Laser speckle suppression device and device and optical equipment

Abstract

The invention discloses a laser speckle suppression device, a laser speckle suppression device and display equipment. The laser speckle suppression device comprises a piezoelectric ceramic element and a transparent solid element, wherein a hole is formed in the center of the piezoelectric ceramic element, the shape of the transparent solid element is the same as that of the center hole of the piezoelectric ceramic element, the transparent solid element is seamlessly adhered to the inner side of the piezoelectric ceramic element, and the piezoelectric ceramic element comprises at least one piezoelectric ceramic body and an electrode. The ultrasonic waves are generated through the piezoelectric ceramic element, the ultrasonic waves are spread in the radial direction with the transparent solid element as a medium, when the laser irradiates the transparent solid element with the ultrasonic wave effect, Raman-Nesss diffraction is generated, the phase of the diffracted light is modulated by the ultrasonic waves in time and space, and therefore coherence of the laser is reduced; and the purpose of inhibiting speckles is achieved.

Description

Technical Field

[0001] This application relates to the technical field of projection equipment, and more specifically to a laser speckle suppression device, apparatus, and optical equipment. Background Technology

[0002] Laser display technology uses red, green, and blue (RGB) lasers as its light source, enabling it to realistically reproduce the rich and vibrant colors of the objective world and provide a more stunning visual experience. From a colorimetric perspective, laser display achieves a color gamut coverage of over 90% of the color space recognizable by the human eye, more than double that of traditional displays. This completely overcomes the limitations of the previous three generations of display technologies, achieving the most perfect color reproduction in human history and allowing people to see the most realistic and magnificent world through display terminals.

[0003] However, when laser light is diffusely reflected from the surface of a scattering body or passes through a transparent scattering body (such as frosted glass), a randomly distributed pattern of bright and dark spots can be observed in the light field at or near the scattering surface. These spots are called laser speckles. Laser speckles severely affect the viewing experience, so eliminating laser speckles on display screens has been one of the key areas of technological research in this field in recent years. To suppress laser speckles, a device for suppressing speckles through ultrasonic vibration has been proposed. This device consists of a piezoelectric transducer and a distilled water tank, and its structure is as follows: Figure 1 As shown.

[0004] but Figure 1 The laser speckle suppression device shown uses distilled water as the ultrasonic medium. However, the projection device is an electronic device that relies on circuit boards and control chips to operate. Therefore, if the distilled water leaks, it will damage the circuit boards and control chips, causing the projection device to stop working.

[0005] The background description is provided for the purpose of understanding the relevant technologies in this field and is not intended as an admission of prior art. Summary of the Invention

[0006] Therefore, the present invention aims to provide a laser speckle suppression device with higher practicality and reliability. By combining piezoelectric ceramic elements with transparent solid elements, and using a transparent solid disc as the transmission medium for ultrasonic waves, the laser speckle suppression device is achieved, thereby solving the problem of liquid leakage in the laser speckle suppression device, which causes damage to the circuit board and control chip.

[0007] In a first aspect, embodiments of the present invention provide a laser speckle suppression device, the speckle suppression device comprising: a piezoelectric ceramic element and a transparent solid element; wherein, the piezoelectric ceramic element has a central opening, and the transparent solid element has the same shape as the central opening of the piezoelectric ceramic element and is seamlessly attached to the opening of the piezoelectric ceramic element; the piezoelectric ceramic element comprises: at least one piezoelectric ceramic body and an electrode.

[0008] Optionally, the thickness of the transparent solid element is less than or equal to the thickness of the piezoelectric ceramic element.

[0009] Optionally, the transparent solid element may be made of any one of glass, plastic, crystal, and transparent ceramic.

[0010] Optionally, the product of the thickness of the transparent solid element and the vibration frequency of the piezoelectric ceramic element satisfies the Raman-Nice diffraction condition.

[0011] Optionally, the at least one piezoelectric ceramic body is a radially polarized piezoelectric ceramic ring.

[0012] Optionally, the piezoelectric ceramic element includes: an outer diameter composite layer, a piezoelectric ceramic layer, and an inner diameter composite layer; wherein the piezoelectric ceramic layer is located between the outer diameter composite layer and the inner diameter composite layer; the inner diameter composite layer is located on the side closer to the transparent solid element; and the outer diameter composite layer is located on the side farther away from the transparent solid element.

