Laser projection imaging device

Abstract

The embodiment of the invention provides a laser projection imaging device, and relates to the technical field of laser projection. The laser projection imaging device comprises a VCSEL-based area array light source which comprises a driving circuit and pixel units arranged in an array, each pixel unit comprises a first light-emitting unit, a second light-emitting unit and a third light-emitting unit, the first light-emitting unit emits red laser, the second light-emitting unit emits green laser, and the third light-emitting unit emits blue laser; the driving circuit is electrically connected with the first light-emitting unit, the second light-emitting unit and the third light-emitting unit, and is configured to drive the corresponding light-emitting unit based on an electric addressing mode to enable the area array light source to emit a target image; the micro-lens area array is positioned on the light-emitting side of the area array light source and is configured to homogenize light spots of the light-emitting units; the imaging lens is located on the side, away from the area array light source, of the micro-lens array and used for receiving the light beams passing through the micro-lens area array and conducting projection imaging. Therefore, the cost of the laser projection imaging device is reduced, and the size of the laser projection imaging device is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of projection imaging technology, and more specifically, to a laser projection imaging device. Background Art

[0002] Compared to the LED (Light Emitting Diode) and blue laser-excited phosphor light sources used in traditional projection TVs, laser light sources are highly efficient, addressing the low electro-optical efficiency of LEDs, the low conversion efficiency of blue laser-excited phosphors, poor heat dissipation characteristics, and the difficulty in applying them to large-scale projections. Laser display technology, which supports laser light sources, offers advantages such as excellent monochromaticity, a wide color gamut, long life, high brightness, and low power consumption, leading to its widespread adoption.

[0003] Related laser display technologies generally adopt a three-color laser display solution. The laser light source is generally an edge emitting laser (EEL), and the related technology requires the use of a spatial light modulator called a digital micro-mirror device (DMD).

[0004] The DMD used in the related art is monopolized by a small number of technology manufacturers, and has a high cost. In addition, the characteristics of the DMD will result in a decrease in the utilization rate of the laser light source beam. On the other hand, the EEL used in the related art also has the problem of low beam utilization of the overall optical path structure due to its characteristics, and the use of other devices to reduce speckle leads to a large volume of the overall optical path structure. Summary of the Invention

[0005] The exemplary embodiments of the present application provide a laser projection imaging device for solving at least some of the problems of large size, low cost, low beam utilization, and speckle.

[0006] The technical solutions provided by the embodiments of this application are as follows:

[0007] In a first aspect, an embodiment of the present application provides a laser projection imaging device, comprising:

[0008] A VCSEL (Vertical-Cavity Surface-Emitting Laser) array light source includes a drive circuit and arrayed pixel units, wherein the pixel units include a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit, wherein the first light-emitting unit emits red laser light, the second light-emitting unit emits green laser light, and the third light-emitting unit emits blue laser light; the drive circuit is electrically connected to the first light-emitting unit, the second light-emitting unit, and the third light-emitting unit, and is configured to drive the corresponding light-emitting units based on an electrical addressing method, so that the array light source emits a target image;

[0009] A microlens array, located on the light-emitting side of the array light source, configured at least to homogenize the light spot of the corresponding light-emitting unit;

[0010] The imaging lens is located on a side of the microlens array away from the area array light source along the propagation direction of the light beam, and is configured to receive the light beam after passing through the microlens area array and project an image.

[0011] It can be seen from the above technical solution that the laser projection imaging device provided in the embodiment of the present application uses a VCSEL array as a laser light source. The resulting laser projection imaging device no longer requires a DMD, thereby improving the utilization rate of the laser beam. In addition, the cost of VCSEL is relatively low, thereby reducing the overall cost of the laser projection imaging device. Compared with EEL, VCSEL has unique advantages as a laser light source. Its output beam is a circularly symmetrical Gaussian beam with a small beam divergence angle, good beam quality, easy beam shaping, and high coupling efficiency. The lateral size can reach several to tens of microns, which is small and easy to manufacture large-scale high-density monolithic integrated two-dimensional arrays. The number of arrays can be increased to improve power output and obtain larger and brighter projection images. The active area is small, the working threshold is low, the energy consumption is low, and the electro-optical conversion efficiency is high. Moreover, the phase relationship between the light-emitting units of the VCSEL array is not fixed, its coherence is weak, and a monolithic VCSEL array with equal wavelength intervals can be made, which is conducive to reducing the beam coherence of the device, weakening speckle, and improving the output quality of the projection picture. It is no longer necessary to set up specific other devices to reduce speckle, thereby reducing the volume of the overall laser projection imaging device. In summary, the technical solution provided by the present application can reduce the cost of the laser projection imaging device and reduce the volume of the laser projection imaging device while ensuring imaging quality and weakening speckle. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the implementation methods in the embodiments of the present application or related technologies, the following is a brief introduction to the drawings required for use in the embodiments or related technology descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0013] Figure 1 Schematic diagram of the optical path structure of a three-color laser display in the related art;

[0014] Figure 2 Schematic diagram of the structure of an edge-emitting laser in the related art;

[0015] Figure 3 A schematic structural diagram of a laser projection imaging device provided for one or more embodiments of the present application;

[0016] Figure 4 A schematic diagram of a VCSEL structure provided for one or more embodiments of the present application;

[0017] Figure 5 A schematic diagram of the structure of a driving circuit 311 and a light-emitting unit provided in one or more embodiments of the present application;

[0018] Figure 6 A schematic diagram of another structure of a driving circuit 311 and a light-emitting unit provided in one or more embodiments of the present application;

