WO2010079072A1

WO2010079072A1 - Projection module

Info

Publication number: WO2010079072A1
Application number: PCT/EP2009/067366
Authority: WO
Inventors: Jan Oliver Drumm; Benjamin Jobst; Christian Gammer; Claus Seibert; Jens Richter; Ulrich STEEGMÜLLER; Karsten Auen; Michael Kühnelt; Thomas Schwarz
Original assignee: Osram Gesellschaft mit beschränkter Haftung
Priority date: 2009-01-08
Filing date: 2009-12-17
Publication date: 2010-07-15
Also published as: DE102009004117A1

Abstract

The invention relates to a projection module, comprising at least one semi-conductor light source and at least one integrated circuit, which are arranged on a common substrate. The portable projection device comprises at least one such projection module.

Description

Projection module

The invention relates to a projection module, in particular a laser projection module, and a portable projection device which has at least one such projection module.

Semiconductor-based image projection systems are known, e.g. B. LED-based micro-lens actuators ("DLP"), LCD or LCoS ("Liquid Crystal on Silicon") projectors, as well as scanning systems with laser light sources. The known projection systems have in common that they are assembled from many different individual components, which are mounted separately from each other.

It is the object of the present invention to provide a particularly compact and robust possibility for image projection.

This object is achieved by means of a projection module and a portable laser projection apparatus according to the respective independent claim. Preferred embodiments are in particular the dependent claims.

The projection module has at least one semiconductor light source and at least one integrated circuit, which are arranged on a common substrate. The at least one integrated circuit can be used in particular for the operation of the at least one semiconductor light source, for. As a driver, for example, for the modulation of beam intensity levels ("grayscale") or so-called. "Sequential Color". Due to the close arrangement on the common substrate, a miniaturization of the projection device can be achieved, which is particularly advantageous in devices with a small installation space, for example in portable laser projection devices such as mobile phones, PDAs, music players, projectors, etc. a particular achievable miniaturization of the projection module with a height of less than 7 mm is a prerequisite for installation in (flat) mobile devices. The compactness of the module also enables an improved thermal connection. In addition, in contrast to a distributed arrangement due to the rigidity of the substrate, a much reduced susceptibility to shock and / or vibration results. Also, the electrical lines between the components need not be made mechanically strong. Due in part to the short distances between the components (in particular the lasers and the electronics or integrated circuit) and the comparatively high freedom of design in the wiring, such an arrangement is readily electrically connectable and suitable for high frequencies. Also, the short lengths of support capacitors can be advantageously placed, so that on the power supply lines of the laser acting disturbances (eg line impedances, RF coupling of noise, series resistances and capacitances, etc.) can be reduced and an improved rise time can be achieved.

Thus, it is possible to provide a higher-value integrated component (here: projection module with integrated circuit, in particular integrated driver, with a defined external electronic and optical interface). The transfer parameters of the interfaces do not depend on the influences of the ambient conditions (eg temperature) and on the manufacturing tolerances of the lasers (production-related differences in output power and drive voltage). As a result, a large production bandwidth of laser components for the production of the modules can be used. The interface parameters of the electronic interface may include, for example, an RGB gray-scale signal, a power supply, serial communication channels, as well as an H-sync signal and a V-sync signal. The H-Sync signal can be used as a so-called "Power Down" signal (eg to switch off the laser drivers at the line edge). The so-called "V Sync "signal can be used to start a calibration cycle (for example, to detect a laser threshold when the vertical axis returns in quasi-static drive or detect a current-to-maximum current setting), thus incorporating the electrical or electronic interface No advantage is given to the fact that the projection module can be combined with all projection mirrors or other imaging optics, without having to make any special adaptation to the special projection or imaging method, which in turn leads to the possibility of a high-volume signal Manufacturing and thus the advantage of lower module costs.

The external electronic interface can be understood as a hardware interface. Another possibility is a compensation of the above-mentioned effects in a software implementation, in which case the external electronic interface is a software interface that can be located in a video processing unit upstream of the projection module.

The optical interface, for example, by specifying a distance of one or more focal points of the respective module outlet opening and the local

Beam diameter be defined over the full (1 / e ² ) width. Possible values for this are a maximum beam diameter of 400 μm at a distance of more than 300 mm before a beam exit from the projection module.

Due to the existence of a simple and universally applicable electronic and optical interface, a fast system design is possible.

On the substrate and light sensors such as photodiodes may be mounted, for. B. for a control or regulation of a Radiation intensity of the laser by means of feedback of the sensor measured values to the integrated circuit or driver electronics ("photodiode feedback"). The photodiode feedback also allows monitoring of a limit on the allowable laser power and can thereby be used to monitor eye safety.

Furthermore, switching regulators for driving the laser diodes and / or supporting capacitors can be arranged on the substrate.

In the projection module, an impedance matching between an integrated circuit or a driver and at least one of the laser diodes can be implemented. This enables efficient drive pulses with improved rise times of the current pulse edges.

The feature included in the module electronics to access Look-Up Tables (LUT) allows compensation for the curvature of the laser characteristics. Alternatively, the LUTs can also be stored in the software driver.