[0013] In a second aspect of the present invention, a laser speckle suppression device is provided, the laser speckle suppression device comprising an excitation source and a laser speckle suppression device as described in any of the embodiments of the first aspect; the excitation source is electrically connected to the piezoelectric ceramic element; the excitation source is used to drive the piezoelectric ceramic element to vibrate and generate ultrasonic waves.

[0014] Optionally, the excitation source includes a signal generator and a power amplifier; the power amplifier is electrically connected to the signal generator and the piezoelectric ceramic element respectively; the signal generator is used to generate a raw signal to drive the piezoelectric ceramic element; the power amplifier is used to amplify the raw signal to a preset threshold to drive the piezoelectric ceramic element to vibrate and generate ultrasonic waves; the raw signal is an alternating signal.

[0015] Optionally, the excitation source further includes a duty cycle regulator, which is disposed between the signal generator and the power amplifier, or between the power amplifier and the piezoelectric ceramic element;

[0016] The duty cycle regulator is used to adjust the on / off state of the output electrical signal of the excitation source.

[0017] In a third aspect of this invention, an optical device is provided, the optical device comprising a laser source module and a laser speckle suppression device as described in any embodiment of the second aspect; the laser emitted by the laser source module is transmitted through a transparent solid element in the laser speckle suppression device.

[0018] Other optional features and technical effects of the embodiments of the present invention are partly described below and partly apparent from reading this document. Attached Figure Description

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The elements shown are not limited to the scale shown in the drawings, and the same or similar reference numerals in the drawings denote the same or similar elements, wherein:

[0020] Figure 1 A schematic diagram of a prior art laser speckle suppression device is shown;

[0021] Figure 2A A schematic diagram of a front view of a laser speckle suppression device that can implement embodiments of the present invention is shown;

[0022] Figure 2B A schematic perspective view of a laser speckle suppression device that can implement embodiments of the present invention is shown;

[0023] Figure 3 A schematic diagram is shown of laser and ultrasonic waves acting on a transparent solid element, which can be used to implement embodiments of the present invention;

[0024] Figure 4 A schematic diagram of a sandwich piezoelectric ceramic body structure that can implement an embodiment of the present invention is shown;

[0025] Figure 5 A schematic diagram of a speckle suppression device that can implement an embodiment of the present invention is shown;

[0026] Figure 6 A schematic diagram of the driving principle of a piezoelectric ceramic element that can implement an embodiment of the present invention is shown;

[0027] Figure 7 A schematic diagram of the driving principle of another piezoelectric ceramic element that can implement an embodiment of the present invention is shown;

[0028] Figure 8 A schematic diagram of the output signal of a duty cycle regulator that can implement an embodiment of the present invention is shown;

[0029] Figure 9 A schematic diagram of a speckle suppression device that can implement an embodiment of the present invention is shown;

[0030] Figure 10 A schematic diagram of a projection device structure that can implement an embodiment of the present invention is shown;

[0031] Figure 11 A schematic diagram of an imaging device structure that can implement an embodiment of the present invention is shown;

[0032] Figure 12A A schematic diagram of a speckle pattern acquired by a camera when the speckle suppression device is not working is shown;

[0033] Figure 12B A schematic diagram of a speckle pattern captured by a camera when a speckle suppression device is in operation is shown. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0035] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0036] Figure 1 A schematic diagram of a prior art laser speckle suppression device is shown. Figure 1 The speckle suppression device shown includes a piezoelectric transducer and a distilled water tank. The distilled water tank is filled with liquid; the piezoelectric transducer is installed inside the cavity to generate ultrasonic waves. When the ultrasonic waves propagate in the liquid, they can form a set of periodically alternating compression and expansion regions. Compression and expansion cause changes in the density of the medium, resulting in periodic changes in the refractive index of the medium. When the laser beam passes through the laser speckle reduction device, its phase changes, generating a multi-order diffracted beam. The beams overlap, forming moving interference fringes, thereby reducing the contrast of the speckle and achieving the effect of speckle reduction.

