available space for batteries to provide power is very limited.

[0007] Therefore, in summary, there is a need to provide a system, particularly a system for projecting at least one individual image, which is compactly constructed, provides high image brightness, provides a high dynamic range of image brightness, provides high image resolution, and at the same time has the lowest possible energy consumption. Summary of the Invention

[0008] This need is achieved through the subject matter of the independent patent claims. Improved forms and design forms of the proposed principle are given in the dependent claims.

[0009] In known LBS systems, each individual laser source must cover the entire dynamic brightness range to map different brightness levels by means of the laser source illuminating the pixels. This typically results in low wall-plug efficiency (WPE) when low brightness is needed and insufficient optical power when high brightness is required. Furthermore, the power consumption in standby mode is very high in such laser sources. This means that when scanning pixels, if laser emission should be suppressed to inhibit pixel illumination, the laser source operates slightly below the laser threshold, but should achieve rapid startup to illuminate subsequent pixels. In short, here, the higher the laser threshold, the higher the maximum optical power of the laser source.

[0010] The inventors now propose a projection device and a method for operating such a projection device, wherein the projection device provides improved brightness and an increased range of accessible brightness through a combination of multiple features, and thereby has reduced current consumption.

[0011] This projection device, specifically an LBS system, utilizes multiple laser light sources combined with a deflection module for each wavelength or color of light. The deflection module is designed to simultaneously illuminate multiple virtual pixels of a single image on the projection surface using the light from the multiple laser light sources. This allows for improved resolution of the individual image at a preset grating frequency of the deflection module. Furthermore, the inventors propose that, compared to known systems, using a smaller laser light source or one with a shorter laser ridge sacrifices optical power but benefits from the lower threshold current required in the LBS system, resulting in lower average current consumption. This is because the current required to operate the laser light source, slightly below the laser threshold, is significantly reduced, and the laser light source consumes significantly less energy in its so-called standby mode. Now, to further enhance the image brightness reduced due to the lower optical power, the inventors propose illuminating the virtual pixels requiring increased brightness multiple times within a single image, thus giving the human eye the corresponding impression of higher overall pixel brightness. Although this causes a partial reduction in the previously achieved resolution improvement at a given scan frequency of the deflection module, it is possible to determine whether a higher image brightness with reduced resolution or a lower image brightness with increased resolution is desired.

[0012] Accordingly, the core of the projection device according to the invention lies in using a painting scheme in which the virtual pixels of a single image can be illuminated multiple times during the duration for displaying a single image. Theoretically, this could also be achieved through a higher scanning frequency of the deflection module, but since the scanning frequency of the deflection module, as known at the current point in time, is a limiting factor in LBS systems, multiple illuminations of virtual pixels within a single image require a correspondingly constructed deflection module combined with more than one laser light source per wavelength or color.

[0013] Using this projection device, at least some of the following advantages can be achieved: • Compact shape factor (e.g., < 0.7 mm³); • High image brightness and high dynamic range (e.g., indoor night mode = 300 nt-500 nt, outdoor beach mode = 10000 nt), where 1 nt = 1 cd / m²; • Low energy consumption (e.g., 100 mW / user's eye); • High or appropriately high image resolution; • The display of individual images is independent of the distance between the projection device and the projection surface, which also enables the illumination of non-planar projection surfaces (the eye).

[0014] Furthermore, it is feasible to enable situational responses based on different frame conditions using the projection device according to the invention. For example, the projection device can permanently switch between different operating types and / or generate mixed operating types so that the projected image mode is optimally adapted to the current situation. Possible modes include, for example: (1) High-resolution mode Here, for example, all laser light sources operate in parallel to display individual images with as many illuminated virtual pixels as possible. In this mode, the number of illuminated pixels per individual image is maximized (resolution), while the brightness of each illuminated virtual pixel in the individual image is reduced.

[0015] (2) High brightness mode

[0016] Here, for example, all laser sources operate in parallel to illuminate a smaller number of virtual pixels of a single image multiple times during the duration of displaying a single image, i.e., to produce a single image with reduced resolution but increased perceived brightness for this purpose. In this mode, the image resolution (illuminated pixels or single image) is reduced, while the absolute brightness of the single image is increased and / or a high dynamic range of brightness is achieved.

[0017] (3) Low brightness mode

[0018] Low-brightness mode can be implemented at different resolutions as required. In low-brightness mode, the laser source can operate with low current, or illuminate virtual pixels, specifically avoiding multiple illuminations for each individual image. This mode is relatively efficient and energy-saving thanks to a relatively small laser source.

[0019] (4) Dynamic image resolution

[0020] Here, the image resolution of each individual image can be adapted to the context. For example, if the projection device includes eye tracking for the user, it is feasible to support foveated rendering, which can further reduce the overall power consumption of the projection device. Foveated rendering is particularly a rendering technique in which an eye tracker integrated into virtual reality glasses is used to reduce rendering costs by significantly reducing the image quality or resolution of the peripheral visual field (outside the macula).

[0021] (5) Dynamic brightness adjustment

[0022] Here, the brightness of each individual image can be adapted to the context. The overlay of augmented reality (AR) with the real world within an AR environment requires a high dynamic range of brightness to avoid glare on the one hand, and to ensure the AR information is visible even on bright surfaces on the other. Accordingly, it would be feasible to adapt the brightness of individual images or consecutive individual images to the contextual brightness of the environment.

[0023] According to a first aspect, a projection device is provided for illuminating a plurality of virtual pixels. The plurality of illuminated pixels generate a first individual image during a first time window.