[0019] Figure 7 A schematic diagram of a curve showing the relationship between luminous intensity and target operating current provided in one or more embodiments of the present application;

[0020] Figure 8 A current pulse schematic diagram provided for one or more embodiments of the present application;

[0021] Figure 9 Another current pulse schematic diagram provided for one or more embodiments of the present application;

[0022] Figure 10 A schematic diagram of a pixel unit arrangement provided for one or more embodiments of the present application;

[0023] Figure 11 A schematic diagram of another pixel unit arrangement provided for one or more embodiments of the present application;

[0024] Figure 12 A schematic diagram of another pixel unit arrangement provided for one or more embodiments of the present application;

[0025] Figure 13 A schematic diagram of a planar array light source structure provided by one or more embodiments of the present application;

[0026] Figure 14 A schematic diagram of another area array light source structure provided for one or more embodiments of the present application;

[0027] Figure 15 A schematic diagram of another area array light source structure provided for one or more embodiments of the present application;

[0028] Figure 16 A schematic diagram of a light-emitting chip structure provided for one or more embodiments of the present application;

[0029] Figure 17 A schematic diagram of a microlens array structure provided for one or more embodiments of the present application;

[0030] Figure 18 A schematic diagram of an application scenario of a microlens array provided for one or more embodiments of the present application;

[0031] Figure 19 A schematic diagram of another application scenario of a microlens array provided for one or more embodiments of the present application;

[0032] Figure 20 A schematic diagram of another application scenario of a microlens array provided for one or more embodiments of the present application;

[0033] Figure 21 A schematic diagram of a substrate structure provided for one or more embodiments of the present application;

[0034] Figure 22 A schematic diagram of a computer controller connection method provided for one or more embodiments of the present application;

[0035] Figure 23 A schematic structural diagram of another laser projection imaging device provided for one or more embodiments of the present application;

[0036] Figure 24 A schematic diagram of a receiving screen structure provided for applying for one or more embodiments;

[0037] Figure 25 Schematic diagram of application scenarios of the laser projection imaging device provided in one or more embodiments of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose and implementation of this application clearer, the exemplary implementation of this application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only part of the embodiments of this application, not all of the embodiments.

[0039] It should be noted that the brief descriptions of terms in this application are only for the purpose of facilitating the understanding of the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their ordinary and usual meanings.

[0040] The terms "comprise," "include," and "have," and any variations thereof, are intended to cover but not exclude inclusion; for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0041] Figure 1 Schematic diagram of the three-color laser display optical path structure in the related art; Figure 1 As shown, in the three-color laser display solution of the related art, the laser light source of the laser display uses a multi-chip three-color laser to emit a green laser beam 100, a blue laser beam 200, and a red laser beam 300. The green laser beam 100 is reflected by the green light reflector 101 and projected through the blue dichroic plate 102 and the red dichroic plate 103. The blue laser beam 200 is reflected by the blue dichroic plate 102 and projected through the red dichroic plate 103. After the red laser beam 300 is reflected by the red dichroic plate 103, the laser beam reaches the diffuser 104, is homogenized by the diffuser 104, and reaches the lens group 105. After being converged by the first lens group 105, the laser beam enters the optical machine light guide 106. After passing through the light guide 106, the laser beam reaches the second lens group 107. After being reflected and refracted by multiple second lens groups 107, the laser beam enters the TIR (Total Internal Reflection) The laser beam is totally reflected by the TIR prism 108, converged and focused onto the surface of the digital micro-mirror device (DMD) 109. The laser beam reflected by the DMD 109 directly penetrates the TIR prism 108 and enters the projection lens 110, and is then magnified by the projection lens 110 and formed on the screen.

[0042] In this structure, DMD109, a spatial light modulator, is the primary display element in Digital Light Processing (DLP) display technology. It typically consists of an array of thousands of tiny, highly reflective aluminum micromirrors fabricated using semiconductor technology. Each reflective micromirror corresponds to a pixel. Under digital signal control, it achieves a ±12° deflection, reflecting the incoming laser beam toward projection lens 110. Laser beams that do not enter projection lens 110 are absorbed, reducing laser beam utilization. DMD109 is monopolized by certain technology manufacturers and is expensive. Because TIR prism 108 is located very close to DMD109, it can easily generate stray light, affecting image contrast.

[0043] This structure uses optical addressing. Generally, optical addressing involves first using a spatial light modulator (SLM), such as the DMD mentioned above, to convert the corresponding write optical signal into a spatial charge distribution, refractive index distribution, and other parameters. This is then modulated using various effects (electro-optical, birefringence, etc.) to read out the optical signal. Corresponding structures include liquid crystal light valves and cathode ray tube liquid crystal light valves. The need for devices such as a spatial light modulator makes the overall structure of the laser display optical path complex and bulky, making it difficult to miniaturize.

[0044] Figure 2 FIG. 1 is a schematic diagram of the structure of an edge-emitting laser in the related art; FIG. Figure 2 As shown, the conical shape in the figure represents a laser beam. In the related art, the laser light source for laser displays is generally an EEL. Due to the good monochromaticity of laser light, its coherence is high. Scattered by the rough surfaces of the optical components in the laser display optical path structure and affected by subtle irregularities on the display screen surface, the laser beam becomes highly coherent in time and space, generating a large amount of interference fringes and speckle noise, which seriously affects the image quality and viewer experience. Therefore, to reduce the impact of speckle, the related art often incorporates a rotating diffuser or diffuser wheel device (such as diffuser 104) into the optical path system. However, the addition of a rotating diffuser or diffuser wheel device reduces light energy utilization, resulting in poor display quality. It also increases the overall system volume of the optical path structure, hindering miniaturization. Furthermore, the spot corresponding to the beam emitted by the EEL is elliptical. Since the elliptical light needs to be shaped into a circular Gaussian spot, corresponding optical elements are also required for beam shaping. The inclusion of such optical elements also complicates the overall structure of the optical path system and increases its volume, hindering miniaturization.