In the projection module, an adjustment of a color mixture and / or a stabilization of the white point can be implemented or be part of the module properties, which results in increased image quality. The white point control can be done with the help of an optional optical filter. The optical filter is advantageously arranged in the feedback beam path or test beam path of the red laser. By means of the filter, a change in the color locus of the red laser is compensated, so that the color location of the entire projection module remains substantially constant. Alternatively, optical filters may be arranged in other feedback beam paths, e.g. B. in the blue feedback beam path or Probestrahlengang. The semiconductor light source may include a laser, e.g. As a laser diode or an optically pumped semiconductor laser (OPSL, "optically pumped semiconductor laser"), have, or even a light emitting diode.

The type of integrated circuit is basically not limited and may include, for example, a digital, an analog and / or a mixed digital and analog ("mixed signal") integrated circuit, for. B. ASIC, digital signal processor ("DSP"), FPGA ("field programmable gate array") or microcontroller designed.

The type of substrate is basically not limited and may include, for example, solid or multi-layered body, z. B. also boards. For good thermal bonding, preference is given to substrates which have a thermal conductivity λ of more than 100 W / (m-K), eg. As metallic Vollkörpersubstrate of Cu, Al, Mg or alloys thereof or solid ceramic substrates of AlN, Al2O3, etc. As a multi-layer substrates come z. As ceramic LTCC body in question. Particularly preferred is a substrate made of AlN, since this has a thermal conductivity of 180 W / (m-K) and does not conduct electricity. This achieves, among other things, a very good thermal connection with at the same time uncritical wiring of the components.

The substrate may advantageously be a post-processed body, in particular a ceramic body z. B. of AlN ceramic, since such a ceramic body can be produced comparatively inexpensive. However, metal bodies can be refinished, in particular milled. The substrate can be made for easy injection molding with or without post-processing, e.g. B. from thermally well-conducting plastic. The at least one semiconductor light source may comprise at least two semiconductor light sources, wherein main beam directions of the light beams emitted by the semiconductor light sources are collinear. In the case of light sources, such as lasers, which emit sharply focused light, it can be said that the light rays are collinear.

The at least two semiconductor light sources may comprise all semiconductor light sources of the same type used by the laser projector, e.g. B. laser diodes. This results in a high integration factor with a simple structure. However, the at least two semiconductor light sources can also comprise all the semiconductor light sources used by the laser projector, that is also of different types, eg. As laser diodes and optically pumped semiconductor laser. This results in an even higher integration factor with improved thermal coupling.

For example, at least one red (i.e., a red color emitting light beam) laser diode and one blue (i.e., blue color emitting light beam) laser diode may be disposed on a common substrate. In addition, a green (i.e., a green color emitting light beam) optically pumped semiconductor laser may be additionally disposed on the common substrate. An additional arrangement of the green laser causes a further miniaturization of the entire laser projector and a further increase in the thermal and electrical connection. If green laser diodes become available, their use in conjunction with blue and red laser diodes will also be possible.

The light sources are not limited to the color combination RGB, but it may be mounted differently colored light sources on the substrate. Also, one or more light sources per color may be mounted on the substrate, e.g. B. as a combination RRGB, RGGB, RGBB, RGGBB, etc. The main beam directions of the light beams emitted by the plurality of semiconductor light sources advantageously do not deviate from each other by more than 5 mrad, especially not more than 3 mrad. As a result, particularly simple optics for beam guidance can be used, and a particularly precise beam guidance can be achieved.

Furthermore, at least one optical element which is set up and arranged for the beam guidance of at least one of the light beams which can be emitted by the at least one semiconductor light source can be arranged on the substrate. In this case, an optical element may be a lens, a refractive element, etc., and is not limited to any particular type of beam-influencing elements.

The at least one optical element can have at least one beam-shaping optical system, wherein advantageously each of the at least one semiconductor light source can be optically connected downstream of a beam-shaping optical system. By means of the beam-shaping optical system, it is possible, in particular, to modify a light beam emerging from a semiconductor light source, e.g. In relation to a collimation property, a beam width or a beam direction. The beam-shaping optics can be used in particular as a primary optic. The integration of the beam shaping optics results in the additional advantage of a particularly increased long-term stability and shock compatibility of the system with simultaneous further miniaturization.

The at least one optical element may alternatively or additionally comprise at least one beam combination optics for combining the light beams emitted by a plurality of semiconductor light sources. As a result, the module can be used particularly advantageously in the context of known imaging methods. The beam combination optics is preferably designed as a prism structure. In particular, the prism allows, among other things for each light beam or color channel transmission in mutually orthogonal directions.

At least one imaging element may be disposed on the substrate, e.g. For example, one or more mirrors (scanning mirrors, DLP mirrors, etc.). Through its additional integration, a further miniaturization of the entire laser projector is achieved, as well as a further increase in long-term stability and shock tolerance. The imaging element can preferably be arranged on a beam path of a light beam combined from individual light beams.

The at least one integrated circuit can have at least one digital or mixed-signal integrated circuit and at least one analog integrated circuit, wherein the analog integrated circuit can be connected in front of a semiconductor light source for driving them and the digital or mixed integrated circuit of the analog integrated circuit can be connected upstream as a digital interface. As a result, in the case of the digital circuit, known low-cost, highly integrated manufacturing methods can be used, while less highly integrating production methods are used for the analog power stages, but which are optimized for driving the laser diodes. This optimization can be aimed, in particular, in the direction of a very fast rise time of the drive signal with simultaneously comparatively high driver currents.

