Projection lens, focusing method, focusing device, storage medium, computer program product and projection equipment

Abstract

The invention discloses a projection lens, a focusing method, a focusing device, a storage medium, a computer program product and projection equipment, and relates to the technical field of projection display, the projection lens comprises a first lens group, a diaphragm and a second lens group which are sequentially arranged along the horizontal direction; the light source is arranged on one side of the second lens group, and light emitted by the light source sequentially passes through the second lens group, the diaphragm and the first lens group to form a light path; the electro-optical modulation crystal is arranged in the light path. The invention aims to improve the focusing response speed and the focusing precision and reduce the cost.

Description

Technical Field

[0001] The present invention relates to the field of projection display technology, and in particular to a projection lens, a focusing method, a focusing device, a storage medium, a computer program product and a projection device. Background Art

[0002] DLP (Digital Light Procession) projection systems are widely used in home entertainment, education, and business due to their high resolution, high contrast, and compact design. However, existing DLP projection systems generally use mechanical focusing, which has problems such as slow response speed, limited focusing accuracy, and mechanical wear. Specifically, mechanical focusing is achieved by driving the lens forward and backward with a motor. The response time is long and the focusing is not completely continuous. The minimum driving distance limits the focusing accuracy. Long-term use will cause wear of mechanical parts and increase maintenance costs. At the same time, in order to ensure a close fit between the lens and the lens barrel, precision machining is required on the flange structure, which increases manufacturing costs. Summary of the invention

[0003] The main purpose of the present invention is to provide a projection lens, a focusing method, a focusing device, a storage medium, a computer program product and a projection device, aiming to improve the focusing response speed and focusing accuracy, and reduce the cost.

[0004] To achieve the above object, the present invention provides a projection lens, which includes a first lens group, an aperture, and a second lens group arranged in sequence along a horizontal direction; and

[0005] A light source is disposed on one side of the second lens group, and light emitted by the light source passes through the second lens group, the aperture and the first lens group in sequence to form a light path;

[0006] An electro-optical modulation crystal is arranged in the optical path.

[0007] In one embodiment, the electro-optic modulation crystal is disposed between the light source and the second lens group.

[0008] In one embodiment, the electro-optic modulation crystal is a galvanometer.

[0009] In one embodiment, the electro-optic modulation crystal is disposed in the first lens group or the second lens group.

[0010] In one embodiment, when the electro-optical modulation crystal is disposed in the first lens group, the first lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power;

[0011] The electro-optical modulation crystal is any one or more of the first lens, the second lens, and the third lens.

[0012] In one embodiment, when the electro-optical modulation crystal is disposed in the first lens group, the first lens group includes a fourth lens with negative optical power and a fifth lens with positive optical power;

[0013] The electro-optical modulation crystal is any one or more of the fourth lens and the fifth lens.

[0014] In one embodiment, when the electro-optical modulation crystal is disposed in the second lens group, the second lens group includes a sixth lens with negative optical power, a seventh lens with negative optical power, and an eighth lens with positive optical power;

[0015] The electro-optical modulation crystal is any one or more of the sixth lens, the seventh lens, and the eighth lens.

[0016] In one embodiment, the electro-optic modulation crystal includes any one of potassium titanate crystal, lithium niobate crystal, and gallium arsenide crystal.

[0017] The present invention further provides a focusing method, which is applied to a projection device, wherein the projection device comprises a projection lens as described in any one of the above items, and a screen, wherein the projection lens comprises an electro-optical modulation crystal, which is used to modulate the light emitted by the light source and then project it onto the screen, and the focusing method comprises:

[0018] Get the clarity of the image projected onto the screen;

[0019] Calculating the refractive index change amount that needs to be adjusted for the electro-optical modulation crystal according to the image clarity and the preset clarity;

[0020] The voltage change is determined according to the refractive index change, and a voltage of a corresponding magnitude is applied to the conductive element of the electro-optical modulation crystal according to the voltage change, so as to adjust the image clarity to a preset clarity.