[0045] To address at least some of the above technical issues, the present application provides a laser projection imaging device. Figure 3 A schematic structural diagram of a laser projection imaging device provided for one or more embodiments of the present application. The present application adopts micro semiconductor laser panel (Micro Laser Diode Panel, MLDP) technology and a VCSEL-based array light source 31 as a laser light source. At the same time, a microlens array 32 is provided on the light-emitting side of the array light source 31 to homogenize the light spot for each light-emitting unit in the array light source 31. An imaging lens 33 is provided on the side of the microlens array 32 away from the array light source 31 to receive the light beam and project the image.

[0046] Figure 4A schematic diagram of a VCSEL structure is provided for one or more embodiments of the present application. The conical shape in the figure represents a laser beam. Compared to EELs, VCSELs have unique advantages as laser light sources. Specifically, the output beam of a VCSEL is a circularly symmetrical Gaussian beam with a small beam divergence angle, good beam quality, easy beam shaping, and high coupling efficiency. The lateral size can reach several to tens of microns, which is small and easy to manufacture into a large, high-density, monolithically integrated, two-dimensional array light source 31. The number of arrays can be increased to improve power output and obtain larger and brighter projected images. The active area is small, the operating threshold is low, the energy consumption is low, and the electro-optical conversion efficiency is high.

[0047] Furthermore, the phase relationship between the light-emitting units in a VCSEL-based area array light source can be flexible, resulting in weak coherence and the ability to create a single-piece area array light source with equal wavelength intervals. This helps reduce the device's beam coherence, mitigates speckle, and improves the quality of the projected image output. There's no need to configure specific other devices to reduce speckle, thereby reducing the overall size of the laser projection imaging device. Taking a 0.47-inch DMD as an example, it may have 2.07 million micromirrors, projecting 1920*1080 pixels. Each pixel unit is 312 at 5.4μm. Using VCSELs as light-emitting units, their size can be ≤5μm. Therefore, using VCSELs as the light-emitting units in the Micro-LD Panel area array can achieve higher resolution and further reduce the size of the overall optical system. By comparing with related solutions, the embodiment of the present application can reduce the use of multiple lens groups, greatly compress the optical path volume, and improve the utilization rate of light energy. Since the array light source 31 integrates R, G, and B three-color light sources, it avoids the pixel alignment problem caused by the multi-MicroLaser Diode Panel array and can simplify the system structure.

[0048] Continue reading Figure 3 In some embodiments, the area array light source 31 may include a driving circuit 311 and array-arranged pixel units 312, the pixel units 312 include a first light-emitting unit 3121, a second light-emitting unit 3122, and a third light-emitting unit 3123, the first light-emitting unit 3121 emits red laser, the second light-emitting unit 3122 emits green laser, and the third light-emitting unit 3123 emits blue laser; the driving circuit 311 is electrically connected to the first light-emitting unit 3121, the second light-emitting unit 3122, and the third light-emitting unit 3123, and is configured to drive the corresponding light-emitting units based on an electrical addressing method, so that the area array light source 31 emits a target image.

[0049] Specifically, the present application uses an electrical addressing method to drive the light-emitting units. The electrical addressing method typically uses a video signal or a computer level signal to control the complex transmittance of the spatial light modulator. This method applies the signal to the corresponding light-emitting unit through scanning via the electrodes on the spatial light modulator. In the embodiment of the present application, the light-emitting units are driven by electrical addressing, which can control the light-emitting units to emit light of the target color and brightness, allowing the entire array light source 31 to emit the target image. This saves components corresponding to the optical addressing modulation, helps reduce the overall volume, and facilitates a miniaturized design.

[0050] Exemplarily, the driver circuit 311 may be a CMOS driver circuit 311. Addressing of the driver circuit 311 is achieved by controlling the desired driver state by setting a signal input to a high level (ON) or a low level (OFF), thereby achieving pixel addressing. The addressing method is similar to the individual addressing of a Micro-LED display. The driver circuit 311 can drive a specific light-emitting unit to emit light based on electrical addressing. For example, the area array light source 31 may include multiple pixel units 312. For each pixel unit 312, the color, brightness, and duration of the display of the pixel unit 312 are controlled based on the image to be displayed. More specifically, a specific light-emitting unit in each pixel unit 312 can be controlled to emit color light of a specific brightness and for a specific duration. For example, the first light-emitting unit 3121 in a pixel unit 312 can be controlled to emit a red laser of a specific brightness and for a specific duration, while the second light-emitting unit 3122 and the third light-emitting unit 3123 in the pixel unit 312 are controlled not to emit light. After the laser beam emitted by pixel unit 312 passes through microlens array 32, it can be homogenized, i.e., a uniform light spot. The homogenized light spot passes through imaging lens 33, which can project an image based on the received light spot, for example, by projecting the projected light onto receiving screen 2401, so that the user can view the corresponding image. This application utilizes CMOS driver circuit 311 to control and form an image at the light source, and projects it onto the screen through imaging lens 33, which facilitates miniaturized system integration and can reduce costs.