The at least one integrated circuit can have at least one - in particular analog - integrated circuit for signal conditioning, which is in each case interposed between a digital or mixed integrated circuit and an analog integrated drive circuit. This further division will increase the flexibility in the application and improvement of the manufacturing achieved by separating function blocks with different requirements (performance, bandwidth, throughput).

The at least one integrated circuit can have at least one integrated circuit for image processing, which can be connected upstream of the digital or mixed integrated circuit, for example. By means of image processing, z. In the form of a video pre-processing unit, an adaptation of the supplied image information (eg a VGA signal) to the projection method used, for example a scan method, can be carried out.

The lasers may each be preceded by a switching regulator, namely as a separate component or integrated in the integrated circuit, in particular in an analog power stage. The switching regulator can be specifically set to the associated laser. On the one hand, the measurement of the forward voltage of the corresponding laser diode when the maximum current is applied can take place in a so-called "end of line" test. The measured quantity can be stored in a look-up table or look-up table of the projection module and used to set a suitable transformer voltage. This ensures improved efficiency. Another possibility of setting the switching regulator can be carried out by a module-internal determination of a voltage drop of a suitable measured variable in the power path of the integrated circuit or electronics. For example, a voltage drop across a measuring resistor, a transistor or the laser diode itself may be used.

The portable laser projection device has at least one such projection module. Thereby, a particularly compact and reliable portable projection apparatus, in particular laser projection apparatus, with the capability for image projection can be provided. Portable laser projection devices For example, mobile phones, PDAs, music players (eg, "MP3 players"), dedicated projectors, etc. may be included.

In the following figures, the invention will be described schematically with reference to exemplary embodiments. It can be provided with the same reference numerals for better clarity identical or equivalent elements.

FIG. 1 shows a plan view of a sketch of a laser projection module according to a first embodiment; FIG.

2 shows a plan view of a sketch of a laser projection module according to a second embodiment;

3 shows a plan view of a sketch of a laser projection module according to a third embodiment;

4 shows a plan view of a sketch of a laser projection module according to a fourth embodiment;

5 shows a plan view of a sketch of a laser projection module according to a fifth embodiment;

6 shows a plan view of a sketch of a laser projection module according to a sixth embodiment;

7 shows a plan view of a sketch of a laser projection module according to a seventh embodiment;

8 shows a plan view of a sketch of a laser projection module according to an eighth embodiment;

9 shows a plan view of a sketch of a laser projection module according to a ninth embodiment;

10 shows a plan view of a sketch of a laser projection module according to a tenth embodiment; FIG. 11 is a plan view showing a sketch of a beam combining prism of the laser projection module of the tenth embodiment; and

12 shows a plan view of a sketch of a laser projection module according to an eleventh embodiment.

1 shows a plan view of a laser projection module Ia for installation in a compact laser projector. The laser projection module Ia has as a substrate 2 a block-shaped block of milled aluminum nitride ceramic, on the front side 3 of which a red laser diode 4, a blue laser diode 5 and an integrated circuit in the form of an ASIC 6 are applied. The ASIC 6 can still be mounted on a printed circuit board (not shown). The two laser diodes 4, 5 are arranged side by side and aligned both with their respective main beam direction in the x direction. The associated beam paths 7 and 8, which indicate the main beam direction, are essentially collinear with each other with a linearity deviation of less than 3 mrad. By means of the ASIC 6, the two laser diodes 4, 5 are driven. The ASIC 6 and the laser diodes 4, 5 are electrically connected to each other via bonding wires, not shown here. Due to the high thermal conductivity of aluminum nitride ceramic of about 180 W / (mK) a very good thermal heat dissipation of the components 4, 5, 6 is achieved, for example, to a rear-mounted heat sink (not shown) or a housing of the laser projector (o Fig.). Furthermore, due to this close arrangement on the common substrate 2, a miniaturization of an associated laser projection device is achieved, which is advantageous in particular for use in devices with a small installation space, for example in portable laser projection devices such as mobile telephones, PDAs, music players, dedicated projectors, etc. In contrast to a distributed arrangement due to the rigidity of the substrate, a much reduced susceptibility to shock and / or Vibration. In addition, the electrical lines between the components 4, 5 and 6 need not be made mechanically resilient. Due in part to the short distances between the components 4, 5, 6 and the comparatively high design freedom in the wiring, such an arrangement is easily electrically connectable and suitable for high frequencies.

During operation of the laser projection module, image signals (eg line-like VGA signals) are fed to the ASIC 6 for generating an image, which is pixel-like in particular, which converts these image signals into analog drive signals suitable for driving the laser diodes 4, 5. For this purpose, a digital data processing stage for converting the pixel signals can be integrated in the ASIC, as well as an analog power stage for generating the analog driver signals. The drive signals are fed to the laser diodes 4, 5 which generate corresponding light signals therefrom.

