CN107678173A - The flexible varied angle slot array diffraction optical device suppressed for laser speckle - Google Patents

Abstract

A kind of flexible varied angle slot array diffraction optical device suppressed for laser speckle, the diffraction optical device is produced on flexible material, it is formed by connecting by N group one-dimensional binaries diffractive optical structure head and the tail, the one-dimensional binary diffractive optical structure includes optical grating construction and optical microstructures, it is described it is one-dimensional refer to that diffractive optical structure is one-dimensional patterns, the binary refers to because the optical path difference that diffractive optical structure depth is formed is binaryzation.The present invention provides that a kind of all band speckle inhibition is good, motion mode is simple, be easily achieved and system versatility, robustness are good, cost the is cheap flexible varied angle slot array diffraction optical device for being used for laser speckle and suppressing, the caterpillar drive that made using flexible material, infinitely can be at the uniform velocity circulated by varied angle slot array diffraction structure, structure replace reciprocating machine motion to realize that red, green, blue all band laser speckle suppresses.

Description

Flexible variable-angle array diffractive optics for laser speckle suppression

technical field

The invention belongs to the field of laser display projection, in particular to a diffractive optical device for laser speckle suppression.

Background technique

Laser projection display system is getting more and more attention and welcome because of its rich colors, high picture quality, long life, high reliability, high efficiency, low energy consumption and other advantages. However, since laser light is highly coherent light, a picture noise called laser speckle will inevitably be generated. Speckle appears as black spots randomly distributed in the laser spot, and its essence is the random coherent superposition of signals. The existence of speckle seriously affects the quality of images and information. In the field of laser projection display, speckle will degrade the image quality of projection display, cause viewers to experience symptoms such as fatigue and dizziness, seriously affect the experience of laser projector users, and become the core factor restricting the development of laser projection display systems and instruments . Therefore, it is necessary to develop laser speckle suppression technology and devices.

The suppression of laser speckle in the prior art has adopted the following technical solutions, including: using moving diffractive optical devices; using special projection screens; using multi-angle illumination light; using special optical fibers/light pipes; using internal structures that can change dynamically of new materials. So far, there are only theoretical and preliminary experimental reports on the technical solutions based on new materials, which will not be practically applied in the short term due to the slow response speed. Although several other technical solutions have been tried to varying degrees, they all have the following disadvantages: the effect of speckle suppression is not good enough, the number and types of devices used are large, the moving parts are complex and have impact damage to the instrument, the size is large, and the structure of the instrument is complex , high energy consumption, need to be improved urgently. The closest thing to the present invention in the above-mentioned prior art is a moving diffractive optical device. For example, in "Hadamard speckle contrast reduction" (2004, Opt.Lett.29,11-13) Jahja I. Diffractive optical device based on Hadamard matrix structure; in the article "Fullspeckle suppression in laser projectors using two Barker code-type diffractive optical elements" (2013, J.Opt.Soc.Am.A 30,22-31), Lapchuk et al. adopted Two diffractive optical devices based on the Barker code structure have carried out speckle suppression experiments on full-band (including red, green, and blue) lasers; Laser Speckle Suppression Method Based on Optical Diffraction Element" (CN 106896520A) proposes to use a moving binary optical diffraction element to suppress laser speckle.

However, the above-mentioned prior art methods based on motion diffractive optics all have drawbacks. Either the degree of speckle suppression is not enough; or it is not possible to perform full-band speckle suppression; or the accuracy of the structural design is too high, and the system's fault tolerance, robustness, and versatility are poor. It is only suitable for laboratories and cannot meet practical applications. Requirements; or reciprocating mechanical movement is required, and the speed is changed during the movement, resulting in poor speckle suppression effect, etc.

Contents of the invention

In order to overcome the deficiencies of the prior art that the speckle suppression effect is not good enough, full-band speckle suppression cannot be performed, the number and types of devices used in the system are large, the moving parts are complex and have impact damage to the instrument, the size is large, the structure of the instrument is complex, and the energy consumption is high. , the present invention provides a flexible variable-angle array diffractive optical device for laser speckle suppression with good full-band speckle suppression effect, simple movement mode, easy implementation, system versatility, good robustness, and low cost. Made of flexible materials, through variable-angle array diffraction structures, a crawler-type transmission that can circulate infinitely at a constant speed can replace reciprocating mechanical motion to achieve red, green, and blue full-band laser speckle suppression.