[0051] Figure 5 A schematic diagram of a driving circuit 311 and a light-emitting unit structure provided for one or more embodiments of the present application; in some embodiments, the number of driving circuits 311 for a single pixel unit 312 can be multiple, for example, the number of driving circuits 311 can be equal to the number of light-emitting units in the pixel unit 312, and each driving circuit 311 is electrically connected to a light-emitting unit and controls a corresponding light-emitting unit. For example, Figure 5The driving circuit is shown as a first driving circuit 51. In this case, the first driving circuit 51 can also be arranged in an array similar to the light-emitting units in the pixel unit 312. When controlling the light-emitting units to emit laser light of a specific color, each first driving circuit 51 controls only one light-emitting unit to emit light. Thus, each driving circuit 311 can control a light-emitting unit, making the control of the light-emitting units more flexible.

[0052] Figure 6 This is another schematic diagram of a driving circuit 311 and a light-emitting unit structure provided in one or more embodiments of the present application; in some embodiments, the driving circuit 311 can achieve multi-channel output. For example, Figure 6 The driving circuit is shown as a second driving circuit 61. The second driving circuit 61 can be set in a one-to-one correspondence with the pixel unit 312. The output end of a single second driving circuit 61 is respectively connected to the first light-emitting unit 3121, the second light-emitting unit 3122, and the third light-emitting unit 3123 corresponding to the same pixel unit 312. In this case, the number of first driving circuits 51 can also be multiple, and they can also be arranged in an array, and can be similar to the array arrangement of the pixel unit 312, so as to facilitate the electrical connection between the driving circuit and the light-emitting unit in the corresponding pixel unit and simplify the circuit connection structure. In the embodiment of the present application, a single second driving circuit 61 can control the emission of multiple light-emitting units in the corresponding pixel unit 312, thereby reducing the number of driving circuits 311.

[0053] In some embodiments, in order to make the light-emitting unit emit a specific brightness and a specific color, the driving circuit 311 can apply a target operating current and / or a target modulation pulse width to the corresponding light-emitting unit; more specifically, the target operating current can be used to control the brightness of the light-emitting unit, and the target modulation pulse width can be used to control the grayscale of the light-emitting unit.

[0054] Within the working range of the VCSEL-based area array light source light unit, the relationship between its luminous intensity and the target working current can be expressed by the LI curve. Figure 7 A schematic diagram of a relationship curve between luminous intensity and target operating current provided in one or more embodiments of the present application, wherein the horizontal axis I represents the current intensity and the vertical axis L represents the luminous intensity; Figure 7 As the injected current increases, the luminous intensity also increases. When the luminous intensity reaches saturation, it no longer increases significantly with increasing injected current. The modulation characteristics of the area array light source can be achieved by applying different currents and pulse widths to the light-emitting units. By adjusting the target operating current and driving time of the light-emitting units, the brightness can be changed, thereby presenting different brightness levels of light and dark images.

[0055] Figure 8A current pulse schematic diagram is provided for one or more embodiments of the present application, wherein the horizontal axis represents time and the vertical axis represents current. For example, the current intensity in the T1-T2 time period is a, the current intensity in the T3-T4 time period is b, and a<b. When a certain light-emitting unit is controlled in this current pulse manner, the brightness of the light-emitting unit in the time period corresponding to T1-T2 is less than the brightness of the light-emitting unit in the time period corresponding to T3-T4. In this embodiment, only the same light-emitting unit is illustrated. The same is true for different light-emitting units. For example, current pulses of different current intensities can be input to different light-emitting units in the same time period, thereby making the brightness of different light-emitting units different. The pulse width can be divided into multiple levels, and different levels represent different grayscale information. By controlling the exposure duty cycle of each light-emitting unit pixel, each light-emitting unit can achieve a different grayscale level to achieve a modulation effect on the image grayscale.

[0056] Figure 9 Another current pulse schematic diagram provided for one or more embodiments of the present application, wherein the horizontal axis represents time and the vertical axis represents current. The exposure duty cycle can be calculated as D = P / N, where D represents the exposure duty cycle, P represents the duration of non-zero current intensity in one or more time periods, N represents the duration of zero current intensity in one or more time periods, and P + N = 100. The relationship between grayscale and exposure duty cycle can satisfy G = P / (P+N) × 100%, where G represents grayscale. Further, P / N = G / (1-G). For example, the duration of the time period corresponding to T1-T2 is t1, the duration of the time period corresponding to T2-T3 is t2, the duration of the time period corresponding to T4-T5 is t3, and the duration of the time period corresponding to T5-T6 is t4, and t1>t3, (t1÷t2)≠(t3÷t4), that is, the current pulse width is different and the exposure duty cycle is also different. If a light-emitting unit is controlled in this current pulse manner, the grayscale in the time period corresponding to T1-T3 is different from the grayscale and brightness in the time period corresponding to T4-T6. For example, when displaying a pure white screen, the exposure duty cycle in one or more time periods can be 100 / 0. Conversely, when displaying a pure black screen, the exposure duty cycle in one or more time periods can be 0 / 100.

[0057] In some embodiments, the image displayed by each pixel unit 312 is composed of three primary colors: red (R), green (G), and blue (B). Within an image frame period, to achieve white balance, the three RGB primary colors are displayed for different percentages. The sum of the percentages of these three primary colors is 100%. The grayscale of each pixel unit 312 can be the sum of the percentages of the three RGB primary colors, i.e., G = TR × GR + TG × GG + TB × GB, where TR represents the percentage of the period during which red light is displayed to achieve white balance within the image frame period, TG represents the percentage of the period during which green light is displayed to achieve white balance within the image frame period, and TB represents the percentage of the period during which blue light is displayed to achieve white balance within the image frame period. GR represents the grayscale of red, GG represents the grayscale of green, and GB represents the grayscale of blue. To achieve a certain white balance requirement, within an image frame period, the percentages of the red, green, and blue periods can meet the requirements of 50% for red, 20% for green, and 30% for blue.