[0021] In one embodiment, determining the voltage change amount according to the refractive index change amount specifically includes:

[0022] Obtaining the thickness of the electro-optical modulation crystal;

[0023] The product of the refractive index variation and the thickness of the electro-optic modulation crystal is calculated to determine the voltage variation according to the quotient of the product and the electro-optic coefficient.

[0024] In one embodiment, after applying a voltage of a corresponding magnitude to the conductive element of the electro-optical modulation crystal according to the voltage variation, the focusing method further comprises:

[0025] The step of calculating the definition of the image on the screen is re-executed until the definition of the image is adjusted to a preset definition.

[0026] In one embodiment, the projection device further includes a distance sensor disposed at the location of the projection lens, and the calculation of the clarity of the image on the screen specifically includes:

[0027] Obtain the distance between the projection lens and the screen to calculate the clarity of the image on the screen according to the distance;

[0028] and / or, photographing the image on the screen to obtain a real-time image;

[0029] The real-time image is processed using a preset image processing algorithm to obtain the clarity of the image on the screen.

[0030] The present invention also proposes a focusing device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of any of the above-mentioned focusing methods.

[0031] The present invention further proposes a storage medium, which is a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, the steps of the focusing method described in any one of the above items are implemented.

[0032] The present invention also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the steps of any one of the focusing methods described above are implemented.

[0033] The present invention further provides a projection device, comprising the projection lens as described in any one of the above items, and the focusing device as described in the above items.

[0034] In one embodiment,

[0035] In one embodiment, the projection device comprises:

[0036] A power supply electrically connected to the focusing device;

[0037] A conductive member, the conductive member being arranged on the electro-optical modulation crystal;

[0038] Electrodes, the electrodes are electrically connected to the conductive member and the power supply respectively;

[0039] The focusing device is used to control the power supply to apply a voltage corresponding to the voltage change amount to the electro-optical modulation crystal through the electrode.

[0040] The present invention proposes a projection lens, which includes a first lens group, an aperture, and a second lens group arranged in sequence along a horizontal direction; and a light source arranged on one side of the second lens group, the light emitted by the light source passes through the second lens group, the aperture, and the first lens group in sequence to form an optical path; and an electro-optical modulation crystal, which is arranged in the optical path.

[0041] In practical applications, the electro-optical modulator crystal can be set at any position in the optical path, as any lens or element in the optical path. For example, when focusing is required, the image projected onto the screen can be captured by the image sensor of the projection device, the image clarity can be analyzed, and the refractive index change that needs to be adjusted by the electro-optical modulator crystal can be calculated by a preset algorithm to determine the required voltage change. The focusing device of the projection device applies a voltage of corresponding magnitude to the conductive part of the electro-optical modulator crystal according to the voltage change. In this way, the image sensor continuously monitors the clarity of the image after focusing, and feeds back to the focusing device to fine-tune the voltage of the electro-optical modulator crystal until a better focusing effect is achieved. The present invention improves the focusing response speed by replacing the traditional mechanical focusing method with an electro-optical modulator crystal; and utilizes the electro-optical effect of the electro-optical modulator crystal to achieve stepless focusing, improve the limitation of the minimum driving distance, and improve the focusing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0043] Figure 1 is a schematic diagram of an embodiment of a projection lens of the present invention;

[0044] Figure 2 is a schematic diagram of another embodiment of the projection lens of the present invention;

[0045] Figure 3 is a schematic diagram of another embodiment of the projection lens of the present invention;

[0046] Figure 4 is a schematic diagram of another embodiment of the projection lens of the present invention;

[0047] Figure 5 It is a flow chart of an embodiment of a focusing method of the present invention;

[0048] Figure 6 FIG. 4 is a flow chart of another embodiment of the focusing method of the present invention.

[0049] Description of Figure Numbers:

[0050] 100, first lens group; 200, second lens group; 300, aperture; 400, electro-optic modulation crystal; 500, equivalent prism; 600, protective glass; 700, DMD chip; 10, first lens; 20, second lens; 30, third lens; 40, fourth lens; 50, fifth lens; 60, sixth lens; 70, seventh lens; 80, eighth lens.