The technical solution adopted by the present invention to solve its technical problems is:

A flexible variable-angle array diffractive optical device for laser speckle suppression. The diffractive optical device is made on a flexible material and is composed of N groups of one-dimensional binary diffractive optical structures connected end to end. The one-dimensional binary diffractive The optical structure includes a grating structure and an optical microstructure. The one-dimensional means that the diffractive optical structure is a one-dimensional pattern, and the binary means that the optical path difference formed by the depth of the diffractive optical structure is binarized.

Further, the one-dimensional binary diffractive optical structure pattern is represented by a parameter T, and the parameter T is the minimum unit width of the optical microstructure, and the width of all optical microstructures is represented by an integer multiple of T, and the one-dimensional two-dimensional The total width of the meta-diffractive optical structure pattern is represented by T ₀ ; the depth of the one-dimensional binary diffractive optical structure is h, and the inclination angle between the one-dimensional binary diffractive optical structure and the X axis is θ ₀ .

Still further, the optical microstructure is an optical microstructure based on a pseudo-random sequence, an optical microstructure based on an M sequence, or an optical microstructure based on a Barker code.

Furthermore, the N is a positive integer, representing the number of arrays included in the flexible variable-angle array diffractive optical device, N=1, 2, 3...∞, when N=1, the laser speckle suppression The flexible variable-angle array diffractive optical device is a single diffractive optical device, that is, a diffractive optical device unit, and each diffractive optical device unit includes a one-dimensional binary diffractive optical structure pattern with the same structural parameters of m periods; when N≧2, The flexible variable-angle array diffractive optical device for laser speckle suppression is a diffractive optical device comprising N arrays; the N diffractive optical device units in the array are fabricated on a single piece of flexible material at one time, and the array The one-dimensional binary diffractive optical structure patterns inside the N diffractive optical device units are the same or different, the N groups of one-dimensional binary diffractive optical structures are connected end to end, and the heads of the first group of diffractive optical structures are connected along the Y-axis direction It is connected with the tail of the Nth group of diffractive optical structures.

Preferably, the N diffractive optical device units in the array have different inclination angles from the X axis, expressed as θ _±i , where θ _±i = θ ₀ ±(N-1)/2·Δθ±i·Δθ, where Δθ represents The variation range of the inclination angle between adjacent diffractive optical device units and the X-axis.

The depth h of the binary diffractive optical structure is related to the refractive index of the flexible material, which ranges from 350nm to 650nm.

The flexible material refers to a material that is transparent to visible light bands including red, green, and blue light, soft and bendable, and includes thermoplastic or photoresist materials.

The thermoplastics include polyethylene terephthalate PET, polyvinyl chloride PVC or polycarbonate PC.

The photoresist material includes polydimethylsiloxane PDMS or photosensitive polyimide photoresist PSPI.

The technical idea of the present invention is to change the phase distribution of the laser beam by making a variable-angle array diffractive optical device on a single piece of flexible material, using the moving diffractive optical microstructure, and destroying the spatial coherence of the laser, thereby achieving the effect of suppressing speckle Effect.

Furthermore, by using the bending of flexible materials, N groups of different one-dimensional binary diffractive optical structures are superimposed on each other; the superimposed optical structures are dynamically changed by continuous crawler movement, so as to achieve the effect of full-band laser speckle suppression and Improve laser speckle suppression rate.

Furthermore, since the crawler transmission is repeated, it effectively avoids the change of the movement speed during the reciprocating mechanical movement, and reduces the system damage caused by the impact of the mechanical movement and the interference noise caused by the change of the movement speed.

Furthermore, by inventing the variable-angle array structure, the technical effect of two-dimensional displacement is realized when only one-dimensional movement is required.

The beneficial effects of the present invention are mainly manifested in:

(1) The use of flexible materials makes crawler continuous movement possible.

(2) Multiple groups of diffractive optical microstructures are fabricated on a single sheet material, with small size and high efficiency.

(3) By using the bending of flexible materials and continuous crawler movement, N groups of different one-dimensional binary diffractive optical structures are superimposed and dynamically changed to achieve full-band laser speckle suppression.

(4) By inventing the variable-angle array structure, the technical effect of two-dimensional displacement is realized when only one-dimensional movement is required.

(5) The crawler movement is used instead of the reciprocating mechanical movement, which has a more stable speckle suppression effect and less noise interference, and also makes the whole structure more stable.