[0058] In some embodiments, each pixel unit 312 can be composed of a 2×2 light-emitting unit array; in some implementations, the luminous efficiency of light-emitting units of different colors is different. In order to achieve ideal brightness effects, color saturation, color uniformity, etc., each pixel unit 312 can be composed of two light-emitting units of the same color and two light-emitting units of different colors. The two light-emitting units of the same color can be the target light-emitting units.

[0059] Figure 10 A schematic diagram of an arrangement of pixel units 312 provided in one or more embodiments of the present application is shown. Figure 11 A schematic diagram of another arrangement of pixel units 312 provided in one or more embodiments of the present application is shown. Figure 12 This is a schematic diagram of another arrangement of pixel units 312 provided in one or more embodiments of the present application, see Figure 10-12 Each pixel unit 312 may include a first light emitting unit 3121, a second light emitting unit 3122 and a third light emitting unit 3123. Figure 10 The first light emitting unit 3121 is set as the target light emitting unit, that is, the number of the first light emitting units 3121 is two, and they are arranged in a diagonal manner, the second light emitting unit 3122 and the third light emitting unit 3123 are one each, and the second light emitting unit 3122 and the third light emitting unit 3123 are also arranged in a diagonal manner; for example Figure 11 The second light emitting unit 3122 is set as the target light emitting unit, that is, the number of the second light emitting units 3122 is two, and they are arranged in a diagonal manner, and the first light emitting unit 3121 and the third light emitting unit 3123 are one each, and the first light emitting unit 3121 and the third light emitting unit 3123 are also arranged in a diagonal manner; for example Figure 12 In the example, the third light-emitting unit 3123 is set as the target light-emitting unit, that is, there are two third light-emitting units 3123, and they are arranged diagonally. There is one first light-emitting unit 3121 and one second light-emitting unit 3122, and the first light-emitting unit 3121 and the second light-emitting unit 3122 are also arranged diagonally. Thus, different light-emitting unit arrangements can be set based on different needs to achieve brightness, color saturation, and color uniformity that meet the target projection display requirements.

[0060] More specifically, the area array light source 31 may include a plurality of pixel units 312 , and each pixel unit 312 may include a plurality of light-emitting units.

[0061] Figure 13 This is a schematic structural diagram of a planar array light source 31 provided in one or more embodiments of the present application. Figure 14 This is a schematic structural diagram of another planar array light source 31 provided in one or more embodiments of the present application. Figure 15 This is a schematic diagram of another structural example of a planar array light source 31 provided in one or more embodiments of the present application. Figure 13 , Figure 13 The above-mentioned Figure 10 The area array light source 31 is composed of the pixel units 312, Figure 14 The above-mentioned Figure 11 The area array light source 31 is composed of the pixel units 312, Figure 15 The above-mentioned Figure 12 The area array light source 31 composed of the pixel units 312 in Figure 13-15 In the embodiment, the light emitting units are arranged in an array along a first direction and a second direction, and along the first direction and / or the second direction, the colors of the lasers emitted by two adjacent light emitting units are different.

[0062] It should be noted that Figure 13-15 It only illustrates the case where the colors of the laser beams emitted by two adjacent light-emitting units in the first direction and the second direction are different. However, it is obvious that in some possible embodiments, in the first direction or the second direction, there may be a case where the laser beams emitted by two adjacent light-emitting units have the same color, which is not illustrated here. The first direction and the second direction can be simply understood as the horizontal direction and the vertical direction, that is, the first direction and the second direction can be perpendicular to each other, and a rectangular matrix is ​​formed between every four light-emitting units. It should be understood that this is only an exemplary description, and it does not limit the first direction and the second direction to be perpendicular to each other. For example, in some possible embodiments, the first direction and the second direction may only intersect, but not be perpendicular to each other, and a rectangular matrix cannot be formed between every four light-emitting units, such as a parallelogram matrix.

[0063] Figure 16 A schematic diagram of a light-emitting chip structure provided for one or more embodiments of the present application; in some embodiments, the first light-emitting unit 3121 may include a first light-emitting chip 1601 based on a gallium arsenide substrate, and the laser wavelength of the first light-emitting chip 1601 is within 630 nanometers to 650 nanometers; the emitted laser wavelengths of different first light-emitting chips 1601 are arranged at equal intervals; the second light-emitting unit 3122 may include a second light-emitting chip 1602 based on a gallium nitride substrate, and the laser wavelength of the second light-emitting chip 1602 is within 515 nanometers to 540 nanometers; the emitted laser wavelengths of different second light-emitting chips 1602 are arranged at equal intervals; the third light-emitting unit 3123 may include a third light-emitting chip 1603 based on a gallium nitride substrate, and the laser wavelength of the third light-emitting chip 1603 is within 440 nanometers to 480 nanometers; the emitted laser wavelengths of different third light-emitting chips 1603 are arranged at equal intervals.