[0051] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] It should be noted that, in this article, step codes such as S100, S200, etc. are used for the purpose of expressing the corresponding content more clearly and concisely, and do not constitute a substantial limitation on the sequence. When implementing the step, those skilled in the art may execute S200 first and then S100, etc., but these should all be within the scope of protection of this application.

[0054] DLP (Digital Light Procession) projection systems are widely used in home entertainment, education, and business due to their high resolution, high contrast, and compact design. However, existing DLP projection systems generally use mechanical focusing methods, which have problems such as slow response speed, limited focusing accuracy, and mechanical wear. Specifically, the current focusing method is mostly achieved by adjusting the distance between the projection lens and the lighting subject (light source), that is, the lens moves back and forth. The forward and backward movement of the lens is generally driven by a motor, but it takes a certain amount of time for the lens to move from one position to another, and the motor has a minimum driving distance, so the focusing is not completely continuous. In addition, the minimum driving distance limits the focusing accuracy; long-term use will cause wear of mechanical parts and increase maintenance costs; at the same time, in order to ensure a close fit between the lens and the lens barrel, precision processing is required on the flange structure, which increases the processing and manufacturing costs.

[0055] For this purpose, refer to Figure 1 The present invention provides a projection lens, which includes a first lens group 100, an aperture 300, and a second lens group 200 arranged in sequence along a horizontal direction; and

[0056] A light source is disposed at one side of the second lens group 200, and the light emitted by the light source passes through the second lens group 200, the aperture 300 and the first lens group 100 in sequence to form a light path;

[0057] The electro-optic modulation crystal 400 is disposed in the optical path.

[0058] In this embodiment, the first lens group 100 and the second lens group 200 can be implemented by a single lens, a double cemented lens, a combination of multiple lenses, etc. The first lens group 100 is mainly responsible for further focusing the light passing through the aperture 300 and projecting it onto the screen. It is usually composed of multiple lenses to correct aberrations and improve image quality. The second lens group 200 is mainly responsible for preliminarily focusing and correcting the light emitted by the light source to ensure that the light can pass through the aperture 300 evenly and be projected onto the screen after being focused by the first lens group 100. The aperture 300 can be implemented by a fixed aperture 300, a variable aperture 300, an automatic aperture 300, etc. Among them, the aperture size of the fixed aperture 300 is fixed, and the aperture size of the variable aperture 300 can be adjusted mechanically or electronically to adapt to different lighting conditions and image requirements. The aperture size of the automatic aperture 300 can be automatically adjusted according to the intensity of the ambient light. The light source can be implemented by an LED light source, a laser light source, etc.

[0059] Optionally, the electro-optical modulation crystal 400 includes any one of a potassium titanium oxide (KTP) crystal, a lithium niobate (LiNbO3) crystal, and a gallium arsenide (GaAs) crystal. Among them, potassium titanium oxide has good nonlinear optical properties and a high electro-optic coefficient, and is suitable for frequency conversion and electro-optic modulation. Lithium niobate has excellent electro-optic effect and nonlinear optical properties, high transparency and good mechanical strength. Gallium arsenide has a high electro-optic coefficient and good semiconductor properties, and is suitable for high-speed electro-optic modulation. The appropriate crystal material can be selected according to actual needs. It should be noted that when there are at least two electro-optical modulation crystals 400 in the optical path, crystals of the same or different materials can be selected to achieve it.

[0060] Specifically, when the electro-optical modulation crystal 400 is arranged in the optical path, the projection device where the projection lens is located may also include an image sensor, a camera and other image acquisition devices, and a screen. Take the projection device including an image sensor as an example for explanation. The image sensor captures the image projected on the screen after the light emitted by the light source passes through the second lens group 200, the aperture 300 and the first lens group 100 in sequence, and automatically analyzes the clarity of the image in combination with the image processing algorithm, such as image preprocessing, feature extraction, etc. The clarity result of the image is output to the projection device so that it can calculate the refractive index change amount that the electro-optical modulation crystal 400 needs to adjust through software. For example, the user can directly input the preset clarity threshold through the user interface of the projection device in advance, or send the preset clarity threshold to the main controller through the network interface of the projection device through an external terminal, so that the main controller stores the received preset clarity threshold in the internal memory, and the preset clarity threshold is a target clarity threshold, which represents the clarity required by the user. After comparing the clarity of the current image with the target clarity threshold, the clarity difference is obtained, and the refractive index change amount that needs to be adjusted is calculated. The relationship between the clarity difference and the refractive index change amount can be described by a pre-calibrated relationship curve or model.

