A dynamic speckle detection system embedded inside a laser projector

Abstract

This utility model discloses a dynamic speckle detection system embedded inside a laser projector, relating to the field of laser projector technology. It includes: a laser projection light source, a beam combining and homogenizing module, a speckle suppression module, an image modulation module, a speckle measurement module, and a speckle suppression drive module. The speckle suppression module includes a vibrating device, and the speckle measurement module includes an image acquisition unit and a control unit. The optical axis of the speckle measurement module points towards the projection screen. The output of its image acquisition unit is connected to the control unit, and the output of the control unit is connected to the speckle suppression drive module. The output of the speckle suppression drive module drives the vibrating device. This utility model embeds the speckle measurement system inside the laser projector, allowing arbitrary modulation of the speckle suppression module's operating state according to the actual projection pattern. This avoids the speckle suppression module operating at maximum performance for extended periods, reducing laser power consumption and heat dissipation burden, and significantly improving the lifespan of the speckle suppression module.

Description

Technical Field

[0001] This utility model relates to the field of laser projector technology, and in particular to a dynamic speckle detection system embedded inside a laser projector. Background Technology

[0002] Speckle is an interference effect produced when a laser beam interacts with surface irregularities. Specifically, the causes of speckle formation include the coherence of the light source, the surface irregularities of the screen, and the interaction between the beam and the surface. For laser projection, the laser is a coherent light source, meaning that the emitted light waves have a consistent phase relationship in space and time. The coherence of the laser beam is a key factor in the formation of speckle. When a laser beam illuminates an uneven surface, the light waves are scattered by tiny particles or irregularities on the surface, and the scattered light waves interfere with each other, producing intensity fluctuations. When observed by the human eye, this results in brightness variations that are not part of the grayscale values ​​of the image itself, significantly affecting the viewing experience.

[0003] The formation of speckle is also related to the surface irradiated by the laser. Projection screens are usually not perfectly smooth; their surfaces have minute irregularities (such as small particles, textures, tiny bumps or depressions), which cause the laser beam to scatter. When the laser beam encounters these surface irregularities, the light waves are scattered and interfere, forming a speckled pattern of uneven intensity. The roughness of the screen surface determines the intensity and distribution of the scattering. The rougher the surface, the larger the scattering angle, the stronger the interference effect, and the more pronounced the speckle.

[0004] In laser projection, the basic principle of using vibration to eliminate speckle is based on the idea of ​​breaking the speckle interference mode. The speckle generated by laser light is an interference effect caused by the coherence and phase fluctuations of the light wave. These effects create noticeable intensity fluctuations (i.e., speckle) on the projection screen. By applying vibration, a slight change can occur in the wavefront of the laser beam, disrupting the originally stable speckle mode and preventing it from exhibiting significant intensity fluctuations, thus suppressing the speckle.

[0005] The measurement and evaluation of speckle patterns typically involves multiple techniques and methods, primarily used to analyze the intensity, distribution, size, quantity, and impact on application scenarios of speckles. Most of these techniques utilize image processing. High-resolution cameras are used to capture speckle patterns, which are then analyzed using image processing software. Parameters such as speckle contrast are used to measure the speckle characteristics of the projected image.

[0006] However, the formation of speckle in laser projection is strongly related to the projector's light source and the projection screen used. For the same screen, different projectors will produce different speckles, so the working state of the speckle suppression module inside the projector should also be different. If the module is always allowed to work at maximum performance, it will not only increase the power consumption of the laser and increase the heat dissipation burden of the laser, but also reduce the lifespan of the module. Utility Model Content

[0007] This invention provides a dynamic speckle detection system embedded inside a laser projector, which can solve the problems in existing laser projectors that increase laser power consumption, increase the heat dissipation burden on the laser, and reduce the lifespan of the module.

[0008] The objective of this utility model can be achieved through the following technical solutions:

[0009] A dynamic speckle detection system embedded inside a laser projector, comprising:

[0010] Laser projection light source, beam combining and homogenizing module, speckle suppression module, image modulation module, projection lens, projection screen, speckle measurement module and speckle suppression driving module;

[0011] The speckle suppression module includes a vibration device, and the speckle measurement module includes an image acquisition unit and a control unit;

[0012] The optical axis of the speckle measurement module points to the projection screen, and its image acquisition unit output is connected to the control unit. The control unit output is connected to the speckle suppression drive module, and the speckle suppression drive module output drives the vibration device.