(6) The entire speckle suppression system has a simple structure, stability, good versatility, high efficacy, and low energy consumption.

(7) It can be directly refitted on an existing laser projector without repurchasing.

(8) Compared with the existing speckle suppression devices on the market, the fabrication is simple, the cost is low, and it is suitable for mass production.

Description of drawings

Fig. 1 is a schematic diagram of the diffractive device unit in the flexible variable-angle array diffractive optical device of the present invention (the optical microstructure is M sequence as an example).

Fig. 2 is a schematic diagram of the array arrangement of the flexible variable-angle array diffractive optical device of the present invention.

Fig. 3 is a schematic diagram of the system for realizing laser speckle suppression by the flexible variable-angle array diffractive optical device of the present invention, wherein, 1 is a laser; 2 is a plano-convex lens; 3 is an aperture; 4 is a flexible variable-angle array diffractive optical device of the present invention and its Crawler transmission device; 5 is an imaging lens; 6 is a projection screen; 7 is a CCD camera and its computer processing system.

Fig. 4 is a schematic diagram of the flexible variable-angle array diffractive optical device of the present invention and its crawler-type transmission device and transmission mode, wherein, 1 is the position where the laser is irradiated on the flexible variable-angle array diffractive optical device of the present invention; 3 is the gear connected to the stepping motor; 4 is two springs that provide tension for the flexible variable-angle array diffractive optical device of the present invention; 5 is the track that controls the flexible variable-angle array diffractive optical device of the present invention to perform crawler movement The electrical control module; 6 indicates that the second rotating column is fixed with a spring, so that the flexible variable-angle array diffractive optical device of the present invention is always in a stretched state.

Fig. 5 is a technical principle diagram of realizing two-dimensional displacement effect by using one-dimensional direction movement in the present invention.

Figure 6 is the results of speckle suppression of red laser light by the flexible variable-angle array diffractive optical device of the present invention, Figure 6(a) is the light field distribution before speckle suppression, and Figure 6(b) is the light field after speckle suppression field distribution.

Figure 7 is the result of speckle suppression of green laser light by the flexible variable-angle array diffractive optical device of the present invention, Figure 7(a) is the light field distribution before speckle suppression, and Figure 7(b) is the light field after speckle suppression field distribution.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to Figures 1 to 7, a flexible variable-angle array diffractive optical device for laser speckle suppression is fabricated on a flexible material and is composed of N groups of one-dimensional binary diffractive optical structures connected end to end. The one-dimensional binary diffractive optical structures include but not limited to grating structures, optical microstructures based on pseudo-random sequences, optical microstructures based on M sequences, and optical microstructures based on Barker codes. The one-dimensional means that the diffractive optical structure is a one-dimensional pattern, and the binary means that the optical path difference formed due to the depth of the diffractive optical structure is binarized. The one-dimensional binary diffractive optical structure pattern is represented by parameter T (see accompanying drawing 1, the optical microstructure schematic diagram based on M sequence), and described parameter T is the minimum unit width of optical microstructure, and the width of all optical microstructures is equal to It is represented by an integer multiple of T, and the total width of the one-dimensional binary diffractive optical structure pattern is represented by T ₀ . The depth of the one-dimensional binary diffractive optical structure is h, and the inclination angle between the one-dimensional binary diffractive optical structure and the X axis is θ ₀ .

Further, the N is a positive integer, N=1, 2, 3...∞, when N=1, the flexible variable-angle array diffractive optical device for laser speckle suppression degenerates into a single diffractive optical device ( Hereinafter referred to as a diffractive optical device unit); when N≧2, it is an array diffractive optical device. Each of the diffractive optical device units includes m periods of one-dimensional binary diffractive optical structure patterns with the same structural parameters. The N diffractive optical device units in the array are fabricated on a single piece of flexible material at one time, and the one-dimensional binary diffractive optical structure patterns inside the N diffractive optical device units in the array may be the same or different. The N sets of one-dimensional binary diffractive optical structures are connected head to tail, but not limited to adhesive bonding, hot pressing, etc., and the head of the first set of diffractive optical structures is connected to the head of the Nth set of diffractive optical structures along the Y-axis direction. The tails are connected.

In the flexible variable-angle array diffractive optical device for laser speckle suppression, the N diffractive optical device units in the array have different inclination angles from the X axis, expressed as θ _±i , where θ _±i =θ ₀ ± (N-1)/2·Δθ±i·Δθ, where Δθ represents the variation range of the inclination angle between adjacent diffractive optical device units and the X-axis.