[0024] Here, the number of illuminated virtual pixels used to display or derive a single image, along with the size of the displayed single image, constitutes a measure of image resolution (or simply resolution). A single image displayed with more illuminated virtual pixels has a higher resolution than a single image of the same size displayed with fewer illuminated virtual pixels. Therefore, to achieve higher resolution, a single image must be displayed with a larger number of illuminated pixels, or with a larger number of illuminated pixels while keeping the size of the single image constant.

[0025] Here, the term "single image" (frame) should be understood as an image displayed within a defined time period to present a single image. This time period, also referred to below as a time window, is the period during which a single image is displayed or produced. In the fields of film and video technology, where multiple single images are displayed sequentially to display moving images, the time period used to display a single image is derived from the image frequency (more precisely, the image switching frequency) or frame rate. Here, image frequency specifically refers to the number of single images recorded or played per time slice, usually expressed in fps (frames per second), less commonly in BpS (frames or images per second) or Hz (hertz). The human eye perceives continuous images as a moving (but not necessarily jitter-free) scene at approximately 14 to 16 frames per second (individual variation). However, current image switching frequencies are 24 Hz (in the case of many films), 48 Hz (in the case of well-made new films and 3D films), 25i / 30i Hz (in the case of television), and 60 Hz–390 Hz (in the case of computer games).

[0026] To display individual images, the projection device includes a laser unit with multiple laser light sources designed to emit laser light of substantially the same wavelength. Each laser light source is associated with an emission window or emission point, through which the laser light emits laser light from the laser unit. The emission points are arranged at relatively defined intervals.

[0027] Specifically, the laser device can be a multi-channel laser (also known as a multi-ridge laser), which comprises multiple laser ridges constructed on a common semiconductor substrate. The laser source or its emission window can be arranged at a relatively defined spacing, particularly less than 30 µm or less than 10 µm. To reduce current consumption, it can particularly be a relatively small laser source, especially one with a reduced laser ridge length.

[0028] Here, the laser ridges can be arranged in parallel and / or stacked on the semiconductor substrate. However, it is also possible for the laser source to consist of individual laser sources, arranged side-by-side or stacked. Furthermore, combinations of the aforementioned embodiments are also possible.

[0029] However, the laser device can also be a photonic integrated circuit (PIC), which couples multiple laser sources. Here, the emission points are combined into small, mutually defined intervals within the waveguide of the PIC, allowing the emission points to be arranged, for example, spaced 3 µm to 5 µm apart. This design has the advantage that the laser sources themselves can be spaced further apart, allowing for better individual heat dissipation during operation. Furthermore, electro-optical interactions between adjacent laser sources can be better reduced.

[0030] To illuminate individual images or their virtual pixels not only with light of a single wavelength or color, a projection device can include multiple laser devices, each with a laser source designed to emit light of a different wavelength or color. For example, a projection device can include three laser devices, where the first laser source is designed to emit red light, the second to emit green light, and the third to emit blue light. This results in a so-called RGB (red, green, blue) projection device, with which the virtual pixels of an individual image can be illuminated separately with red, green, and blue light, and any other desired color can be mixed from these colors.

[0031] Furthermore, the projection device includes a deflection module designed to sequentially deflect laser light generated by a laser source onto a plurality of pixels to be illuminated. The deflection module is specifically designed to sequentially (e.g., row by row, column by column) deflect the light from the laser source onto virtual pixels of a single image on the projection surface to be illuminated. For this purpose, the deflection module can, for example, be movably designed to sequentially deflect the light from the laser source onto the virtual pixels of a single image on the projection surface at periodic intervals, for example, within a time window used to display a single image. This periodic deflection of the laser source light onto virtual pixels of a single image on the projection surface can also be specifically referred to as scanning pixels or drawing pixels.

[0032] For example, a deflection module can be designed to scan a certain number of locations (also called theoretical pixels) at a defined frequency, for example, on a projection surface or projection plane. The locations or theoretical pixels can be arranged in columns and rows, and are equidistant from each other, particularly in the horizontal and vertical directions. The number of locations or theoretical pixels can be determined specifically by the maximum size of the image to be displayed, the maximum possible scanning frequency of the deflection module, the length of the time window used to display individual images, and optionally by the number of locations or theoretical pixels that the deflection module can simultaneously illuminate for each scanned location. Accordingly, the theoretical pixel spacing scanned by the deflection module per time window can be obtained.

[0033] It's worth mentioning in this regard that the number of illuminated pixels in a single image may deviate from the theoretical number of pixels. However, it's also possible that the number of illuminated pixels in a single image is the same as the theoretical number. In this case, illuminating all theoretical pixels yields a single image with the maximum possible resolution, while illuminating only a portion of all theoretical pixels yields a single image with reduced resolution.

[0034] Here, the time used for scanning pixels can be derived, for example, from the time window used to display a single image and the theoretical number of pixels, and can be specifically referred to as a sub-time window below. For example, the time used for scanning pixels, i.e., the sub-time window, can be derived by dividing the time window used to display a single image by the theoretical number of pixels. Accordingly, the time used for scanning pixels (i.e., the sub-time window) can also be derived from the time window used to display a single image and the number of scan positions of the deflection module, wherein the number of scan positions can deviate from the number of virtual pixels to be illuminated. For example, the time used for scanning pixels (i.e., the sub-time window) can be derived by dividing the time window used to display a single image by the number of scan positions of the deflection module. The time period of the sub-time window is specifically a true sub-interval of the time window, and is correspondingly shorter than the time period of the time window.