[0064] Taking the first light emitting unit 3121 as an example, Figure 16 The four first light-emitting units 3121 shown in the figure each include a first light-emitting chip 1601. The first light-emitting chips 1601 may be 16011, 16012, 16013, and 16014, respectively. The red laser wavelength emitted by 16011 may be 630 nm (nanometers), the red laser wavelength emitted by 16012 may be 635 nm, the red laser wavelength emitted by 16013 may be 640 nm, and the red laser wavelength emitted by 16014 may be 645 nm. In other words, the wavelengths of the laser beams emitted by different first light-emitting chips 1601 are arranged at equal intervals. This arrangement can reduce the coherence of the laser beams emitted by different light-emitting chips, weaken speckle, and improve the final image quality. In some embodiments, the wavelength interval between the laser beams emitted by different light-emitting chips may be between 3 and 5 nm. In some embodiments, the array light source 31 may include multiple light-emitting chips (here referring to light-emitting chips of the same type, for example, the same first light-emitting chip 1601), and different equally spaced arrangements may be set. For example, for the first light-emitting chip 1601 arranged in an array, the arrangement of the wavelength of the emitted laser along the first direction may be 630nm, 635nm, 640nm, 645nm, 640nm, 635nm, 630nm, 635nm, 640nm..., or 630nm, 635nm, 640nm, 645nm, 630nm, 635nm, 640nm, 645nm... and so on.

[0065] Continue reading Figure 3 The laser projection imaging device in the embodiment of the present application may further include a microlens array 32. The main function of the microlens array 1701 has been briefly described in the above embodiment. Figure 17 , Figure 17This is a schematic diagram of the structure of a microlens array 32 provided in one or more embodiments of the present application. The microlens array 32 may include microlenses 1701 arranged in an array, and the microlenses 1701 are provided in a one-to-one correspondence with the light-emitting units. In the embodiment of the present application, the microlenses 1701 can be used to homogenize the light beams emitted by the corresponding light-emitting units, and the microlens array 32 does not change the target image distribution emitted by the array light source 31. Figure 17 A preset spacing exists between the microlens array 32 and the imaging lens 33. The microlens array 32 is also used to narrow the beam divergence angle, expand the beam divergence angle, or maintain a collimated beam for the optical etendue of the imaging lens 33. The beam, after passing through the microlens array 32, is irradiated onto the light receiving surface of the imaging lens 33. More specifically, the laser beam emitted by the array light source 31 is primarily a Gaussian spot, with its beam energy primarily concentrated in the center. In addition, to improve the optical etendue of the imaging image, the beam emitted by the array light source 31 needs to be processed. Depending on the optical etendue of the optical imaging lens 33, the divergence angle of the imaging beam can be controlled to be between 8° and 11°, with different light-emitting units having different divergence angles. Figure 18 This is a schematic diagram of an application scenario of a micro-lens array 32 provided in one or more embodiments of the present application, see Figure 18 For a light emitting unit array with a large angle (e.g., a divergence angle between 12 and 22 degrees), the microlens array 32 can be used to homogenize the light spot and shrink the beam divergence angle; Figure 19 A schematic diagram of another application scenario of the microlens array 32 provided in one or more embodiments of the present application is provided in FIG. Figure 19 For a light emitting unit array with a small angle (e.g., a divergence angle between 6° and 10°), the microlens array 32 can be used to homogenize the light spot and expand the beam divergence angle; Figure 20 A schematic diagram of another application scenario of the microlens array 32 provided in one or more embodiments of the present application is provided in FIG. Figure 20 For a light emitting unit array with a divergence angle between 10° and 12°, the microlens array 32 can only be used to collimate the light beam and homogenize the light beam.

[0066] Compared to EEL collimating lenses, the microlens array 32 is easy to manufacture and has a simple structure. Furthermore, because the output beam from the array light source 31 is a Gaussian circular spot, the collimation effect is superior. Since the red, green, and blue light-emitting units are made of different materials and have different luminous properties, the surface curvature and structure of the microlenses 1701 can also vary for different light-emitting units. However, the function of microlenses 1701 with different surface curvatures and structures is to homogenize and shape the light spots into the same size (same imaging aspect ratio). Microlenses 1701 can be made of one or more materials such as sapphire, glass, or resin, using techniques such as high-temperature reflow, self-assembly, molding / imprinting / stamping, grayscale mask lithography, or dry etching pattern transfer.

[0067] Furthermore, the etendue between the image formed by the area array light source 31 and the imaging lens 33 must match. According to imaging optics theory, if the distance between the area array light source 31 and the imaging lens 33 is relatively large, an image beam reducer should be used near the area array light source 31 to ensure that the image matches the imaging lens 33. Conversely, an image beam expander should be used. During design, the distance between the area array light source 31 and the imaging lens 33 should be appropriately designed based on the characteristics of the area array light source 31. This ensures that the image matches the imaging lens 33 without the use of optical components, thus avoiding the reduction in light energy utilization caused by the introduction of optical components.

[0068] Figure 21 A schematic diagram of the structure of a substrate 2101 provided in one or more embodiments of the present application; in some embodiments, the laser projection imaging device may further include a substrate 2101, a driving circuit 311 and a pixel unit 312 integrated on one side of the substrate 2101; and the pixel unit 312 is located on the side of the driving circuit 311 away from the substrate 2101. Figure 20 , the embodiment of the present application can utilize microfabrication (such as mass transfer, microtubing, etc.) technology to integrate the pixel unit 312 in the above embodiment into the same base substrate 2101. The base substrate 2101 can be made of glass, silicon, sapphire and other materials. A set of electrodes (not shown) can be made on the substrate through microfabrication technology to achieve control of the driving circuit 311. The light-emitting units prepared on different epitaxial substrates can be quickly and accurately transferred to the base substrate 2101 through mass transfer or microtubing technology, and good electrical connection and mechanical fixation can be formed between them and the driving circuit 311. This method does not need to consider the lattice matching characteristics of the R / G / B epitaxial material and the base substrate 2101, which can greatly improve the stability and reliability of the VCSEL light-emitting unit and extend its working life. If the lattice constant of the epitaxial material does not match that of the base substrate 2101, defects will be introduced, which will seriously affect the output performance of the light-emitting unit.