The laser projection module Ia shown can represent a part of a laser projection apparatus which has further elements other than the laser projection module Ia for generating an image, for example optics for beam guidance, a video processing unit, a housing, etc. The laser projector may also separate one from the laser projection module Ia having arranged green laser to represent a full-color image in RGB space can. While red and blue laser diodes can be manufactured in substantially the same way, green laser diodes are not yet available; Therefore, instead of a green laser diode, a frequency-doubling green laser is used.

In detail, the red laser diode 4 and the blue laser diode 5 are constructed so that a laser diode (LD) chip 4a or 5a serves as the laser source, which is surrounded by a package ("package") 4b and 5b, respectively. The light emitted by the respective laser diode chip 4a and 5a, respectively, can be transmitted through a front window 4c, 5c emerge from the package 4b, 5b. The packages 4b, 5b may have the following properties: they are solderable as Surface Mounted Devices (SMD); a thermal resistance of the package 4b, 5b is less than 25 K / W; the packages 4b, 5b are gas-tight and may advantageously be filled with a protective gas atmosphere (eg nitrogen or dry air); their dimensions may not exceed 6mm (width) x 4mm (height) x 4mm (depth); a distance from the window 4c, 5c to the laser chip 4a, 5a or to the respective laser facet is less than 0.25 mm; electrical contacts 4d, 5d are led out in isolation, so that the housing 4b, 5b is not at a potential; orthogonal to the electrical contacts 4d, 5d, a heat sink (o. Fig.) Is arranged; the laser diodes 4, 5 are held by means of a mechanical support mechanism (not shown).

2 shows in plan view of the front side 3 of a laser projection module Ib the same components as in the laser proj ektionsvorrichtung Ia of FIG 1, now additionally a green frequency doubling laser (OPSL) 9 is mounted on the substrate 2. The green OPS laser 9 is also operated via the ASIC 6. The ASIC 6 is electrically connected to the lasers 4,5,9, via bonding wires 26; the associated contact surfaces have no reference numerals for the sake of clarity. The beam path 10 of the green laser 9, which indicates the main emission direction, is also collinear with a collinearity deviation of less than 3 mrad to the two other beam paths 7, 8. The lasers 4, 5, 9 thus emit in the same direction, ie parallel to the x-axis, essentially, ie with a negligible collinearity deviation of less than 3 mrad for practical purposes. An additional arrangement of the green laser 9 causes an additional miniaturization of the entire laser projector and a further improvement of the thermal and electrical connection. FIG. 3 shows a laser projection module Ic similar to the laser projection module Ib from FIG. 2, but now optical elements in the form of aspherical lenses 11 are additionally mounted on the front side 3 of the substrate 2. Each of the lasers 4, 5, 9 is optically connected downstream of one of the lenses 11 for beam shaping of the light beam emitted by the laser 4, 5 and 9, respectively. Under a beam shaping can be understood in particular a focusing and / or collimation of the individual laser beams. The lenses 11 are designed for miniaturization of the laser projection module Ic as micro-optics. An adjustment and fixation of the lenses 11 takes place on the common substrate 2. The integration of the lenses 11 results in the additional advantage of a particularly increased long-term stability and shock compatibility of the laser projector with simultaneous further miniaturization.

FIG. 4 shows a laser projection module Id similar to the laser projection module Ic from FIG. 3, in which the lenses 11 are optically followed by a common optical element 12 for the beam combination. This secondary beam combination optics 12 serves to superimpose the light beams emerging from the lenses 11 in a directional and congruent manner and thereby to produce a single combined light beam whose position is indicated here by the beam path 13. In order to achieve the beam combination, the beam combination optics 12 are configured as an optical element with multiple reflection surfaces 14a, 14b, 14c which are permeable on one side. The first reflection surface 14a reflects the light beam emitted from the red laser diode 4, which has passed through the associated lens 11, by 90 ° in the (-y) direction. The second reflection surface 14b also reflects the light beam emitted by the blue laser diode 4, which has passed through the associated lens 11, by 90 ° in the (-y) direction and at the same time allows the already reflected red light beam to pass through. Behind the second reflection surface 14b thus already runs a combined red-blue light beam, the following at the third reflection surface 14c by - 90 ° again is deflected in the x direction. At the same time, the light beam emitted by the green OPS laser 4 is transmitted through the third reflection surface 14 c so that a combined RGB light beam can be generated behind the third reflection surface 14 c.