In the flexible variable-angle array diffractive optical device for laser speckle suppression, the depth h of the binary diffractive optical structure is related to the refractive index of the flexible material, and its range is from 350nm to 650nm.

Still further, the flexible material refers to a soft and bendable material that is transparent to visible light bands including red, green, and blue light. Including but not limited to polyethylene terephthalate (PET), polyvinyl chloride (PVC), polycarbonate (PC) and other thermoplastics; also including but not limited to polydimethylsiloxane (PDMS), Photoresist materials such as photosensitive polyimide photoresist (PSPI).

The specific method for suppressing laser speckle based on a flexible variable-angle array diffractive optical device of the present invention is as follows:

Step 1: Install a flexible variable-angle array diffractive optical device of the present invention on a crawler conveyor based on gear transmission as a mechanical module of the laser speckle suppression system.

Step 2: The crawler conveyor described in step 1 is controlled by an electrical control module. The electrical control module is driven by a stepping motor to control the flexible variable-angle array diffractive optical device to perform continuous crawler movement.

Step 3: Place the mechanical module driven by the electrical control module in the laser speckle suppression system, and combine with the optical module to realize the laser speckle suppression function. The optical module includes a laser, a modulation lens assembly, a flexible variable-angle array diffractive optical device of the present invention, an imaging lens, a projection screen, a CCD camera and a computer processing system thereof. The modulation lens assembly includes a plano-convex lens and a diaphragm. The laser, the modulation lens assembly, the flexible variable-angle array diffractive optical device of the present invention and the imaging lens are located on the same optical axis, and the laser beam emitted by the laser is expanded, shaped and calibrated through the modulation lens assembly, and is incident on the The invention relates to a flexible variable-angle array diffractive optical device. The flexible variable-angle array diffractive optical device of the present invention is mounted on a crawler-type conveying device driven by a stepping motor for crawler-type movement. The projection screen records laser projection images and allows direct visual observation. The CCD camera records the laser projection image on the projection screen and inputs it into a computer for subsequent data processing.

The working principle of laser speckle suppression based on a flexible variable-angle array diffractive optical device of the present invention is as follows:

1) Calculation formula of speckle contrast SC:

where σ is the standard deviation of the light intensity distribution, is the average light intensity distribution. The starting point of most speckle reduction methods is to average the light intensity distribution.

2) The present invention is a flexible variable-angle array diffractive optical device for laser speckle suppression. The flexible variable-angle array diffractive optical device is composed of N groups of one-dimensional binary diffractive optical structures connected end to end. The one-dimensional binary diffractive optical structures include but not limited to grating structures, optical microstructures based on pseudo-random sequences, optical microstructures based on M sequences, and optical microstructures based on Barker codes. Taking the optical microstructure based on the M sequence as an example, it makes the laser beam diffract, and the continuous crawler-type transmission makes N groups of one-dimensional binary diffractive optical structures superimpose and change dynamically, so that the superposition of the laser diffraction light field achieves Coherence, to achieve the effect of suppressing laser speckle. The N groups of one-dimensional binary diffractive optical structures in the present invention are superimposed and dynamically changed, which is simple and effective to achieve the same as the existing technology (Full speckle suppression in laserprojectors using two Barker code-type diffractive optical elements, 2013, J.Opt.Soc. Am.A30,22-31) similar double-sided one-dimensional M-sequence encoding effect, so full-band laser speckle suppression can be achieved.

There are two basic factors that affect the effect of laser speckle suppression: the direction of motion and the speed of motion during motion. Use the linear displacement in the X-axis direction and the Y-axis direction to determine the influence of the motion direction and speed on the speckle suppression effect. The theoretical calculation formula is as follows:

Among them, D is the projection width of the resolution unit of the human eye on the screen, x ₁ , x ₂ , y ₁ , y ₂ are the coordinates where the laser beam is projected onto the screen through two binary diffractive optical structures moving along different axes , H(x ₁ ,x ₂ ,y ₁ ,y ₂ ) and H(x ₁ ,x ₁ ,y ₁ ,y ₁ ) are the autocorrelations of the laser beam at the screen plane modulated by the M-sequence binary optical diffraction elements function:

Among them, Δt is the exposure time of the human eye; V ₁ is the moving speed of the binary optical diffraction element image on the screen along the Y-axis direction, V ₂ is the moving speed along the X-axis direction; T ₀ is a binary optical diffraction element The minimum unit length in a period; M is a non-zero integer; T(x,y,V,t) is the transmission coefficient function of the binary optical diffraction element.