[0035] For example, the deflection module can include movable parts and is formed, for example, by one or more MEMS mirrors that deflect light from the laser source onto virtual pixels of a separate image on the projection surface to be illuminated. For example, the deflection module can be formed by at least two mirrors (especially MEMS mirrors) arranged in series, each mirror moving or oscillating about an axis. Here, the mirrors can oscillate about two substantially perpendicular axes, such that one mirror scans, for example, columns of a theoretical pixel array sequentially, and the other mirror scans rows of the theoretical pixel array at a slower frequency. However, it is also possible to proceed in the reverse order. However, the deflection module can also be formed by one or more mirrors that oscillate simultaneously about two substantially perpendicular axes. Preferably, the mirrors oscillate about the two axes at a natural frequency (i.e., low energy requirement) so that the mirrors scan a pattern, particularly a so-called Lissajous figure, that deviates from the pixel spacing of a Cartesian arrangement. In both cases, the virtual pixel is illuminated only when the geometry of the laser source and mirror positions allows. Since the individual emission points of the laser device are arranged spatially separate from each other, the possibility of illuminating the virtual pixel with light from different laser sources is obtained. In this way, multiple laser light sources can be superimposed to illuminate a virtual pixel.

[0036] However, it is also possible that the deflection module is formed by or includes one or more facets. These facets can rotate about two substantially perpendicular axes, such that one facet scans, for example, the columns of a theoretical pixel array sequentially, while the other scans the rows of the theoretical pixel array at a slower frequency. The reverse order is also possible. It is also possible that the deflection module includes non-moving parts and still provides the desired functionality. For example, the deflection module can include one or more so-called optical phased arrays (OPAs). Phased array optics is a technique for controlling the phase and amplitude of light waves emitted or reflected from a two-dimensional surface by means of adjustable surface elements. By dynamically controlling the optical properties of the surface at a microscopic level, the direction of the beam can be deflected without moving parts. Here, diffractive optical elements, such as dynamic virtual lenses, can be fabricated, which are used not only for orientation but also for beam focusing or splitting. Real-time holograms can also be generated through dynamic phase changes. With such a deflection module, light from a laser source can be deflected in a desired manner to the virtual pixels of a single image to be illuminated on the projection surface.

[0037] According to the present invention, the deflection module is designed to simultaneously deflect the laser light from a first laser source onto a first pixel and the laser light from a second laser source onto a second pixel within a first sub-time window during a first time window, particularly during the scanning position of the movable deflection module. Therefore, multiple virtual pixels can be illuminated simultaneously within a sub-time window.

[0038] The deflection module, in the case of a single component or interconnected components, is designed to simultaneously deflect light from, for example, two adjacent emission points, and thus the light from two laser sources, onto two different pixels at a given scanning position. At a subsequent scanning position (e.g., after the deflection module has moved), the deflection module can thus simultaneously deflect the light from the adjacent laser sources onto two other pixels. Alternatively, the deflection module can be designed as multiple separate components, where at a given scanning position, a first element of the deflection module deflects the light from a first laser source onto a first pixel, and simultaneously a second element of the deflection module deflects the light from a second laser source onto a second pixel. At a subsequent scanning position, after movement, the elements of the deflection module can deflect the light from both laser sources onto two other pixels.

[0039] Furthermore, the projection device includes a control element designed to manipulate multiple laser light sources and / or a deflection module, such that during a first time window, a third pixel is illuminated using the laser light from a second laser light source in a second sub-time window, and subsequently, during a third sub-time window, the third pixel is illuminated using the laser light from a first laser light source. Therefore, during a time window used to display a single image, one or more virtual pixels to be illuminated can be sequentially illuminated using the light from multiple laser light sources. This increases the perceived brightness of the illuminated pixels. However, at a preset scanning frequency of the deflection module, this results in the inability to illuminate all theoretical pixels, thus requiring at least a partial reduction in the resolution of the single image due to the simultaneous illumination of multiple pixels. However, it is possible to determine, depending on the context, whether a higher image brightness with reduced resolution or a lower image brightness with increased resolution is desired.

[0040] In the context of this specification, "first" and "second," such as "first" sub-time window and "second" sub-time window, or "first" laser source and "second" laser source, specifically refer to two distinct regions, elements, time periods, or objects.

[0041] Projection devices can be specifically designed to illuminate virtual pixels on a projection surface or projection plane. A projection surface can be specifically understood as the surface on which the image to be projected is projected. For example, a projector can be provided to project an image onto a wall or screen. However, in cases where an image should be generated in the eye (e.g., with the aid of data glasses), it is possible to distinguish whether an image should be generated on the projection plane or, alternatively, on the projection surface. Regarding generating an image in the eye, there are essentially two possibilities.

[0042] (A) A system that operates using an optical waveguide. Here, an image is generated on a virtual intermediate plane or projection plane. This image is then replicated multiple times in two spatial directions within the optical waveguide. This unfolds the eyebox. The eyebox is typically the area where the observer's eye can recognize the image. In the case of an optical waveguide system, this is, for example, an area within a spectacle lens from which multiple copies of the image, replicated from the virtual intermediate plane, fall into the eye.

[0043] (B) In retinal scanning, the positional information of the virtual pixels to be illuminated in the image to be generated is transmitted into the angular information. In order to generate an image in the eye (on the retina), a mirror is embedded in the lens of, for example, data glasses, in the form of a holographic mirror invisible to the observer. Thus, the projection plane or surface can also be located directly in the eye, on the observer's retina.