FIG. 5 shows a laser projection module Ie similar to the laser projection module Id from FIG. 4, in which an imaging element 15 is additionally arranged on the substrate 2. The imaging element 15 is optically connected downstream of the beam combination element 14 and thus directs the combined light beam 13 emitted by the beam combination element 14 onto an external image projection surface (not illustrated). The imaging element 15 may be, for example, a two-dimensional MEMS scanner, a combination of sequential one-dimensional MEMS scanners, a DLP mirror, and so on. The scanners are mounted accordingly movable. The ASIC 6 can then also be used to control the imaging element 15. For example, in the ASIC 6, the corresponding drive data for the lasers 4, 5, 9 and the imaging element 15 can then be generated from the incoming digital pixel data. For example, a corresponding angular position of the imaging element 15 may be set in the ASIC 6 to generate a tricolor pixel on the image projection surface together with a corresponding temporal modulation of the respective laser 4, 5, 9. The additional integration of an imaging element on the laser production module Ie an even greater miniaturization of the entire laser projector is achieved, as well as a further increase in long-term stability and shock tolerance. For example, this structure can be accommodated on the front side 3 of the substrate 2 in an area of only 35 mm × 20 mm, and this at a height (along a z-extension) of less than 10 mm. FIG. 6 shows a further laser projection module If similar to the laser projection module Ie from FIG. 5, but now the ASIC 6 present in the laser projection unit is divided into a plurality of integrated components 16, 17 which fulfill the same functions as an ASIC 6, but more compactly and are cheaper to produce. In particular, the functions of the ASIC 6 are now divided into a respective power stage 16 per laser 4, 5, 9 and a common digital interface 17. While the power stages 16 are implemented as analog integrated circuits, the digital interface 17 is implemented as a digital integrated circuit or "mixed signal" circuit. As a result, in the case of the digital interface 17, known low-cost, highly integrated production methods can be used, while for the analog power stages 16, less highly integrating production methods are used, which are optimized for driving the laser diodes 4, 5, 9. This optimization aims in particular in the direction of a very fast rise time of the drive or drive signal at the same time as comparatively high currents. For example, a rise time in the range of only 1 ns to 1.5 ns may be provided at a current in the range of 500 mA. The digital interface 17 may, for example, have an SPI ("Serial Peripheral Interface") bus as well as a digital / analog converter as an interface to the power stages 16. The power stages 16 are also set up for signal conditioning.

The laser projection module If further has a plug 18 connected to the digital interface 17 for its power supply and for data transmission of narrowband signals, eg. B. of temperature sensor signals of a substrate 2 arranged on the temperature sensor on. Furthermore, a plug 19 connected to the digital interface 17 for broadband image signal transmission, in particular video signal transmission, is applied to the substrate 2. The laser projection module If can still further digital and / or in particular re analog functional units (such as delay stages, analog multiplexers, control elements, analog arithmetic functions and power drivers) have, however, are not shown. The power stages 16 may have, among other things, a level adjustment with respect to voltage and / or current of the signals as well as a line termination for increasing the signal integrity for signal conditioning. One of the benefits of this split is that it enables the use of a variety of semiconductor technologies for electronics. Furthermore, an adaptation to special applications is possible, which in turn optimizes the performance. Furthermore, such a split increases the production yield ("ASIC Yield"). In addition, a thermal and electrical decoupling of power elements, precision elements such as the D / AWandler and digital elements of the integrated electronics is achieved.

FIG. 7 shows a laser projection module Ig similar to the laser projection module If from FIG. 6, wherein a signal conditioning part 21 for level matching and line termination for each laser 4, 5, 9 is extracted from the digital interface 17 and shown as a separate circuit the substrate 2 is mounted. The digital interface 20 also has the external interfaces which are connected via the plugs 18, 19, as well as the SPI. The signal conditioning circuits 21 are executed individually for each color (R, G and B); In an alternative embodiment, however, a signal conditioning circuit for all colors or lasers 4, 5, 9 can also be provided. This further division makes it possible to increase the flexibility in the application and to improve the production yield by separating functional blocks of the ASIC with different requirements (performance, bandwidth, throughput). FIG. 8 shows a further laser projection module Ih in which, in addition to the laser projection module Ig from FIG. 7, the digital interface 20 is preceded by a video pre-processing unit 22 attached to the substrate 2, which is functionally connected to two video memories 23. Alternatively, only one video memory 23 may be used, or more than two video memories 23 may be used. By means of the video pre-processing unit 22, an adaptation of the picture information (picture point signals) of the picture source, which may be line-and column-oriented, supplied via the plug 19 to the projection method used, for example a scanning method, is performed. In this case, the video pre-processing unit can use image processing algorithms, wherein the image information can be temporarily stored in the video memory 23. The implementation of video pre-processing results in a reduction in the dimensions of the entire projection system, ie the laser projector. Advantageously, a simple adaptation to different applications by a standardized interface to imaging systems (personal computer, laptop, PDA, smartphone, etc.) is possible.

FIG. 9 shows a further laser projection module Ii, which, in contrast to the embodiments described above, is designed for one color only ("single color laser module") and accordingly also has only one laser 4, 5 or 9 mounted on the substrate. In this case, for easy alignment of the laser 4, 5 or 9 on the substrate 2, a mechanical stop 24 is provided, against which the laser 4, 5 or 9 can be aligned to its mounting. For the electrical connection of the laser 4, 5 or 9, a conductor 25 is led from the laser 4, 5 or 9 around the stop 24 to an ASIC 6 also mounted on the substrate 2 on the electrically insulating front side 3 of the substrate 2 , The ASIC 6 is connected to the electrical conductor 25 via bonding wires 26. In addition, the ASIC 6 with the laser 4, 5 or 9 connected via an electrical line, which comprises a pair of bonding wires 26, which are guided by the ASIC 6 to a located on the mechanical stop 24 contact pad 27, wherein the electrical contact pad 27 with the laser 4, 5 or 9 via another pair of bonding wires 26 is electrically connected. On the input side, the ASIC 6 is connected to a plug 28 for voltage and signal supply. The monochrome laser projection module Ii can in particular be configured in the variants already shown for the multicolor laser projection module Ia-Ih, ie, for example, by additional mounting of optics or driver chips on the substrate 2. The lasers 4 and 5 can also be described as "bare die". be executed.