[0037] In embodiments of the present invention, a laser speckle suppression device with higher practicality and reliability is provided. The laser speckle suppression device provided in this application uses a piezoelectric ceramic element and a transparent solid substrate to suppress laser speckle, thereby improving the problem in traditional laser speckle suppression devices where liquid leakage causes damage to the circuit board and control chip, leading to the projection device malfunctioning. The laser speckle suppression device includes: a piezoelectric ceramic element and a transparent solid element; wherein the piezoelectric ceramic element has a central opening, and the transparent solid element has the same shape as the central opening of the piezoelectric ceramic element and is seamlessly attached to the inner side of the piezoelectric ceramic element; the piezoelectric ceramic element includes: at least one piezoelectric ceramic body and an electrode.

[0038] The laser speckle suppression device is described below with reference to specific embodiments. See [link to specific embodiments]. Figure 2A .

[0039] Figure 2A A schematic diagram of a front view of a laser speckle suppression device that can implement embodiments of the present invention is shown. Figure 2A The laser speckle suppression device 20 shown includes a piezoelectric ceramic element 201 and a transparent solid element 202.

[0040] It should be noted that the piezoelectric ceramic element 201 in this embodiment is illustrated using a circular ring as an example. However, in actual applications, the shape of the piezoelectric ceramic element can be a cube, cylinder, cuboid, rectangular plate, etc. This application does not impose any specific limitations on the shape of the piezoelectric ceramic element. However, the piezoelectric ceramic element 201 needs to have a hole at its center. The shape of this hole can be circular, square, or irregular (e.g., quadrilateral, pentagon, etc.). This application does not impose any specific limitations on the shape of the hole at the center of the piezoelectric ceramic element.

[0041] The structure of the laser speckle suppression device is described in detail below. See also... Figure 2B , Figure 2B A schematic perspective view of a laser speckle suppression device that can implement embodiments of the present invention is shown. Figure 2B As shown, a transparent solid element 202 is attached to the inner side of the piezoelectric ceramic element 201. The piezoelectric ceramic element used in this application includes a piezoelectric ceramic body and electrodes.

[0042] Among them, the piezoelectric ceramic body can be a ferroelectric material, such as: barium titanate, lead titanate, potassium sodium niobate, lead metaniobate, lead zirconate titanate, lead barium niobate, magnesium-zirconium-lead titanate, niobium zinc-zirconium-lead titanate, niobium cobalt-zirconium-lead titanate, tungsten manganese-zirconium-lead titanate, etc.

[0043] It should be noted that the piezoelectric ceramic element is a radially vibrating piezoelectric ceramic element (radially polarized), and the ultrasonic waves it generates propagate radially.

[0044] Specifically, a piezoelectric ceramic element can be a single piezoelectric ceramic body formed from a piezoelectric ceramic body, with positive and negative electrodes respectively disposed on two opposing surfaces of the piezoelectric ceramic body. These two opposing surfaces can be the upper surface (first surface) and lower surface (second surface) of the piezoelectric ceramic body, or the inner side (the side closer to the solid transparent element) and the outer side (the side farther from the solid transparent element) of the piezoelectric ceramic body.

[0045] Optionally, the piezoelectric ceramic element may include multiple piezoelectric ceramic bodies of the same shape, with positive and negative electrodes provided between two adjacent piezoelectric ceramic bodies and on the end faces (upper surface (first surface) and lower surface (second surface) of the stack) of the multiple piezoelectric ceramic bodies forming a piezoelectric ceramic stack.

[0046] Furthermore, piezoelectric ceramic elements also include leads, which are soldered onto electrodes and generally include positive and negative leads.

[0047] In one possible implementation, a surface electrode is obtained by coating the surface of the piezoelectric ceramic body with metallic silver, and then a piezoelectric ceramic element is obtained by welding leads onto the surface electrode.

[0048] Furthermore, the piezoelectric ceramic element may also include a protective layer, which may be made of glass glaze. The protective layer is applied to the surface of the electrode to prevent the electrode from being oxidized.

[0049] The following is a detailed introduction to transparent solid-state components.

[0050] The transparent solid element has the same shape as the central hole of the piezoelectric ceramic element. The inner diameter of the transparent solid element is slightly smaller than that of the piezoelectric ceramic element, thus ensuring that the transparent solid element can be seamlessly attached to the inner side of the piezoelectric ceramic element, that is, inside the hole of the piezoelectric ceramic element.