[0044] In some aspects, the projection device is designed to display a second separate image during a second time window after displaying a first separate image during a first time window. Here, the first and second separate images can be particularly different from each other, so that a moving image can be generated by means of the projection device (at least as perceived by the human eye).

[0045] In some aspects, the projection device also includes light-forming optics arranged between the laser device and the deflection module. Here, the light-forming optics are specifically designed to collimate the laser emitted by the laser device, such that the substantially collimated laser beam hits the deflection module. "Substantially collimated" can be specifically understood here as: the laser beam is collimated as much as possible and is more focused than scattered. The light-forming optics can be designed such that the laser spot is very small in the region of the virtual pixel to be illuminated. For example, if collimation to 100% is not possible, the laser can have a focal point between the deflection module and the virtual pixel to be illuminated.

[0046] In some aspects, the control elements are designed to operate multiple laser sources in a pulsed manner. In particular, the laser sources are capable of operating in a pulsed manner within sub-time windows, such that the laser sources operate above the laser threshold of the laser source for up to 60% of the time, and particularly up to 40% of the time, within the sub-time windows.

[0047] In continuous wave mode (CW-mode), there is a danger: the laser source can experience thermal rollover even at low output power due to poor cooling. Operating modes with limited laser on-time (e.g., 10%-20%) and short pulse modulation (e.g., 2 ns-5 ns) allow for higher control currents without causing thermal rollover, thanks to heat dissipation between current pulses.

[0048] Specifically, the maximum optical power of a laser or laser source is limited by thermal collapse. This refers to the thermal overload caused by the laser's own heat generation. Laser sources with shorter ridges have smaller heat dissipation cross-sections and are therefore more prone to overheating earlier. Since the thermal collapse point of a laser is strongly influenced by power output (self-heating) and heat dissipation, excessive self-heating can be offset by pulsed operation of the laser source when using relatively small laser sources. In pulsed operation with longer intervals between current pulses, the thermal collapse point is shifted to a higher optical power, allowing the laser source to operate below this critical optical power without overheating.

[0049] Using a small laser source operating in pulsed mode offers the following advantages: the laser source has a relatively low laser threshold, yet it can operate efficiently above the laser threshold without overheating. Consequently, the laser source operates with high energy efficiency, and because of the low laser threshold, the proportion of the threshold current required to the total current required can be reduced. Correspondingly, the energy consumption of the projection device can be reduced.

[0050] Pulsed operation of the laser source during the sub-time window also has the following effect: the laser source is activated for only a very short period of time, a few nanoseconds. This causes the laser ridge, in the case of a laser source including a laser ridge, to oscillate incompletely and unstablely during this short period (the mode cannot be perfectly formed). Thus, compared to continuous wave operation, pulsed operation can, for example, achieve a broadening of the emission spectrum emitted by the laser source up to 2 nm. The possible difference of up to 2 nm in the laser emitted by the laser source can correspondingly cause a broadened emission spectrum with a slight offset relative to other laser sources, allowing illumination of pixels illuminated multiple times by the laser source with a laser having a wavelength spectral width of possibly 3 nm to 5 nm. Accordingly, the superposition of light from the pulsed laser source can cause spectral broadening of the entire laser emitted onto the virtual pixel with minimal difference (offset) in the separately emitted lasers, thereby, for example, suppressing optical artifacts in the projection device.

[0051] In some aspects, multiple laser sources exhibit low threshold current limits. For example, for laser sources emitting green or red light, the threshold current limit can be below 30 mA, particularly below 25 mA, at an operating temperature of approximately 25°C; and in the case of laser sources emitting red light, it can be below 10 mA, particularly below 6 mA. Specifically, laser sources are designed or designed to have the lowest possible threshold current. This is achieved, for example, by using a relatively short laser ridge. In this way, the current requirement required in the laser source's standby mode can be reduced, and current consumption can be minimized.

[0052] In some aspects, the control elements are designed to operate a laser source that should not emit light within a sub-time window below its laser threshold, specifically with a current greater than 0 or slightly below the laser threshold. This operation can be specifically referred to as a standby mode for the laser source and is used to quickly activate the laser source when a virtual pixel to be illuminated needs to be lit by the light from the laser source during the scanning of a single image, and when it is not necessary to fully power it on. Additionally, in the standby mode, it is possible to distinguish whether the laser source is operating in a "ready mode" slightly below the laser threshold (e.g., with a current of approximately 60% to 80% of the threshold current limit) or in a "sleep mode" with a current of only approximately 10% to 30% of the threshold current. This can be particularly relevant depending on whether the laser source must be activated to illuminate the virtual pixel within a foreseeable timeframe.

[0053] Specifically, the control element can be designed to take into account the image information of the image to be projected and put the laser source, which does not need to be activated during multiple sub-time windows, into a sleep mode, and put it into a ready mode shortly before the laser source must be activated, so that the laser source can be activated in the shortest possible time. In this way, the energy requirements of the projection device can be further reduced.

[0054] In some aspects, the control elements and / or deflection modules are designed to illuminate a first subset of theoretical pixels multiple times during a first time window using lasers from multiple laser sources, and to illuminate or not illuminate a second subset of theoretical pixels using only the laser from one of the multiple laser sources. Therefore, it is possible to illuminate specific virtual pixels of a single image more intensely than other areas, for example, by varying the brightness of areas displaying a single image during a single image session. Furthermore, it is possible to display prominent symbols in such a way that only pixels displaying the symbol can be illuminated or illuminated more brightly.