[0013] Preferably, the vibration device of the speckle suppression module is a piezoelectric ceramic actuator or an electromagnetic coil vibrator.

[0014] Preferably, the speckle measurement module further includes a calibration plate with positioning marks, and the calibration plate is mounted on the edge of the projection screen.

[0015] Preferably, the image acquisition unit is a CCD or CMOS camera, whose field of view covers the calibration plate and the projected image.

[0016] Preferably, the speckle suppression drive module includes a frequency modulation circuit for dynamically adjusting the operating frequency of the vibrating device.

[0017] Preferably, the control unit is configured to:

[0018] Calculate the speckle contrast acquired by the image acquisition unit;

[0019] When the speckle contrast is higher than the threshold, the speckle suppression drive module is triggered to increase the frequency of the vibrating device.

[0020] Preferably, the beam combining and homogenizing module includes a dichroic mirror array and an integrating bar.

[0021] Preferably, the speckle measurement module and the projection lens are integrated into the same housing, and their optical axes are parallel.

[0022] Preferably, the operating frequency adjustment range of the vibration device is 100Hz-10kHz.

[0023] Preferably, the speckle contrast threshold is set to 5%-15%.

[0024] The beneficial effects of this utility model are:

[0025] (1) The speckle measurement system is embedded inside the laser projector. The working state of the speckle suppression module can be arbitrarily modulated according to the actual projection pattern, avoiding the speckle suppression module from working at maximum performance for a long time, reducing the power consumption and heat dissipation burden of the laser, and greatly improving the service life of the speckle suppression module.

[0026] (2) By monitoring and adjusting the working status of the speckle suppression module in real time, speckle can be effectively suppressed in different projection screens and environments, thereby improving the quality of the projected image.

[0027] (3) Embed the speckle measurement system inside the laser projector to reduce interference from external equipment and improve the stability and reliability of the system. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings.

[0029] Figure 1 This is a schematic diagram of the structure of a dynamic speckle detection system embedded inside a laser projector according to the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Laser projection light source; 2. Beam combining and homogenizing module; 3. Speckle suppression module; 4. Image modulation module; 5. Projection lens; 6. Projection screen; 7. Speckle measurement module; 71. Calibration plate; 711. Positioning mark; 8. Speckle suppression drive module. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] In the description of this utility model, it should be understood that the terms "upper," "lower," "left," and "right," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on this utility model. Furthermore, "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "multiple" means two or more.

[0034] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0035] Please see Figure 1 As shown, this utility model is a dynamic speckle detection system embedded inside a laser projector, comprising:

[0036] 1. Laser projection light source; 2. Beam combining and homogenizing module; 3. Speckle suppression module; 4. Image modulation module; 5. Projection lens; 6. Projection screen; 7. Speckle measurement module; and 8. Speckle suppression driving module.

[0037] The speckle suppression module 3 includes a vibration device, and the speckle measurement module 7 includes an image acquisition unit and a control unit;

[0038] The optical axis of the speckle measurement module 7 points to the projection screen 6, and its image acquisition unit output is connected to the control unit. The output of the control unit is connected to the speckle suppression drive module 8, and the output of the speckle suppression drive module 8 drives the vibration device.

[0039] The vibration device of the speckle suppression module 3 is a piezoelectric ceramic actuator or an electromagnetic coil vibrator.

[0040] It should be noted that by selecting appropriate vibration devices, the vibration effect can be ensured to be stable and reliable, adapting to different projection requirements.

[0041] The speckle measurement module 7 also includes a calibration plate 71, which is provided with positioning marks 711 and is installed on the edge of the projection screen 6.

[0042] It should be noted that the calibration plate 71 and the positioning mark 711 improve the accuracy and efficiency of image acquisition, and facilitate the subsequent calculation of speckle contrast.

[0043] The image acquisition unit is a CCD or CMOS camera, whose field of view covers the calibration plate 71 and the projected image.

[0044] It should be noted that the field of view covers the calibration plate 71 and the projected image to ensure comprehensive capture of the projected image and information from the calibration plate 71, providing accurate data for speckle measurement.

[0045] The speckle suppression driving module 8 includes a frequency modulation circuit for dynamically adjusting the operating frequency of the vibrating device.

[0046] It should be noted that the frequency modulation circuit enables dynamic adjustment of the operating frequency of the vibrating device to adapt to different projection requirements and improve speckle suppression.