Example 1:

A flexible variable-angle array diffractive optical device for laser speckle suppression is fabricated on PDMS flexible material and consists of three groups of one-dimensional binary diffractive optical structures connected end to end. The one-dimensional binary diffractive optical structure is an optical microstructure based on M sequence (see accompanying drawing 1 and accompanying drawing 2), and its one-dimensional binary diffractive optical structure pattern is represented by parameter T, and described parameter T is optical microstructure The minimum unit width of , the widths of all optical microstructures are represented by integer multiples of T, and the total width of the one-dimensional binary diffractive optical structure pattern is represented by T ₀ . The depth of the one-dimensional binary diffractive optical structure is h, and the inclination angle between the one-dimensional binary diffractive optical structure and the X axis is θ ₀ .

The T parameter is 4 microns, the depth h of the one-dimensional binary diffractive optical structure is 400 nanometers, and the M sequence code is a 31-bit code, that is, 1111100110100100001010111011000. According to formula (1), formula (2) and formula (3), choose θ ₀ to be 45° and Δθ to be 0.3°. According to the calculation formula of θ _±i = θ ₀ ±(N-1)/2·Δθ±i·Δθ, the inclination angles between the three groups of one-dimensional binary diffractive optical structures and the X-axis are 44.4°, 45°, and 45.6° respectively , using an adhesive bonding method to connect the head of the first group of diffractive optical structures to the tail of the third group of diffractive optical structures along the Y-axis direction.

Referring to FIG. 4 , a flexible variable-angle array diffractive optical device of the present invention is installed on a gear-based crawler conveyor as a mechanical module of a laser speckle suppression system. The crawler conveyor is controlled by an electrical control module. The electrical control module is driven by a stepping motor to control the flexible variable-angle array diffractive optical device to perform continuous crawler movement.

Referring to Figure 3, the mechanical module driven by the electrical control module is placed in the laser speckle suppression system, combined with the optical module, to realize the laser speckle suppression function. The optical module includes a laser, a modulation lens assembly, a flexible variable-angle array diffractive optical device of the present invention, an imaging lens, a projection screen, a CCD camera and a computer processing system thereof. The modulation lens assembly includes a plano-convex lens and a diaphragm. The laser, the modulation lens assembly, the flexible variable-angle array diffractive optical device of the present invention and the imaging lens are located on the same optical axis, and the laser beam emitted by the laser is expanded, shaped and calibrated through the modulation lens assembly, and is incident on the The invention relates to a flexible variable-angle array diffractive optical device. The flexible variable-angle array diffractive optical device of the present invention is mounted on a crawler-type conveying device driven by a stepping motor for crawler-type movement. The projection screen records laser projection images and allows direct visual observation. The CCD camera records the laser projection imaging on the projection screen and inputs it into a computer for subsequent data processing.

Due to the crawler movement, when the laser light hits one of the diffractive optical device areas, the beam passes through this area and simultaneously irradiates another area of the flexible variable-angle array diffractive optical device with a different inclination angle of the micro-optical structure, thereby forming Double-sided one-dimensional diffractive optical superposition structure. Since the two device regions move at a constant speed in opposite directions before and after the laser irradiation part, and the inclination angles of the micro-optical structures in different device regions are different, so as to achieve the displacement equivalent to the Y-axis direction. As for the moving speed of the crawler-type moving device installed with the flexible variable-angle array diffractive optical device of the present invention, it is controlled by the electrical control module.

A red laser is used as the light source, and the emitted laser beam is collimated and expanded through the plano-convex lens 2, and then the size of the aperture is changed through the diaphragm, and the laser beam is incident on the flexible variable-angle array diffractive optical device of the present invention. The flexible variable-angle array diffractive optical device is fixed on the crawler-type transmission device. When the laser beam irradiates its surface, the electrical control module is activated to control the flexible variable-angle array diffractive optical device to perform constant-speed crawler-type transmission movement. The moving flexible variable-angle array diffractive optical device changes the phase of the diffraction order within the exposure time of the human eye or the CCD camera, thereby destroying the spatial coherence of the laser beam and achieving the effect of speckle suppression.

Referring to FIG. 6 , it is a diagram showing the results of speckle suppression performed by the flexible variable-angle array diffractive optical device of the present invention for red laser light in Example 1.