[0055] In some aspects, the multiple virtual pixels to be illuminated are arranged in rows and columns, and in particular, equidistant from each other. In other aspects, the multiple virtual pixels to be illuminated are arranged more closely together in a first region than in an adjacent second region. Especially in the case mentioned last, in the first region of the theoretical pixels, for example, some of the theoretical pixels may not be illuminated, while in the second region of the theoretical pixels, multiple or all of the theoretical pixels are illuminated. The illuminated virtual pixels are correspondingly farther apart from each other in the first region, resulting in a decrease in resolution in that region, while in the second region they are distributed closer together, i.e., the resolution is increased. However, it is also possible that, due to the design of the deflection module, the theoretical pixels already have densely packed areas and less densely packed areas, so that illuminating the theoretical pixels can cause the virtual pixels to be illuminated to be arranged in a manner with different densities from each other.

[0056] In some aspects, the projection device also includes an ambient light sensor designed to detect the brightness or brightness level of the environment surrounding the projection device. The control elements are also designed to, during a first time window, illuminate a first subset of theoretical pixels multiple times using lasers from multiple laser sources, based on the sensor signal from the ambient light sensor, and to illuminate a second subset of theoretical pixels using only the laser from one of the multiple laser sources. This allows pixels in a single image to be illuminated more intensely than other areas, for example, to display different brightness levels in areas of a single image during a single image session. This can be advantageous, for example, when an area of ​​the projection device is positioned in a brighter environment than other areas, under unfavorable light and shadow conditions. Furthermore, by means of the sensor signal from the ambient light sensor, it is possible to respond to different ambient brightness levels when switching between two single images, such that, for example, the first single image can be displayed brighter than a subsequent or slightly later second single image.

[0057] In some aspects, the control elements and / or deflection modules are designed to illuminate each of the theoretical pixels at most once during a second time window using the laser light from each of the multiple laser light sources individually. Accordingly, dynamic resolution can be provided by means of a projection device in such a way that more theoretical pixels can be illuminated for the second individual image than for the corresponding first individual image.

[0058] On the other hand, a data glasses system is provided, which includes a projection device according to some of the aspects described above. The projection device is designed herein to project a plurality of virtual and illuminated pixels onto at least one eye of the data glasses user. In particular, this could be, for example, AR glasses or VR (virtual reality) glasses.

[0059] In some aspects, the data glasses also include sensors for detecting the user's gaze direction. Specifically, it is possible to check essentially in real time which direction the user is looking. The control elements and / or deflection module can also be designed to, during a first time window and based on sensor signals from the sensors detecting the gaze direction, illuminate pixels in the central region located in the user's gaze direction multiple times using lasers from multiple laser sources, and illuminate pixels in the edge region surrounding the central region using lasers from one of the multiple laser sources. Thus, the area of ​​a single image within the user's field of vision can be displayed brighter than the area of ​​a single image located in the edge region surrounding the field of vision. However, it is also possible to explicitly illuminate areas not directly in the user's field of vision significantly brighter, for example, to guide the user's gaze in said direction or, for example, to warn the user.

[0060] In some aspects, the control element and / or deflection module are designed to, during a first time window and based on sensor signals from a sensor used to detect the direction of the gaze, illuminate at a higher resolution the area located in the central region in the user's gaze direction, for example, illuminating the area with the maximum possible theoretical pixels, and illuminate at a lower resolution the area located in the edge region surrounding the central region, i.e., illuminating fewer than the possible theoretical pixels in the edge region. Thus, the area of ​​a single image within the user's field of vision can be displayed at a higher resolution than the area of ​​a single image located in the edge region surrounding the field of vision.

[0061] According to another aspect, a method for illuminating multiple virtual pixels is proposed, wherein the multiple pixels generate a first individual image during a first time window. Here, the method can be performed specifically by means of a projection device according to some of the aspects described above, such that the aspects described for the corresponding projection device can also be synonymously applied to the method.

[0062] The method includes the following steps: The laser device operates, which has multiple laser sources. The laser sources are designed to emit laser light with substantially the same wavelength through multiple emission points arranged at relatively defined intervals, such that the laser sources emit laser light in the direction of the deflection module. The laser emitted onto the deflection module is sequentially deflected onto multiple virtual pixels to be illuminated. The deflection module is designed to simultaneously deflect the laser from a first laser source onto the first pixel, the laser from a second laser source onto the second pixel, and the laser from a third laser source onto the third pixel within a first sub-time window during a first time window; and Multiple laser sources and / or deflection modules are manipulated such that during a first time window, a third pixel is illuminated using the laser from a second laser source in a second sub-time window, and the third pixel is illuminated using the laser from a first laser source in a subsequent third sub-time window.

[0063] In some aspects, the steps of operating multiple laser sources include pulsed operation of multiple laser sources, particularly operating the laser sources above their laser threshold for up to 60% of the time, and especially up to 40% of the time, within a sub-time window.

[0064] In some aspects, the steps of operating multiple laser sources include setting a laser source to not emit light within a sub-time window to operate below its laser threshold.

[0065] In some aspects, the steps of manipulating multiple laser sources and / or deflection modules include: illuminating a first subset of multiple pixels multiple times with lasers from the multiple laser sources during a first time window, and illuminating a second subset of multiple virtual pixels with lasers from at most one of the multiple laser sources.

[0066] In some aspects, the steps of manipulating multiple laser sources and / or deflection modules include: Projecting multiple virtual pixels, for example, in rows and columns, onto a projection surface or plane, wherein the pixels are arranged equidistantly from each other; or Multiple virtual pixels are projected onto a projection surface or projection plane, for example, in a first region at a smaller spacing than they are relative to each other in an adjacent second region.