10 shows a plan view of a sketch of a laser projection module Ij according to a tenth embodiment. In contrast to FIG. 4, the ASIC 6 is shown here mounted on a printed circuit board 28. In contrast to the laser projection module Id of the fourth embodiment, the intensity of each of the individual light beams 7, 8, 10 is now checked continuously or at short intervals and, if necessary, regulated in order to keep the color of the combined beam path 13 in a narrow error band. Otherwise, a color of the combined beam path 13 z. B. depending on a temperature due to a different light intensity change of the individual light beams 7,8,10 move. For this purpose, in each case a test beam 30r, 30b and 30g is coupled in the beam combination prism 29 serving as beam combination optics from the individual light beams 7, 8, 10, as described in more detail with reference to FIG. Each of the sample beams or color channels 30r, 30b, 30g passes through a respective focusing lens 31 and is imaged therefrom onto a respective photodetector in the form of a photodiode 32. The photodiode 32 does not need to be in a focal plane of the focusing lens 31. The focal length of the focusing lens 31 is dimensioned so that the surface of the photodiode 32 is illuminated to at least two-thirds with respect to those with a (1 / e ² ) criterion determined width of the sample beam 3Or, 30b or 30g. The photodiodes 32 are embedded in a vertical web projecting from the substrate (base plate) 2 of the laser projection module 11 (FIG. 1) in such a way that the front surface of the respective photodiode 32 is flush with the web. The focusing lenses 31 of the photodiodes 32 are connected to spacers (not shown) and glued to the front surface of the photodiode 32 or the land.

The photodiodes 32 are connected to the printed circuit board 28 by means of flexible printed circuit boards ("FPCBs") (not shown). The flexible circuit boards can z. B. soldered to the circuit board 28; Alternatively, the circuit board 28 is designed as a rigid flex circuit board. The laser driver or ASIC 6 is mounted on the printed circuit board 28 (eg in a QFN housing, as so-called "bare die" or as "bare die" in flip-chip technology). In addition, support capacitors may be mounted against voltage dips on the circuit board 28 for each channel. Also can be provided for each color channel switching regulator whose converted voltage is set by the driver ASIC 6. A power transistor of the switching regulator is optionally housed in the driver ASIC 6 or designed as a separate component. The green laser 10 may be electrically connected to the circuit board 28 via wire or pin bridges. The red and blue laser diodes 4, 5 can be constructed in so-called TO56 or TO38 (i-cut) packages and likewise be connected to the printed circuit board 28 by means of flexible printed circuit boards.

An electrical contacting of the laser projection module Ij can take place, for example, via a flexible printed circuit board or contact pads on the printed circuit board 28. The contact can, for example, have the following pin assignment.

With regard to the digital interface, the specified values of the transmission frequencies are to be understood as example values. From the above table, it can be seen that a higher number of pins must be provided at a transmission frequency of 260 MHz instead of 500 MHz.

Between the beam combination prism 29 and the focusing lens 31 of the red test beam 30r, there is an optical filter 33 in the red test beam 30. The red filter may alternatively also be integrated in the beam combination prism 29, e.g. On an outer front surface 36r (see FIG. 11). A sensor signal of the photodiodes 32 can then be fed back to the integrated circuit in the form of an ASIC 6 in order to adjust the light intensity of the individual beam paths or color channels 7, 8, 10 at a predetermined, e.g. B. pixel-dependent, setpoint.

11 shows a plan view of a sketch of the beam combination prism 29 of the laser projection module Ij from FIG. 10. The red, blue and green beams 7, 8 and 10 entering the beam combination prism 29 respectively strike a beam splitter 34r, 34b and 34g in the beam combination prism 29. At the beam splitter 34r, 34b, 34g, the respective input beam 7, 8, 10 is deflected 90 ° to the right into a projection light beam 35r, 35b or 35g with higher intensity, while a weaker test beam 30r, 30b or 30g is deflected forwards (in x Direction) to the focusing lens 31 of FIG. will be. At the right end, all three projection light beams 35r, 35b, 35g are collinearly output as the combined output light beam 13.

More specifically, the surfaces of the laser projection module 29 may be constituted as follows: The (red) beam splitter 34r is designed as an inner prism surface having a transmission coefficient of Ts = (2 +/- 0.3) for the beam polarized portion of the red input light beam 7 , The vast majority of the input light beam 7 is thus reflected to the right at the beam splitter 34r, the rest is transmitted as a test beam 30r. The sample beam 30r then also hits the outer front surface 36r, which is designed antireflecting, z. B. is coated with an antireflection layer, and which leaves the sample beam 30r substantially unhindered. The rear outer surface 37r is designed to be anti-reflective.