Example 2:

The depth h of the one-dimensional binary diffractive optical structure is 350 nanometers, and other implementation parameters and processes are the same as those in Embodiment 1.

Referring to FIG. 7 , it is a result diagram of speckle suppression performed by the flexible variable-angle array diffractive optical device of the present invention in Embodiment 2 for green laser light.

Example 3:

The depth h of the one-dimensional binary diffractive optical structure is 650 nanometers, polyethylene terephthalate (PET) is selected as the flexible material, and other implementation parameters and processes are the same as those in Embodiment 1.

Example 4:

A flexible variable-angle array diffractive optical device for laser speckle suppression is fabricated on a polyvinyl chloride (PVC) flexible material and consists of four groups of one-dimensional binary diffractive optical structures connected end to end. The one-dimensional binary diffractive optical structure is an optical microstructure based on the M sequence (see accompanying drawing 1), and its one-dimensional binary diffractive optical structure pattern is represented by a parameter T, and the parameter T is the minimum unit width of the optical microstructure , the widths of all optical microstructures are represented by integer multiples of T, and the total width of the one-dimensional binary diffractive optical structure pattern is represented by T ₀ . The depth of the one-dimensional binary diffractive optical structure is h, and the inclination angle between the one-dimensional binary diffractive optical structure and the X axis is θ ₀ .

The T parameter is 4 microns, the depth h of the one-dimensional binary diffractive optical structure is 450 nanometers, and the M sequence code is a 31-bit code, that is, 1111100110100100001010111011000, and the inclination angles between the four groups of one-dimensional binary diffractive optical structures and the X axis are 43.5 °, 44.5°, 45.5°, 45.5°, the head of the first group of diffractive optical structures is connected to the tail of the fourth group of diffractive optical structures along the Y-axis direction by adhesive bonding.

Referring to FIG. 4 , a flexible variable-angle array diffractive optical device of the present invention is installed on a gear-based crawler conveyor as a mechanical module of a laser speckle suppression system. The crawler conveyor is controlled by an electrical control module. The electrical control module is driven by a stepping motor to control the flexible variable-angle array diffractive optical device to perform continuous crawler movement.

Referring to Figure 3, the mechanical module driven by the electrical control module is placed in the laser speckle suppression system, combined with the optical module, to realize the laser speckle suppression function. The optical module includes a laser, a modulation lens assembly, a flexible variable-angle array diffractive optical device of the present invention, an imaging lens, a projection screen, a CCD camera and a computer processing system thereof. The modulation lens assembly includes a plano-convex lens and a diaphragm. The laser, the modulation lens assembly, the flexible variable-angle array diffractive optical device of the present invention and the imaging lens are located on the same optical axis, and the laser beam emitted by the laser is expanded, shaped and calibrated through the modulation lens assembly, and is incident on the The invention relates to a flexible variable-angle array diffractive optical device. The flexible variable-angle array diffractive optical device of the present invention is mounted on a crawler-type conveying device driven by a stepping motor for crawler-type movement. The projection screen records laser projection images and allows direct visual observation. The CCD camera records the laser projection imaging on the projection screen and inputs it into a computer for subsequent data processing.

Due to the crawler movement, when the laser light hits one of the diffractive optical device areas, the beam passes through this area and simultaneously irradiates another area of the flexible variable-angle array diffractive optical device with a different inclination angle of the micro-optical structure, thereby forming Double-sided one-dimensional diffractive optical superposition structure. Since the two device regions move at a constant speed in opposite directions before and after the laser irradiation part, and the inclination angles of the micro-optical structures in different device regions are different, so as to achieve the displacement equivalent to the Y-axis direction. As for the moving speed of the crawler-type moving device installed with the flexible variable-angle array diffractive optical device of the present invention, it is controlled by the electrical control module.

A red laser is used as the light source, and the emitted laser beam is collimated and expanded through the plano-convex lens 2, and then the size of the aperture is changed through the diaphragm, and the laser beam is incident on the flexible variable-angle array diffractive optical device of the present invention. The flexible variable-angle array diffractive optical device is fixed on the crawler-type transmission device. When the laser beam irradiates its surface, the electrical control module is activated to control the flexible variable-angle array diffractive optical device to perform constant-speed crawler-type transmission movement. The moving flexible variable-angle array diffractive optical device changes the phase of the diffraction order within the exposure time of the human eye or the CCD camera, thereby destroying the spatial coherence of the laser beam and achieving the effect of speckle suppression.