[0067] In some aspects, the steps of manipulating multiple laser sources and / or deflection modules include: during a second time window, illuminating each of a plurality of virtual pixels at most once with the laser light from each individual laser source among the plurality of laser sources, the plurality of virtual pixels generating a second individual image. Attached Figure Description

[0068] Based on other aspects of the proposed principles and implementation methods, embodiments and examples described below in conjunction with the accompanying drawings are disclosed.

[0069] Figure 1 The steps of the projection device and method based on the proposed principle are shown; Figure 2 Another step of the projection device and method based on the proposed principle is shown; Figure 3 Another step of the projection device and method based on the proposed principle is shown; Figure 4 The illustration shows the illumination of virtual pixels using a projection device based on the proposed principle; Figure 5 The illustration shows multiple virtual pixels illuminated within a first time window using a projection device based on the proposed principle. Detailed Implementation

[0070] The following embodiments and examples illustrate different aspects and combinations thereof according to the proposed principles. The embodiments and examples are not always drawn to scale. Similarly, different elements may be enlarged or reduced to highlight individual aspects. It goes without saying that the various aspects and features of the embodiments and examples shown in the figures can be arbitrarily combined with each other without affecting the principles of the invention. Some aspects have regular structures or shapes. It should be noted that slight deviations from the ideal form may occur in practice, but these will not violate the inventive concept.

[0071] Furthermore, the various figures, features, and aspects are not necessarily shown at the correct size, and the proportions between the elements are not necessarily correct in principle. Some aspects and features are highlighted by magnification. However, terms such as "above," "on top," "below," "under," "larger," and "smaller" are correctly displayed relative to the elements in the figures. Therefore, these relationships between elements can be deduced from the figures.

[0072] Figures 1 to 3 A projection device 1 is shown, which is used to illuminate a plurality of virtual pixels 2 on a projection surface 3. On the projection surface 3, the illuminated virtual pixels produce individual images, which are displayed or generated specifically during a first time window. The accompanying drawings exemplarily show only the actual virtual pixels to be illuminated, and the theoretical number of pixels that can be projected using device 1 can also be much larger.

[0073] In the illustrated case, the virtual pixel 2 is exemplarily displayed on the planar projection surface 3. The pixel can also be located in the virtual projection plane or an intermediate plane, as is the case, for example, when a single image is to be projected onto the user's eye using the projection device.

[0074] The projection device 1 includes a laser device 4 having multiple laser light sources 5a, 5b, and 5c. These laser light sources are arranged at a relatively defined spacing and designed to emit laser beams L1, L2, and L3 having substantially the same wavelength. In the illustrated case, the laser device 1 is exemplarily formed by a multi-laser configuration comprising three laser ridges 5a, 5b, and 5c, each ridge having a light exit window located at its end. The laser ridges are constructed on a common semiconductor substrate and have a lateral spacing of less than 10 µm relative to each other.

[0075] The projection device 1 also includes an optical element 7 for forming light, which is arranged in the optical path of the laser device 4 between the laser device 4 and the deflection module 6. Here, the optical element 7 for forming and, in particular, substantially collimating the lasers L1, L2, and L3 emitted by the laser device 4.

[0076] The deflection module 6 is designed to sequentially deflect lasers L1, L2, and L3 generated by laser sources 5a, 5b, and 5c onto a plurality of virtual pixels 2. For this purpose, the deflection module 6 is designed to be movable about at least one axis (at least two axes in the illustrated case), and in particular, to be rotatable. This is indicated in the figure by the axes shown by two dashed lines (one horizontal and one vertical) and by arrows at the ends of the axes.

[0077] In addition, such as Figure 1As shown, the deflection module 6 is designed to simultaneously deflect the laser L1 of the first laser source 5a to the first pixel 2a of the plurality of virtual pixels 2 during a first time window and within a first sub-time window, deflect the laser L2 of the second laser source 5b to the second pixel 2b of the plurality of virtual pixels 2, and deflect the laser L3 of the third laser source 5c to the third pixel 2c of the plurality of virtual pixels 2, without substantially moving. In the illustrated case, this exemplifies the use of three laser sources, where the light from the laser sources can be simultaneously deflected by the deflection module to three different pixels. However, it should be understood that this can also be done in a similar manner with more or fewer laser sources, or the light from all laser sources or a subset of laser sources can be simultaneously directed to the same pixel. Furthermore, it should be understood that combinations of the foregoing options are possible.

[0078] Furthermore, the projection device 1 includes a control element (not shown) designed to manipulate multiple laser light sources 5a, 5b, 5c and / or the deflection module 6, such that... Figure 2 As shown, during the first time window, the third pixel 2c of multiple virtual pixels 2 is illuminated by laser L2 of the second laser source within the second sub-time window, and as... Figure 3 As shown, the third pixel 2c is illuminated using laser L1 from the first laser source 5a within the subsequent third sub-time window. Correspondingly, during the first time window, the virtual pixel to be illuminated can be illuminated not only by the laser from one laser source but also by the lasers from multiple laser sources, thereby increasing the perceived brightness of the virtual pixel illuminated multiple times by the laser source. This is advantageous when using a human laser source, which has lower optical power compared to laser sources in known LBS systems. Thus, it is possible, as required, for example, to illuminate the virtual pixel efficiently with low luminous density using only one laser source, and simultaneously illuminate the virtual pixel with high luminous density by using the lasers from multiple laser sources, while still maintaining a high perceived overall brightness.