Similarly, the (blue) beam splitter 34b is configured as an inner prism surface having a transmission coefficient of Ts = (2 +/- 0.3) for the beam polarized portion of the blue input light beam 8. The by far predominant part of the blue input light beam 8 is therefore reflected to the right at the beam splitter 34b, the remainder being transmitted as a blue test beam 30b. The sample beam 30b then also hits the outer front surface 36b, which is designed antireflecting, z. B. coated with an antireflection layer, and which leaves the blue sample beam 30b substantially unhindered. For the red projection beam 35r, the blue beam splitter 34b is over 99% transmissive. This means that a small proportion of <1% of the red projection specimen beam 35r is reflected forward (in the x direction) and thus mixes with the blue specimen beam 30b within the laser projection module 29. If both color components (red and blue) were transferred to the photo-photograph taken for the blue test beam 30b If the diode is incident, the intensity or brightness measurement would be falsified by this so-called crosstalk. In order to avoid this, the front outer surface 36b of the laser projection module 29 is designed to be highly reflective of the red light. The back outer surface 37b is anti-reflective to light rays of all colors.

Similarly, the (green) beam splitter 34g is configured as an inner prism surface which has a transmission coefficient of Ts = (2 +/- 0.3) for the portion of the green input light beam 10 polarized in the beam direction. The by far predominant part of the green input light beam 8 is therefore reflected to the right at the beam splitter 34g, the remainder being let through as a green test beam 30g. The test beam 30g then also hits the outer front surface 36g, which is designed antireflecting, z. B. coated with an antireflective layer, and which leaves the green test beam 30g substantially unhindered. For the red projection beam 35r and the blue projection beam 35b, the green beam splitter 34g is over 99% transparent. That is, a small amount of <1% of the red and blue projection probes 35r and 35b are reflected forward (in the x-direction) and thus mixed within the laser projection module 29 with the green probe beam 30g. If all of the color components (red, blue and green) were to be incident on the photodiode intended for the green test beam 30b, then the intensity or brightness measurement would also be falsified by this so-called crosstalk. In order to avoid this, the front outer surface 36g of the laser projection module 29 for the red and the blue light is designed to be highly reflective. The green laser 9, which internally converts primary IR light to green light, also emits a fraction of IR light. In order to prevent IR light from significantly entering the combined beam path 13, the green beam splitter 34g is over 99% transparent to IR light. The rear outer surface 37g is antireflective for light rays of all colors. ben executed. The back outer surface 37 is thus executed independent of color antireflective. Of course, the laser projection module 29 may also be constructed differently; For example, the blue beam splitter 34b may have a transmittance for beam-polarized red light greater than 99.5%, and the green beam splitter 34g may have a transmissivity for beam-polarized red and blue light greater than 99.5%.

FIG. 12 shows a plan view of a sketch of a laser projection module Ik according to an eleventh embodiment. In contrast to the laser projection module Ij of the tenth embodiment, the red test beam 3Or and the blue test beam 30b run within the respective LD package 4b, 5b, where the respective photosensor 32 and - in the case of the red test beam 30r the filter 33 - are located. In particular, in the case of the laser diodes 4 and 5, use is made of the fact that the respective LED chip 4a, 4b also emits an edge emitter to the rear (opposite to the x direction). As a result, the photodiodes 32 in the LD package 4b, 5b can be arranged rearwardly of the respective laser chip 4a, 5a without beam splitters, and likewise the filter 33 in the red test beam 30r. The photodiodes 32 may be arranged in the laser package 4b, 5b close to the back facets of the laser chips 4a, 5a. Optionally, a beam deflection can be implemented in the package 4b, 5b. The filter 33 may be configured as a transmission or reflection filter. With respect to the green light beam 10, between the green laser 9 and the collimating lens 11, there is a beam splitter 38 which obliquely reflects the weak green test beam 30g onto a photodiode 32g attached to an outside of the laser 9. The photodiode 32g may alternatively be supported by a separate device. The electrical contacting of the photodiode 32g is effected by means of a flexible printed circuit board ("FPCB") with the printed circuit board 28. To protect against scattered radiation, a mechanical diaphragm can be installed in front of the photodiode 32g. This embodiment results in a particularly compact and easy to construct design.

The lasers of the embodiments described above may be designed so that the laser 4 red light with a

Wavelength of 440nm 645 nm +/- 10 nm emitted, the laser 5 blue light emitted with a wavelength of 440 nm +/- 10 nm and the green laser 9 light with a wavelength of 530 nm +/- 10 nm and IR light emitted at a wavelength of 1055 nm +/- 10 nm.

Of course, the present invention is not limited to the embodiments shown.

As an alternative to using an aluminum nitride ceramic, any other substrate may be used, for example another solid substrate or also a printed circuit board. For example, other ceramics such as AL2O3 may also be used as the base material of the substrate. In this case, the invention is not limited to a ceramic solid substrate, but it is also possible, for example, to use ceramic layer bodies, such as LTCC ceramic layer bodies. Also, instead of a ceramic, metals are usable as a substrate material, for example, copper, aluminum, etc., singly or in combination.

Furthermore, the invention is not limited to the use of lasers, but may also include other types of light sources, such as light-emitting diodes. Also, the invention is not limited to the use of laser diodes as laser sources, but also all other types of lasers can be used. In addition to an ASIC, any other type of integrated circuit may be used, such as a microprocessor, an FPGA, etc.