Example 5:

The depth h of the one-dimensional binary diffractive optical structure is 500 nanometers, polycarbonate (PC) is selected as the flexible material, and other implementation parameters and processes are the same as those in Embodiment 4.

Embodiment 6:

The depth h of the one-dimensional binary diffractive optical structure is 550 nanometers, and the flexible material is photosensitive polyimide photoresist (PSPI). Other implementation parameters and processes are the same as those in Embodiment 4.

Claims (9)

1. A kind of 1. flexible varied angle slot array diffraction optical device suppressed for laser speckle, it is characterised in that：The diffraction light Element manufacturing is learned on flexible material, is formed by connecting by N group one-dimensional binaries diffractive optical structure head and the tail, the one-dimensional binary diffraction Optical texture includes optical grating construction and optical microstructures, it is described it is one-dimensional refer to that diffractive optical structure is one-dimensional patterns, the binary Refer to because the optical path difference that diffractive optical structure depth is formed is binaryzation.
2. 2. the flexible varied angle slot array diffraction optical device suppressed as claimed in claim 1 for laser speckle, its feature exist In：The one-dimensional binary diffractive optical structure pattern is represented that the parameter T is that the minimum unit of optical microstructures is wide by parameter T Spend, the width of all optical microstructures is represented with T integral multiple, the beam overall of the one-dimensional binary diffractive optical structure pattern Degree T₀Represent；The depth of the one-dimensional binary diffractive optical structure is h, the one-dimensional binary diffractive optical structure and X-axis institute Folder inclination angle is θ₀。
3. 3. the flexible varied angle slot array diffraction optical device suppressed as claimed in claim 2 for laser speckle, its feature exist In：The optical microstructures are the optical microstructures based on pseudo-random sequence, the optical microstructures based on M sequence or are based on The optical microstructures of Barker code.
4. 4. the flexible varied angle slot array diffraction optical device suppressed as claimed in claim 2 or claim 3 for laser speckle, its feature It is：The N is positive integer, represents the array number included in flexible varied angle slot array diffraction optical device, N=1,2, 3 ... ∞, as N=1, the flexible varied angle slot array diffraction optical device suppressed for laser speckle is single diffraction optics Device, i.e. diffraction optical device unit, each diffraction optical device unit include the structural parameters identical one in m cycle Tie up Binary Diffractive Optics structure plan；As N≤2, the flexible varied angle slot array diffraction optics suppressed for laser speckle Device is the diffraction optical device for including N number of array；N number of diffraction optical device unit in the array is disposably produced on list On piece flexible material, the one-dimensional binary diffractive optical structure pattern inside N number of diffraction optical device unit in its array is identical Or differ, N groups one-dimensional binary diffractive optical structure head and the tail connect, along Y direction by the 1st group of diffractive optical structure Head is connected with the tail of N group diffractive optical structures.
5. 5. the flexible varied angle slot array diffraction optical device suppressed as claimed in claim 4 for laser speckle, its feature exist In：N number of diffraction optical device unit in array is different from inclination angle folded by X-axis, is expressed as θ_±i, wherein θ_±i=θ₀±(N-1)/ 2 Δ θ ± i Δ θ, Δ θ represent neighboring diffraction optical device unit and the amplitude of variation at inclination angle folded by X-axis.
6. 6. the flexible varied angle slot array diffraction optical device for being used for laser speckle and suppressing as described in one of claims 1 to 3, its It is characterised by：The depth h of Binary Diffractive Optics structure is relevant with the refractive index of flexible material, and its scope is in 350nm to 650nm.
7. 7. the flexible varied angle slot array diffraction optical device for being used for laser speckle and suppressing as described in one of claims 1 to 3, its It is characterised by：The flexible material refers to transparent to the visible light wave range including red, green, blue, soft bent Material, the flexible material include thermoplastic or Other substrate materials.
8. 8. the flexible varied angle slot array diffraction optical device suppressed as claimed in claim 7 for laser speckle, its feature exist In：The thermoplastic includes polyethylene terephtalate, polyvinylchloride or polycarbonate.
9. 9. the flexible varied angle slot array diffraction optical device suppressed as claimed in claim 7 for laser speckle, its feature exist In：The Other substrate materials include polydimethylsiloxane or light-sensitive polyimide photoresist PSPI.