[0079] This is Figure 4 Summary and examples in Figure 4 The graphic form shown is for example pixels. Furthermore, in Figure 4 The characteristic curves of each laser source are shown to illustrate the advantages of smaller laser sources, especially in the required standby mode.

[0080] The laser characteristic curve has the shape of a hockey stick. There is no significant light emission P as the current I flows from zero to the threshold. Only when the current I exceeds the threshold does the laser ridge begin to emit lasing (stimulated emission), and this continues until the connected current I... f Both provide high luminous density P optAlthough the time for a laser to transition from zero to the operating region is only a few nanoseconds, if instantaneous turn-on characteristics (NTE, frequency 0.2 GHz) are required, the laser must operate slightly below the threshold. This results in permanent energy consumption. Generally speaking, it can be said that the higher the maximum optical power of the laser, the higher the laser threshold. Therefore, one aspect of this invention is to reduce the laser threshold by decreasing the size of the laser source and to compensate for the loss of optical power due to the size reduction by illuminating the pixel multiple times. Thus, while the energy consumption required to illuminate the pixel at the same brightness cannot be reduced, the current during the standby time between illuminated pixels can be significantly reduced.

[0081] The diagram on the left shows... Figures 1 to 3 The laser source is shown with various characteristic curves. The laser source can be activated and deflected onto a virtual pixel within a sub-time window to illuminate that pixel. Above a threshold, the laser source can operate along the laser characteristic curve until the connection current I... f The optimal luminous density P opt Depending on the connected current, the emitted luminous density can be adapted to each laser source above the laser threshold. The right-hand figure exemplarily shows the cascaded connection of individual laser characteristic curves for a single pixel. This aims to illustrate that, even with multiple smaller laser sources, it is possible to achieve an optical luminous density P comparable to that achieved with a larger laser source. opt .

[0082] Figure 5 It is also illustrated, exemplarily, for a time window, that different pixels 2a, 2b, and 2c can be illuminated with different brightness levels. This can be achieved, on the one hand, by adapting the luminous density emitted by the laser light source (see L1 pixel 2a and L2 pixel 2b), and / or by increasing the luminous density of the pixel by illuminating a pixel with light from multiple laser light sources (L1 + L2 + L3) during the time window, thereby increasing the perceived total brightness of that pixel.

[0083] Reference number list

[0084] 1. Projection device

[0085] 2, 2a, 2b, 2c, 2d, 2e pixels

[0086] 3. Projection surface, projection plane

[0087] 4. Laser device

[0088] 5a, 5b, 5c laser light sources

[0089] 6 Deflection Module

[0090] 7 Optical components that form light

[0091] L1, L2, L3 lasers

[0092] T1, T2 time windows

[0093] T1, t2, t3 are sub-time windows.

Claims

1. A projection device (1) for illuminating a plurality of virtual pixels (2, 2a, 2b, 2c), wherein, The plurality of virtual pixels (2, 2a, 2b, 2c) generate a first individual image during a first time window (T1), and the projection device includes: The laser device (4) has multiple laser sources (5a, 5b, 5c) designed to emit lasers (L1, L2, L3) with substantially the same wavelength through multiple emission points arranged at relatively defined intervals. A deflection module (6) is designed to sequentially deflect lasers (L1, L2, L3) emitted from the emission point onto the plurality of virtual pixels (2, 2a, 2b, 2c). The deflection module is also designed to, during the first time window (T1), deflect the laser (L1) of the first laser source (5a) onto the first pixel (2a) of the plurality of virtual pixels, deflect the laser (L2) of the second laser source (5b) onto the second pixel (2b) of the plurality of virtual pixels, and deflect the laser (L3) of the third laser source (5c) onto the third pixel (2c) of the plurality of virtual pixels within a first sub-time window (t1). A control element designed to manipulate the plurality of laser light sources (5a, 5b, 5c) and / or the deflection module (6) such that, during a first time window (T1), the third pixel (2c) of the plurality of virtual pixels is illuminated by the laser (L2) of the second laser light source (5b) in a second sub-time window (t2), and the third pixel (2c) is illuminated by the laser (L1) of the first laser light source (5a) in a subsequent third sub-time window (t3).

2. The projection device according to claim 1, wherein, The control element is designed to operate the plurality of laser sources (5a, 5b, 5c) in a pulsed manner, particularly to operate the laser sources (5a, 5b, 5c) above the laser threshold of the laser source for up to 60% of the time, and especially up to 40% of the time, within sub-time windows (t1, t2, t3).

3. The projection device according to claim 1 or 2, wherein, The control element is designed to ensure that laser sources (5a, 5b, 5c) that should not emit light within sub-time windows (t1, t2, t3) operate below the laser threshold of the laser source.

4. The projection device according to any one of claims 1 to 3 further includes an optical element (7) for forming light, the optical element being arranged between the laser device (4) and the deflection module (6), and the optical element being particularly designed for collimating the laser (L1, L2, L3) emitted by the laser device (4).

5. The projection device according to any one of claims 1 to 4, wherein, The control element and / or the deflection module (6) are designed to illuminate a first subset of the plurality of virtual pixels (2, 2a, 2b, 2c) multiple times during the first time window (T1) using the lasers of the plurality of laser sources (5a, 5b, 5c), and to illuminate a second subset of the plurality of virtual pixels (2, 2a, 2b, 2c) using the laser of one of the plurality of laser sources (5a, 5b, 5c).