In general, the features of the different embodiments can also be combined. For example can the laser projection modules of FIG 6 to FIG 10 and FIG 12 are configured without beam combination, z. B. similar to the laser projection module according to FIG 3. In this case, the module emits three parallel light beams of different colors. It is also possible a different geometric arrangement of the laser; Thus, a beam direction of the radiation emitted by the red and the blue laser diode (s) may be perpendicular to the beam exit direction of the green laser. This results in a higher flexibility in customer design-in.

In general, the integrated circuit as a single chip, in particular ASIC, or as -. B. hybrid - be executed arrangement of multiple chips.

Also, the red laser and the blue laser, possibly with photodiodes and / or filters, can be accommodated in a common package. Additionally or alternatively, the photodiode of the green feedback channel or probe beam may be integrated into the green laser package. As a result, very compact arrangements are possible. An even smaller design results in the integration of all lasers and possibly photodiodes and filters in a single housing

Reference sign list

1 laser projection module

2 substrate 3 front side of the substrate

4 red laser diode

5 blue laser diode

6 integrated circuit

7 Beam path of the red laser diode 8 Beam path of the blue laser diode

9 green OPS laser

10 beam path of the green OPS laser

11 lens

12 beam combination optics 13 combined beam path

14 reflection surface of the beam combination optics

15 imaging element

16 power level

17 digital interface 18 connectors

19 plugs

20 digital interface

21 signal conditioning part

22 video pre-processing unit 23 video memory

24 mechanical stop

25 trace 26 bonding wire 27 contact pad 28 printed circuit board

29 beam combination prism

30 sample beam

31 focusing lens

32 photodiode 33 filter

34 beam splitter

35 projection light beam Front surface of the beam combination prism Back outer surface of the beam combination prism Beam splitter

Claims

claims

1. projection module (Ia-Ik), comprising at least one semiconductor light source (4,5,9) and at least one integrated circuit (6; 16,17; 21-23) which are arranged on a common substrate (2).

Second projection module (Ia-Ik) according to claim 1, wherein the substrate (2) is a ceramic body.

3. Projection module (Ia-Ih, Ij, Ik) according to claim 1 or 2, wherein the at least one semiconductor light source comprises at least two semiconductor light sources (4,5,9), wherein main beam directions (7,8,10) of the semiconductor light sources (4,5,9) emitted light beams are collinear.

4. Projection module (Ia-Ih, Ij, Ik) according to claim 4, wherein the main beam directions (7,8,10) not more than 5 mrad, especially not more than 3 mrad, differ from each other.

5. Projection module (Ia-Ih, Ij, Ik) according to one of the preceding claims, in which at least one optical element (11; 12) is arranged on the substrate (2), wherein the optical element (11; one of the light beams, which are emitted from the at least one semiconductor light source (4,5,9), is arranged and arranged.

6. Projection module (Ic-Ih, Ij, Ik) according to claim 5, wherein the at least one optical element (11; 12) at least one beam-forming optical system (11), wherein each of the at least one semiconductor light source is optically downstream of a beam-forming optical system (11) ,

7. Projection module (Id-Ih; Ij, Ik) according to claim 3 or 4 in combination with one of claims 5 or 6, wherein the at least one optical element (11, 12) has at least one beam combination optics (12) for combining the light beams emitted by the at least two semiconductor light sources (4, 5, 9).

8. Projection module (Ie-Ih, Ij, Ik) according to one of the preceding claims, wherein on the substrate (2) at least one imaging element (15) in a combined beam path (13) of the at least one semiconductor light source (4,5 , 9) is arranged.

9. The projection module (If-Ih) according to one of the preceding claims, wherein the at least one integrated circuit (6; 16, 17; 21-23) comprises at least one digital or mixed integrated circuit (17) and at least one analog integrated circuit (16), wherein the analog integrated circuit (16) of a semiconductor light source (4,5,9) is connected upstream of the drive and the digital or mixed integrated circuit (17) of the analog integrated circuit (16) is connected upstream as a digital interface.

10. The projection module (Ig-Ih) according to claim 9, wherein the at least one integrated circuit (6; 16, 17; 21-23) has at least one integrated circuit (21) for signal conditioning, each of which is a digital or mixed integrated one Circuit (20) and an analog integrated circuit (16) is interposed.

A projection module (Ih) according to claim 9 or 10, wherein the at least one integrated circuit (6; 16, 17; 21-23) comprises at least one image processing integrated circuit (22) corresponding to the digital or mixed integrated circuit (20 ) is connected upstream.

12. Projection module (Ie-Ih, Ij, Ik) according to one of the preceding claims, in which the at least one semiconductor light source has at least one laser diode (4, 5).

The projection module (Ia-Ih; Ik; Ik) according to one of claims 3 or 4 in combination with claim 11, wherein the at least one semiconductor light source comprises at least one red laser diode (4), one blue laser diode (5) and one green frequency doubling OPS -Laser (9).

14. Projection module (Ie-Ih, Ij, Ik) according to one of the preceding claims, wherein at least one beam path (7, 8, 10) of at least one of the semiconductor light sources

(4,5,9) a test beam (30r, 30b, 30g) is coupled out and a respective light sensor (32) is supplied.

15. A portable projection device, comprising at least one projection module (Ia-Ii) according to one of the preceding claims.