[0069] Figure 22 A schematic diagram of a connection method for a computer controller 2201 provided in one or more embodiments of the present application; in some embodiments, in order to control the driving circuit 311 so that the light-emitting unit can emit a laser beam with parameters such as a specific color and a specific brightness, a computer controller 2201 can also be provided and connected to the driving circuit 311; Figure 21The drive circuit 311 is not shown in the figure and is only shown as being electrically connected to the base substrate 2101. However, it should be understood that the drive circuit 311 is disposed on the base substrate 2101 and that the computer controller 2201 is actually electrically connected to the drive circuit 311. The computer controller 2201 can transmit control signals to the drive circuit 311 in response to the image to be projected. The drive circuit 311 is correspondingly configured to drive the corresponding light-emitting unit in an electrically addressable manner based on the control signals, so that the area array light source 31 emits the target image corresponding to the image to be projected.

[0070] In some embodiments, there is no fixed phase relationship between the light-emitting units, and the coherence is weak, which is conducive to improving speckle. To further reduce speckle, an optical element 2301 can be provided between the area array light source 31 and the imaging lens 33. The optical element 2301 is provided in a one-to-one correspondence with the light-emitting unit. The optical element 2301 can be used to reduce imaging speckle. Figure 23 This is a schematic diagram of the structure of another laser projection imaging device provided in one or more embodiments of the present application. The optical element 2301 can be at least one of a wave plate, a compound eye, and a diffractive optical element. For example, a wave plate can be set between the array light source 31 and the imaging lens. The wave plate changes the phase of the laser beam to reduce the coherence between different laser beams, thereby reducing speckle. Specifically, a corresponding wave plate can be set according to the polarization state of the laser beam and a specific wave plate axis direction can be set. Taking linearly polarized light as an example, a quarter wave plate or a half wave plate can be set, wherein the phase delay difference in the linear polarization direction of the quarter wave plate and the half wave plate is π / 2 and π, respectively, and the corresponding phase propagation distances are λ / 4 and λ / 2, respectively. In some embodiments, the axis direction of the quarter wave plate or the half wave plate can be determined based on actual needs. For example, if the laser beam is linearly polarized light and needs to remain linearly polarized light after passing through the wave plate, the polarization direction of the linearly polarized light needs to be maintained along a certain axis of the quarter wave plate or the half wave plate, so that the polarization direction does not change. If the polarization direction of the laser beam incident on the half-wave plate does not coincide with any axis, the polarized light remains polarized, but the polarization direction is rotated. For example, if the angle between the linearly polarized light and the axis is 45°, the polarization direction is rotated 90°. If the linearly polarized light incident on the quarter-wave plate is 45°, the linearly polarized light will be converted to circularly polarized light after passing through the quarter-wave plate (conversely, circularly polarized light will be converted to linearly polarized light after passing through the quarter-wave plate). In some embodiments, the wave plate can be made of quartz crystal (SiO2), which has high transparency and high optical quality over a wide wavelength range. In some embodiments, it can also be made of materials such as calcite, magnesium fluoride, sapphire, mica, etc.

[0071] In order to enable the laser projection imaging device provided by the embodiment of the present application to be viewed by the user, the laser projection imaging device provided by the embodiment of the present application may further include a receiving screen 2401. Figure 24 A schematic diagram of the structure of a receiving screen 2401 is provided for one or more embodiments of the present application. The receiving screen 2401 can be positioned on the light-emitting side of the imaging lens 33. The receiving screen 2401 can receive the light emitted by the imaging lens 33 to present a projected image corresponding to the target image. For example, the type of receiving screen 2401 in the embodiments of the present application can be selected based on actual needs. As an example, the receiving screen 2401 can be a Fresnel projection screen. Specifically, a Fresnel projection screen can be composed of multiple film layers, such as a surface layer, a coloring layer, a diffusion layer, a Fresnel lens layer, and a reflective layer.

[0072] The laser projection imaging device in the embodiments of the present application can project light onto a Fresnel projection screen. The light enters the screen through refraction from the surface layer and passes through the coloring layer, diffusion layer, and so on before reaching the Fresnel lens layer. A reflective layer is provided on the back of the Fresnel lens layer. The light is reflected by the reflective layer and emitted from the screen, ultimately being received by the human eye. It should be noted that in some embodiments, the coloring layer, diffusion layer, and other film layers may be flexibly provided according to certain requirements. That is, the coloring layer, diffusion layer, and other film layers may not be separate film layers, but may be provided in the same layer as other film layers. Therefore, in some embodiments, the order in which light passes may differ from this example. However, it should be understood that this is merely an illustrative description and should not be construed as an improper description.