[0047] The control unit is configured to:

[0048] Calculate the speckle contrast acquired by the image acquisition unit;

[0049] When the speckle contrast is higher than the threshold, the speckle suppression drive module 8 is triggered to increase the frequency of the vibrating device.

[0050] It should be noted that the configuration of the control unit enables the automation and intelligence of speckle suppression, reducing manual intervention and improving suppression efficiency.

[0051] The beam combining and homogenizing module 2 includes a dichroic mirror array and an integrating bar.

[0052] It should be noted that by optimizing the beam uniformity effect, the quality and clarity of the projected image are improved.

[0053] The speckle measurement module 7 and the projection lens 5 are integrated in the same housing, and their optical axes are parallel.

[0054] It should be noted that the speckle measurement module 7 and the projection lens 5 are integrated into the housing to reduce the system size, improve integration and portability, and facilitate installation and maintenance.

[0055] The operating frequency adjustment range of the vibration device is 100Hz-10kHz.

[0056] It should be noted that by providing a wide frequency adjustment range, it can adapt to different speckle suppression needs and ensure the suppression effect.

[0057] The speckle contrast threshold is set to 5%-15%.

[0058] It should be noted that by setting a threshold, precise control of speckle suppression can be achieved, avoiding over-suppression or under-suppression, and improving the user experience.

[0059] The working principle of this invention is as follows: Initially, the laser projection light source 1 passes through the beam combining and homogenizing module 2 and the speckle suppression module 3 before entering the image modulation module 4. The image is then projected onto the projection screen 6 via the projection lens 5. At this point, the speckle suppression module 3 is not operating at a suitable state, primarily due to the relatively low vibration frequency of its vibrating device. Consequently, the speckle measurement module 7 measures a noticeable speckle pattern on the screen. This information is fed back to the speckle suppression drive module 8, which then increases the frequency of the vibrating device in the speckle suppression module 3 until the speckle contrast measured by the speckle measurement module 7 meets the display requirements. This indicates that the speckle suppression module 3 is operating at its optimal state. When switching to a new projection screen, the above steps are simply repeated.

[0060] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A dynamic speckle detection system embedded inside a laser projector, characterized in that, include: Laser projection light source (1), beam combining and homogenizing module (2), speckle suppression module (3), image modulation module (4), projection lens (5), projection screen (6), speckle measurement module (7), and speckle suppression driving module (8); The speckle suppression module (3) includes a vibration device, and the speckle measurement module (7) includes an image acquisition unit and a control unit; The optical axis of the speckle measurement module (7) points to the projection screen (6), and its image acquisition unit output is connected to the control unit. The output of the control unit is connected to the speckle suppression drive module (8), and the output of the speckle suppression drive module (8) drives the vibration device.

2. The dynamic speckle detection system embedded inside a laser projector according to claim 1, characterized in that, The vibration device of the speckle suppression module (3) is a piezoelectric ceramic actuator or an electromagnetic coil vibrator.

3. The dynamic speckle detection system embedded inside a laser projector according to claim 1, characterized in that, The speckle measurement module (7) also includes a calibration plate (71), which is provided with positioning marks (711) and is installed on the edge of the projection screen (6).

4. The dynamic speckle detection system embedded inside a laser projector according to claim 3, characterized in that, The image acquisition unit is a CCD or CMOS camera, whose field of view covers the calibration plate (71) and the projected image.

5. The dynamic speckle detection system embedded inside a laser projector according to claim 1, characterized in that, The speckle suppression drive module (8) includes a frequency modulation circuit for dynamically adjusting the operating frequency of the vibrating device.

6. The dynamic speckle detection system embedded inside a laser projector according to claim 1, characterized in that, The control unit is configured to: Calculate the speckle contrast acquired by the image acquisition unit; When the speckle contrast is higher than the threshold, the speckle suppression drive module (8) is triggered to increase the frequency of the vibrating device.

7. The dynamic speckle detection system embedded inside a laser projector according to claim 1, characterized in that, The beam combining and homogenizing module (2) includes a dichroic mirror array and an integrating bar.

8. The dynamic speckle detection system embedded inside a laser projector according to claim 1, characterized in that, The speckle measurement module (7) and the projection lens (5) are integrated in the same housing and their optical axes are parallel.

9. A dynamic speckle detection system embedded inside a laser projector according to claim 1, characterized in that, The operating frequency adjustment range of the vibration device is 100Hz-10kHz.

10. A dynamic speckle detection system embedded inside a laser projector according to claim 6, characterized in that, The speckle contrast threshold is set to 5%-15%.

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