[0061] It is understandable that, using the electro-optic effect, when the voltage applied to a material (such as the electro-optic modulation crystal 400) changes, the refractive index of the material changes accordingly. The mathematical description of the linear electro-optic effect is as follows:

[0062] △n=γE;

[0063] Where △n is the change in refractive index, γ is the electro-optic coefficient, and E is the applied electric field strength.

[0064] In the electro-optic modulation crystal 400, the relationship between the applied voltage V and the generated electric field E is:

[0065] E = V / d;

[0066] Wherein, d is the thickness of the electro-optic modulation crystal 400;

[0067] From the above formula, the relationship between the refractive index change △n and the voltage △V to be applied is as follows:

[0068] △V=d*△n / γ;

[0069] Therefore, in this embodiment, when the refractive index change that needs to be adjusted is a known quantity, the voltage that needs to be applied can be determined through the relationship between the refractive index change △n and the voltage △V that needs to be applied, and the size of the external voltage of the electro-optical modulator crystal 400 is changed according to the voltage that needs to be applied, so that the optical path of the light passing through the electro-optical modulator crystal 400 is changed, and finally the focusing of the picture is achieved.

[0070] Optionally, the projection device includes a power supply, a conductive member, an electrode and a thyristor voltage regulator, the power supply is electrically connected to the focusing device (main controller); the conductive member is arranged on the electro-optic modulation crystal 400, and the electrodes are electrically connected to the conductive member and the power supply respectively; the focusing device is used to control the power supply to apply a voltage corresponding to the voltage change amount to the electro-optic modulation crystal 400 through the electrode. In this embodiment, the conductive member can be a conductive transparent film, such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), carbon nanotubes (CNT), graphene, etc., and the conductive transparent film is prepared on the surface of the electro-optic modulation crystal 400 by deposition or coating technology. The electrode can be implemented by a metal electrode (such as gold, silver, copper) or other conductive materials. The power supply can be implemented by a DC voltage or an AC power supply. Among them, the thyristor regulator can be integrated with the main controller to reduce the wiring area, and the thyristor regulator is used to receive the control signal output by the main controller and control the voltage applied to the electro-optic modulation crystal 400. Before using the projection device, it is necessary to connect the electrodes to the conductive transparent film and connect the power supply so that the main controller can output the corresponding control signal to the thyristor voltage regulator after determining the voltage change, and control the thyristor voltage regulator to apply a voltage of corresponding magnitude to the conductive part of the electro-optical modulation crystal 400 according to the voltage change, so as to adjust the current image clarity, that is, control the focusing amplitude through the thyristor voltage regulator to achieve fast and accurate focusing operation.

[0071] In actual application, the projection device can manually set the target clarity threshold according to the user, and the focusing device can determine the corresponding refractive index change according to the target clarity threshold, and then determine the voltage change, and apply a voltage of a corresponding magnitude to the electro-optical modulation crystal 400 according to the voltage change rate, and adjust the image clarity to the target clarity threshold, thereby achieving focusing. Among them, the target clarity threshold includes but is not limited to a preset clarity threshold. The projection device can also compare the acquired image clarity with the preset clarity threshold in real time according to the image clarity acquired by the image sensor, determine the corresponding refractive index change, and then determine the voltage change, and apply a voltage of a corresponding magnitude to the electro-optical modulation crystal 400 according to the voltage change rate, and adjust the image clarity to the preset clarity threshold, thereby achieving automatic focusing.