[0051] Optionally, a transparent solid element is seamlessly bonded to the inner diameter of the piezoelectric ceramic element using epoxy resin. The epoxy resin eliminates air gaps between the piezoelectric ceramic element and the transparent solid element, thereby improving the transmission efficiency of the ultrasonic waves.

[0052] The transparent solid component can be made of any of the following materials: glass, plastic, crystal, and transparent ceramic.

[0053] Optionally, the thickness of the transparent solid element is less than or equal to the thickness of the piezoelectric ceramic element.

[0054] In this application, ultrasonic waves are generated by a piezoelectric ceramic element. These ultrasonic waves propagate radially through a transparent solid element. When a laser irradiates the transparent solid element that is affected by the ultrasonic waves, Raman-Nice diffraction is generated, thereby reducing the coherence of the laser and achieving the purpose of suppressing speckle.

[0055] Optionally, the frequency of the piezoelectric ceramic element and the thickness of the transparent solid element used in this application satisfy the Raman-Nice diffraction condition, as shown in Equation (1):

[0056]

[0057] Where L is the thickness of the transparent solid element, f is the vibration frequency of the piezoelectric ceramic element, v is the propagation speed of ultrasound in the transparent solid element, n0 is the refractive index of the transparent solid element when there is no ultrasound, and λ is the wavelength of the incident laser in a vacuum.

[0058] When the relationship between the frequency of the piezoelectric ceramic element and the thickness of the transparent solid element satisfies the condition shown in formula (1), Raman-Nice diffraction occurs when the laser light is incident on the transparent solid element in the speckle suppression device. See [reference needed]. Figure 3 , Figure 3 A schematic diagram is shown of a laser and ultrasound acting on a transparent solid element, which can be used to implement embodiments of the present invention.

[0059] like Figure 3 As shown, the ultrasonic wave is incident along the Y-axis and exits along the Z-axis.

[0060] Under the action of ultrasound, a transparent solid element can be equivalent to a phase grating, and its refractive index is shown in formula (2):

[0061]

[0062] Where m is the refractive index modulation constant, which is related to the ultrasonic pressure in the transparent solid element, and n(t,y) represents the refractive index at position y at time t.

[0063] When the laser passes through the transparent solid element, its phase is as shown in formula (3):

[0064]

[0065] As can be seen from formula (3), when the laser propagates in the speckle control device, its phase is a function of time and position, that is, the phase of each diffracted light is modulated in time and space.

[0066] In the embodiments of this application, ultrasonic waves are generated by a piezoelectric ceramic element. The ultrasonic waves propagate radially with a transparent solid element as the medium. When the relationship between the frequency of the piezoelectric ceramic element and the thickness of the transparent solid element satisfies formula (1), when the laser irradiates the transparent solid element with ultrasonic wave action, Raman-Nice diffraction is generated, and the phase of the diffracted light is modulated by the ultrasonic wave in time and space, thereby reducing the coherence of the laser and achieving the purpose of suppressing speckle.

[0067] In one possible implementation, the transparent solid element can be a scattering sheet. On the one hand, the rough surface of the scattering sheet can be used to scatter the laser and reduce the coherence of the laser. On the other hand, the interaction between the laser and the ultrasound can generate Raman-Nice diffraction, which can further reduce the coherence of the laser and improve the speckle suppression effect.

[0068] The piezoelectric ceramic body in this embodiment can be a sandwich-type piezoelectric ceramic body, see [link]. Figure 4 . Figure 4 A schematic diagram of a sandwich-type piezoelectric ceramic body structure that can implement embodiments of the present invention is shown. For example... Figure 4 As shown, the piezoelectric ceramic body includes an outer diameter composite layer 401, a piezoelectric ceramic layer 402, and an inner diameter composite layer 403. The piezoelectric ceramic layer 402 is located between the outer diameter composite layer 401 and the inner diameter composite layer 403. The inner diameter composite layer 403 is located on the inner side of the piezoelectric ceramic element, i.e., the side where the transparent solid element is attached. The outer diameter composite layer 401 is located on the outer side of the piezoelectric ceramic element, i.e., the side where the transparent solid element is not attached. The material of the inner diameter composite layer 403 can be a light metal (such as aluminum alloy, magnesium, calcium, titanium, potassium, strontium, barium, etc.) to improve forward radiation power. The material of the outer diameter composite layer 401 can be a heavy metal (such as steel, gold, silver, copper, iron, lead, cadmium, etc.) to reduce backward radiation power.