6. The projection device according to any one of claims 1 to 5, wherein, The plurality of virtual pixels (2, 2a, 2b, 2c) are arranged in rows and columns and, in particular, are arranged equidistantly from each other.

7. The projection device according to any one of claims 1 to 5, wherein, The plurality of virtual pixels (2, 2a, 2b, 2c) are arranged more closely together in the first region as they are in the adjacent second region.

8. The projection device according to any one of claims 1 to 7, further comprising an ambient light sensor, wherein, The control element is designed to illuminate a first subset of the plurality of virtual pixels (2, 2a, 2b, 2c) multiple times during the first time window (T1) using the lasers of the plurality of laser light sources (5a, 5b, 5c) based on the sensor signal of the ambient light sensor, and to illuminate a second subset of the plurality of virtual pixels (2, 2a, 2b, 2c) using the laser of one of the plurality of laser light sources (5a, 5b, 5c).

9. The projection device according to any one of claims 1 to 8, wherein, The control element and / or the deflection module (6) are designed to illuminate each of the plurality of virtual pixels at most once during a second time window (T2) using the laser (L1, L2, L3) of each individual laser source among the plurality of laser sources (5a, 5b, 5c).

10. A data glasses (10) comprising a projection device (1) according to any one of claims 1 to 9, wherein, The projection device (1) is designed to project the plurality of virtual pixels (2, 2a, 2b, 2c) into at least one eye of the user of the data glasses.

11. The data glasses of claim 10, further comprising a sensor for detecting the direction of the user's gaze, wherein, The control element and / or the deflection module (6) are designed to, during the first time window (T1) and according to the sensor signal of the sensor, illuminate the virtual pixel located in the central region in the user's line of sight multiple times using the lasers of the plurality of laser light sources (5a, 5b, 5c), and illuminate the virtual pixel located in the edge region surrounding the central region using the laser of at most one of the plurality of laser light sources (5a, 5b, 5c).

12. A method for illuminating a plurality of virtual pixels (2, 2a, 2b, 2c), wherein, The plurality of virtual pixels (2, 2a, 2b, 2c) generate a first individual image during a first time window (T1), the method comprising the following steps: The laser device (4) is operated, which has multiple laser sources (5a, 5b, 5c) designed to emit light with substantially the same wavelength through multiple emission points arranged at relatively defined intervals, such that the laser sources (5a, 5b, 5c) emit lasers (L1, L2, L3) toward the deflection module (6). The lasers (L1, L2, L3) emitted onto the deflection module (6) are sequentially deflected onto the plurality of virtual pixels (2, 2a, 2b, 2c), wherein the deflection module (6) is designed to deflect the laser (L1) of the first laser source (5a) onto the first pixel (2a) of the plurality of virtual pixels within a first sub-time window (t1) during the first time window (T1), deflect the laser (L2) of the second laser source (5b) onto the second pixel (2b) of the plurality of virtual pixels, and deflect the laser (L3) of the third laser source (5c) onto the third pixel (2c) of the plurality of virtual pixels; and Manipulate the plurality of laser light sources (5a, 5b, 5c) and / or the deflection module (6) such that during the first time window (T1), the third pixel (2c) of the plurality of virtual pixels is illuminated by the laser (L2) of the second laser light source (5b) in the second sub-time window (t2), and the third pixel (2c) is illuminated by the laser (L1) of the first laser light source (5a) in the subsequent third sub-time window (t3).

13. The method according to claim 12, wherein, The steps of operating the plurality of laser sources (5a, 5b, 5c) include pulsed operation of the plurality of laser sources (5a, 5b, 5c), particularly such that the laser sources (5a, 5b, 5c) operate above the laser threshold of the laser source for up to 60% of the time, and particularly up to 40% of the time, within sub-time windows (t1, t2, t3).

14. The method according to claim 12 or 13, wherein, The step of operating the plurality of laser sources (5a, 5b, 5c) includes causing the laser sources (5a, 5b, 5c) that are set to not emit light during sub-time windows (t1, t2, t3) to operate below the laser threshold of the laser source.

15. The method according to any one of claims 12 to 14, wherein, The steps of manipulating the plurality of laser light sources (5a, 5b, 5c) and / or the deflection module (6) include: using the lasers of the plurality of laser light sources (5a, 5b, 5c) multiple times during the first time window (T1) to illuminate a first subset of the plurality of virtual pixels (2, 2a, 2b, 2c), and using the laser of at most one of the plurality of laser light sources (5a, 5b, 5c) to illuminate a second subset of the plurality of virtual pixels (2, 2a, 2b, 2c).

16. The method according to any one of claims 12 to 15, wherein, The steps of manipulating the plurality of laser light sources (5a, 5b, 5c) and / or the deflection module (6) include: The plurality of virtual pixels (2, 2a, 2b, 2c) are projected, in particular, onto the projection plane (3) or projection plane in a row and column manner, wherein the virtual pixels are arranged, in particular, at equal intervals from each other; or The plurality of virtual pixels (2, 2a, 2b, 2c) are projected in the first region onto the projection surface (3) or projection plane with a relatively smaller spacing between them compared to that in the adjacent second region.

17. The method according to any one of claims 12 to 16, wherein, The steps of manipulating the plurality of laser light sources (5a, 5b, 5c) and / or the deflection module (6) include: using the laser (L1, L2, L3) of each individual laser light source among the plurality of laser light sources (5a, 5b, 5c) at most once during a second time window (T2) to illuminate each of the plurality of virtual pixels.

Images