[0073] Figure 25 Schematic diagram of application scenarios of laser projection imaging devices provided in one or more embodiments of the present application, in which 2501 represents a forming device composed of all laser projection imaging devices in the above-mentioned embodiments except for the receiving screen 2401. During use, the computer controller 2201 can output a specific control signal to the driving circuit 311 based on the image to be output. The driving circuit 311 controls the specific light-emitting unit in each pixel unit 312 to emit a specific laser beam based on the control signal. The laser beam can be homogenized, diverged, shrunk, collimated, etc. through the microlens array 32. The laser beam passing through the microlens array 32 enters the imaging lens 33. The imaging lens 33 can project an image based on the received light spot (i.e., the laser beam), for example, projecting the projection light onto the receiving screen 2401, so that the user can view the corresponding image.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

[0075] For ease of explanation, the above description has been made with reference to specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations are possible. The above embodiments are selected and described to better explain the principles and practical applications, so that those skilled in the art can better utilize the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A laser projection imaging device, comprising: A VCSEL-based area array light source; the area array light source comprises a driving circuit and pixel units arranged in an array, the pixel units comprise a first light-emitting unit, a second light-emitting unit and a third light-emitting unit, the first light-emitting unit emits a red laser, the second light-emitting unit emits a green laser, and the third light-emitting unit emits a blue laser; The driving circuit is electrically connected to the first light emitting unit, the second light emitting unit and the third light emitting unit, and is configured to drive the corresponding light emitting unit based on an electrical addressing method so that the area array light source emits a target image; A microlens array, located at the light-emitting side of the array light source, and configured at least to homogenize the light spot of the corresponding light-emitting unit; The imaging lens is located on a side of the microlens array away from the area array light source along the light beam propagation direction, and is configured to receive the light beam after passing through the microlens area array and project an image.

2. The laser projection imaging device according to claim 1, wherein: The drive circuit array arrangement; The driving circuit is a first driving circuit with a single output, the first driving circuit is electrically connected to the light-emitting units in a one-to-one correspondence, and the first driving circuit is configured to drive the corresponding light-emitting units; and / or, The driving circuit is a second driving circuit with multiple outputs. The second driving circuits are arranged in a one-to-one correspondence with the pixel units. The output ends of a single second driving circuit are respectively connected to the first light-emitting unit, the second light-emitting unit and the third light-emitting unit corresponding to the same pixel unit. The second driving circuit is configured to drive the corresponding pixel unit.

3. The laser projection imaging device according to claim 1, wherein: The driving circuit is specifically configured to apply a target operating current and / or a target modulation pulse width to the corresponding light-emitting unit; The target operating current is configured to control the brightness of the light-emitting unit; The target modulation pulse width is configured to control the grayscale of the light emitting unit.

4. The laser projection imaging device according to claim 1, wherein: The pixel unit includes a 2×2 light emitting unit array; In a single pixel unit, the number of target light-emitting units is two, and the number of light-emitting units other than the target light-emitting unit is one each; The target light emitting unit is the first light emitting unit, the second light emitting unit or the third light emitting unit.

5. The laser projection imaging device according to claim 1, wherein: In the planar array light source, the light emitting units are arranged in an array along a first direction and a second direction, and the first direction intersects the second direction; Along the first direction, the colors of the laser beams emitted by two adjacent light-emitting units are different; And / or, along the second direction, the colors of the laser beams emitted by two adjacent light-emitting units are different.

6. The laser projection imaging device according to claim 1, wherein: At least one of the light-emitting units satisfies the following settings: The first light-emitting unit includes a first light-emitting chip based on a gallium arsenide substrate, the laser wavelength of the first light-emitting chip is within 630 nanometers to 650 nanometers; the wavelengths of the emitted lasers of different first light-emitting chips are arranged at equal intervals; The second light-emitting unit includes a second light-emitting chip based on a gallium nitride substrate, the laser wavelength of the second light-emitting chip is within a range of 515 nanometers to 540 nanometers; the wavelengths of the emitted lasers of different second light-emitting chips are arranged at equal intervals; and The third light-emitting unit includes a third light-emitting chip based on a gallium nitride substrate, the laser wavelength of the third light-emitting chip is within a range of 440 nanometers to 480 nanometers; and the emitted laser wavelengths of different third light-emitting chips are arranged at equal intervals.

7. The laser projection imaging device according to claim 1, wherein: The microlens array includes microlenses arranged in an array, and the microlenses are arranged in a one-to-one correspondence with the light-emitting units; The microlens is configured to homogenize the light beam emitted by the corresponding light emitting unit, and the microlens array does not change the distribution of the target image emitted by the array light source.

8. The laser projection imaging device according to claim 1, wherein: There is a preset distance between the microlens array and the imaging lens; The microlens array is also configured to shrink the beam divergence angle, expand the beam divergence angle, or maintain a collimated beam according to the optical etendue of the imaging lens; The light beam passing through the microlens array is irradiated onto the light receiving surface of the imaging lens.

9. The laser projection imaging device according to any one of claims 1 to 8, further comprising: A substrate, the driving circuit and the pixel unit are integrated on one side of the substrate; and the pixel unit is located on a side of the driving circuit away from the substrate, and / or an optical element, located between the planar array light source and the imaging lens along the light beam propagation direction, and arranged one-to-one with the light-emitting units; the optical element is configured to reduce imaging speckle; The optical element includes at least one of a wave plate, a compound eye and a diffractive optical element.

10. The laser projection imaging device according to any one of claims 1 to 8, further comprising: A computer controller connected to the driving circuit; The computer controller is configured to transmit a control signal to the drive circuit for an image to be projected; The driving circuit is correspondingly configured to drive the corresponding light-emitting unit in an electrical addressing manner based on the control signal, so that the area array light source emits the target image corresponding to the image to be projected; and / or, The receiving screen is located at the light-emitting side of the imaging lens and is configured to receive the light emitted by the imaging lens to present a projection image corresponding to the target image.

Images