[0069] It should be noted that, in order to avoid the ultrasonic waves from affecting other components in the projection device, the embodiments of this application may provide sound-absorbing material on the outside of the piezoelectric ceramic body.

[0070] The sound-absorbing material can be made by mixing tungsten powder and epoxy resin in a certain proportion.

[0071] Furthermore, the sound-absorbing material is bonded to the piezoelectric ceramic body with epoxy resin.

[0072] The speckle suppression device is described in detail below. (See also:) Figure 5 . Figure 5 A schematic diagram of a speckle suppression device that can implement an embodiment of the present invention is shown. Figure 5 The speckle suppression device 50 shown includes a speckle suppression device 20 and an excitation source 501. The speckle suppression device 20 is the same as in the above embodiment and will not be described again here. The excitation source 501 is described in detail below; see [link to relevant documentation]. Figure 6 . Figure 6 A schematic diagram of the driving principle of a piezoelectric ceramic element that can implement an embodiment of the present invention is shown.

[0073] Furthermore, the excitation source 501 is a driving module for the piezoelectric ceramic element, electrically connected to the piezoelectric ceramic element, and used to drive the piezoelectric ceramic element to vibrate and generate ultrasonic waves. This application does not limit the circuit structure of the excitation source 201, as long as the aforementioned power can be achieved.

[0074] In one possible implementation, such as Figure 6 As shown, the excitation source 501 includes a signal generator 5011 and a power amplifier 5012. The signal generator 5011 is a circuit module that generates and outputs the original signal driving the piezoelectric ceramic element 201, and the power amplifier 5012 is a circuit module that amplifies the power of the original signal.

[0075] It should be noted that the signal generator 5011 generates and outputs the original signal to drive the piezoelectric ceramic element. Since the voltage and current of this original signal are relatively small, insufficient to drive the piezoelectric ceramic element to vibrate, it needs to be amplified. It should also be noted that this amplification refers to the amplification of the signal voltage or current. Then, the original signal is passed through the power amplifier 5012, and after power amplification, the voltage or current of the amplified signal reaches a certain preset threshold. Finally, the amplified signal is input to the piezoelectric ceramic element, which drives the piezoelectric ceramic element to vibrate and generate ultrasonic waves.

[0076] Optionally, the frequency of the original signal generated by the signal generator 5011 is consistent with the resonant frequency of the piezoelectric ceramic element, and correspondingly, the vibration frequency of the piezoelectric ceramic element is equal to its resonant frequency.

[0077] Optionally, the frequency of the original signal generated by the signal generator 5011 varies according to a preset value, and correspondingly, the vibration frequency of the piezoelectric ceramic element also varies.

[0078] If the preset frequency value is a specific number of frequency values, at least two frequency values, for example, the specific number of frequency values ​​are 30kHz, 40kHz and 50kHz, then the vibration frequency of the piezoelectric ceramic element 201 switches between 30kHz, 40kHz and 50kHz.

[0079] Furthermore, if the preset frequency value is a frequency range, such as 20kHz to 100kHz, then the vibration frequency of the piezoelectric ceramic element 201 at different times is a random frequency value between 20kHz and 100kHz.

[0080] It should be noted that the preset fixed frequency or preset frequency range of the above original signal must meet the conditions of formula (1).

[0081] The specific frequency values ​​and preset frequencies in the above embodiments are only for illustrative purposes, and the embodiments of this application do not impose specific limitations.

[0082] It should be noted that the original signal generated by the signal generator is an alternating electrical signal such as a sine wave, square wave, triangular wave, or sawtooth wave. This application does not impose specific restrictions on the original signal generated by the signal generator.

[0083] In some embodiments, the excitation source may further include a duty cycle adjuster, see [link to relevant documentation]. Figure 7 , Figure 7 A schematic diagram illustrating the driving principle of another piezoelectric ceramic element that can implement an embodiment of the present invention is shown. For example... Figure 7 As shown, the excitation source 501 includes a signal generator 5011, a power amplifier 5012, and a duty cycle regulator 5013. The signal generator 5011 and power amplifier 5012 are similar to those in the above embodiments and will not be described again here. The duty cycle regulator 5013 is a circuit module for adjusting the on / off state of the electrical signal output by the excitation source. In some embodiments, the duty cycle regulator 5013 may also be disposed between the signal generator and the power amplifier; this application embodiment does not impose specific limitations on the duty cycle regulator 5013.

[0084] In this embodiment, the piezoelectric ceramic element can be controlled to operate in a pulsed manner, i.e., intermittently, using a duty cycle regulator. For example, the output waveform of the signal after passing through the duty cycle regulator is shown below. Figure 8 , Figure 8 A schematic diagram of the output signal of a duty cycle regulator that can implement an embodiment of the present invention is shown. Figure 8 As shown, the excitation source outputs a signal during time period T1, and does not output a signal during time period T2. The duty cycle is T1 / (T1+T2). By not repeating this waveform, intermittent control of the output signal is achieved.

[0085] In some embodiments, the duty cycle of the duty cycle regulator is consistent with the duty cycle of the laser source. That is, when there is laser output, the piezoelectric ceramic element vibrates to generate ultrasonic waves, and when there is no laser output, the piezoelectric ceramic element does not vibrate and no ultrasonic waves are generated. In this way, the piezoelectric ceramic element can work intermittently, thereby reducing the heat accumulation on the piezoelectric ceramic element, improving the working performance of the piezoelectric ceramic element, and extending the life of the piezoelectric ceramic element.

[0086] The following is an introduction to speckle suppression equipment; see [link / reference]. Figure 9 , Figure 9 A schematic diagram of a speckle suppression device structure for implementing embodiments of the present invention is shown. Figure 9 The speckle suppression device shown includes a speckle suppression unit and a laser source module.

[0087] The laser source module is used to generate laser light, and the speckle suppression device is set in the optical path of the laser source.

[0088] Optionally, the incident laser is incident on the transparent solid element along the axial direction of the piezoelectric ceramic element, that is, the propagation direction of the laser is perpendicular to the propagation direction of the ultrasonic wave, and the laser is transmitted out from the transparent solid element.

[0089] The laser speckle suppression device provided in this application uses a transparent solid element as the transmission medium for ultrasonic waves, avoiding the problems in the lifespan, reliability, and practicality of projection equipment caused by distilled water leakage in the prior art. If the transparent solid element is a scattering sheet, the speckle suppression effect of the scattering sheet itself can also be utilized, improving the speckle suppression effect. Furthermore, piezoelectric ceramic elements and transparent solid elements are inexpensive and have no sealing requirements, thus reducing the cost of projection equipment.

[0090] This application also discloses a projection device, see [link to relevant documentation]. Figure 10 , Figure 10 A schematic diagram of a projection device structure that can implement an embodiment of the present invention is shown. For example... Figure 10 The projection device shown includes a laser light source module 1001, a laser speckle suppression device 50, an optical engine module 1003, and a projection lens 1004. The laser emitted by the laser light source module 1001 is projected after passing through the laser speckle suppression device 50, the optical engine module 1003, and the projection lens 1004 to form a projected image.

[0091] Specifically, the laser speckle suppression device 50 is located between the laser source module 1001 and the optical engine module 1003.

[0092] Furthermore, the laser source module 1001 may include red, green and blue lasers and a collimating lens;

[0093] The optical engine module 1003 may include compound eyes, relay systems, total internal reflection components, and DMD (Digital Micromirror Device), etc.

[0094] The projection device in this solution can be a projector or a laser TV, or it can be the PGU (image generation unit) in a HUD (Heads-Up Display), etc. This application does not impose specific limitations on the embodiments.

[0095] It should be noted that, Figure 10 The laser speckle suppression device 50 in the illustrated embodiment is any of the laser speckle suppression devices described in the above embodiments.

[0096] In some embodiments, the optical device is an imaging device, such as... Figure 11As shown, the laser emitted by the laser source module 1101 illuminates the object after passing through the speckle suppression device 50. Simultaneously, the image of the object is acquired by the image acquisition module 1103, such as a CCD or CMOS sensor. The imaging device in this scheme can be a camera or microscope, etc.

[0097] It should be noted that, Figure 11 The laser speckle suppression device 50 in the illustrated embodiment is any of the laser speckle suppression devices described in the above embodiments.

[0098] The laser speckle suppression device provided in this application uses a piezoelectric ceramic element and a transparent solid substrate to suppress laser speckle, thereby improving the problem in traditional laser speckle suppression devices where liquid leakage causes damage to the circuit board and control chip, resulting in the projection device being unable to continue working.

[0099] The following describes the effect of the embodiments of this application on speckle suppression. Figure 12A and Figure 12B . Figure 12A A schematic diagram of a speckle pattern acquired by a camera when the speckle suppression device is not working is shown; Figure 12B This diagram illustrates a speckle pattern captured by a camera during the operation of a speckle suppression device; as shown. Figure 12A The speckle suppression device shown is not working, and the speckle contrast of the speckle image is 54%. Figure 12B The speckle suppression device shown is working, and the speckle contrast of the speckle image is 37%, compared to... Figure 12A The speckle pattern shows a 17% reduction in speckle contrast, indicating that the speckle suppression device provided in this application has a good speckle suppression effect.

[0100] This document describes several embodiments of the present invention; however, for the sake of brevity, the descriptions of the embodiments are not exhaustive, and identical or similar features or parts between the embodiments may be omitted. In this document, "one embodiment," "some embodiments," "example," "specific example," or "some examples" refers to embodiments applicable to at least one, but not all, of the present invention. The above terms do not necessarily refer to the same embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of the different embodiments or examples.

[0101] The exemplary systems and methods of the present invention have been specifically shown and described with reference to the above embodiments, which are merely examples of the best mode for implementing the systems and methods. Those skilled in the art will understand that various changes can be made to the embodiments of the systems and methods described herein without departing from the spirit and scope of the invention as defined in the appended claims when implementing the systems and / or methods.

Claims

1. A laser speckle suppression device, characterized in that, include: Piezoelectric ceramic components and transparent solid components; The piezoelectric ceramic element has a central opening; The transparent solid element has the same shape as the central hole of the piezoelectric ceramic element and is seamlessly attached inside the hole of the piezoelectric ceramic element: The piezoelectric ceramic element includes at least one piezoelectric ceramic body and an electrode.

2. The laser speckle suppression device according to claim 1, characterized in that, The thickness of the transparent solid element is less than or equal to the thickness of the piezoelectric ceramic element.

3. The laser speckle suppression device according to claim 1, characterized in that, The transparent solid element is made of any one of glass, plastic, crystal, and transparent ceramic.

4. The laser speckle suppression device according to claim 1, characterized in that, The product of the thickness of the transparent solid element and the vibration frequency of the piezoelectric ceramic element satisfies the Raman-Nice diffraction condition.

5. The laser speckle suppression device according to claim 1, characterized in that, The at least one piezoelectric ceramic body is a radially polarized piezoelectric ceramic ring.

6. The laser speckle suppression device according to claim 4, characterized in that, The piezoelectric ceramic element includes: an outer diameter composite layer, a piezoelectric ceramic layer, and an inner diameter composite layer; The piezoelectric ceramic layer is located between the outer diameter composite layer and the inner diameter composite layer. The inner diameter composite layer is located on the side closest to the transparent solid element; The outer diameter composite layer is located on the side away from the transparent solid element.

7. A laser speckle suppression device, characterized in that, include: Excitation source and laser speckle suppression device as described in any one of claims 1-6; The excitation source is electrically connected to the piezoelectric ceramic element; The excitation source is used to drive the piezoelectric ceramic element to vibrate and generate ultrasonic waves.

8. The laser speckle suppression device according to claim 7, characterized in that, The excitation source includes a signal generator and a power amplifier; The power amplifier is electrically connected to the signal generator and the piezoelectric ceramic element, respectively. The signal generator is used to generate the original signal that drives the piezoelectric ceramic element; The power amplifier is used to amplify the original signal to a preset threshold to drive the piezoelectric ceramic element to vibrate and generate ultrasonic waves. The original signal is an alternating signal.

9. The laser speckle suppression device according to claim 8, characterized in that, The excitation source also includes a duty cycle regulator, which is disposed between the signal generator and the power amplifier, or between the power amplifier and the piezoelectric ceramic element; The duty cycle regulator is used to adjust the on / off state of the output electrical signal of the excitation source.

10. An optical device, characterized in that, It includes a laser source module and a laser speckle suppression device as described in claim 7; the laser emitted by the laser source module is transmitted through a transparent solid element in the laser speckle suppression device.

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