[0072] The present invention acquires a real-time image on the screen, analyzes the image clarity in combination with an image processing algorithm, and determines the amount of refractive index change required for the current image clarity, thereby determining the voltage that needs to be applied to the conductive part of the electro-optical modulation crystal 400, and applying a voltage of a corresponding magnitude to the conductive part of the electro-optical modulation crystal 400. Compared with the traditional mechanical focusing method, the present invention changes the refractive index by applying a voltage to the electro-optical modulation crystal 400, thereby achieving automatic focusing, without the need for mechanical moving parts, and improving the focusing response speed; and utilizing the electro-optical effect of the electro-optical modulation crystal 400 to achieve stepless focusing, improve the limitation problem of the minimum driving distance, and improve the focusing accuracy. In addition, this solution replaces the mechanical focusing structure, improves the wear problem of mechanical parts, and extends the service life of the projection equipment. At the same time, the matching structure between the lens and the lens barrel is simplified, the demand for high-precision processing is reduced, and the processing and manufacturing costs are reduced.

[0073] It should be noted that the electro-optical modulation crystal 400 can be arranged at any position of the optical path to achieve a focusing effect of the picture.

[0074] Optionally, the electro-optic modulation crystal 400 is disposed between the light source and the second lens group 200 .

[0075] In this embodiment, a variety of optical elements can be arranged between the light source and the second lens group 200 to achieve different functions. The electro-optical modulation crystal 400 can replace some elements, such as elements related to polarization modulation, phase modulation and beam direction control.

[0076] Optionally, the electro-optic modulation crystal 400 is a galvanometer.

[0077] In this embodiment, a galvo mirror may be provided between the light source and the second lens group 200 for rapid scanning or deflection of light. The galvo mirror changes the direction of light by high-speed rotation or swinging, thereby achieving scanning or deflection of light. Figure 1 and Figure 3, from right to left, it includes a DMD chip 700, a protective glass 600, an equivalent prism 500, a galvanometer, a second lens group 200, an aperture 300 and a first lens group 100. The electro-optical modulation crystal 400 can replace the galvanometer to achieve rapid deflection of the light beam. The electro-optical modulation crystal 400 is placed between the light source and the second lens group 200 to ensure that the light path is correctly aligned. In practical applications, a suitable lens combination of the first lens group 100 and the second lens group 200 can be selected to ensure that the light beam can be correctly focused and deflected after passing through the electro-optical modulation crystal 400. During use, the image sensor captures the image of the light emitted by the light source after passing through the second lens group 200, the aperture 300 and the first lens group 100 and projected onto the screen, and automatically analyzes the clarity of the image in combination with the image processing algorithm, and outputs the clarity result of the image to the projection device, so that it can calculate the refractive index change that needs to be adjusted by the electro-optical modulation crystal 400 through software. When the refractive index change amount to be adjusted is known, the optical path of the light passing through the electro-optical modulation crystal 400 can be changed by changing the magnitude of the voltage applied to the electro-optical modulation crystal 400, thereby ultimately achieving the focusing of the image.

[0078] Optionally, the electro-optic modulation crystal 400 is disposed in the first lens group 100 or the second lens group 200 .

[0079] refer to Figure 1 and Figure 3 , when the electro-optical modulation crystal 400 is disposed in the first lens group 100, the first lens group 100 includes a first lens 10 with negative optical power, a second lens 20 with negative optical power, and a third lens 30 with positive optical power;

[0080] The electro-optic modulation crystal 400 is any one or more of the first lens 10 , the second lens 20 , and the third lens 30 . That is, the electro-optic modulation crystal 400 can replace the first lens 10 and / or the second lens 20 and / or the third lens 20 .

[0081] refer to Figure 2 and Figure 4 , when the electro-optical modulation crystal 400 is disposed in the first lens group 100, the first lens group 100 includes a fourth lens 40 with negative optical power and a fifth lens 50 with positive optical power;

[0082] The electro-optic modulation crystal 400 is any one or more of the fourth lens 40 and the fifth lens 50 . That is, the electro-optic modulation crystal 400 can replace the fourth lens 40 and / or the fifth lens 50 .

[0083] Optionally, refer to Figure 2 and Figure 4, when the electro-optical modulation crystal 400 is disposed in the second lens group 200, the second lens group 200 includes a sixth lens 60 with negative optical power, a seventh lens 70 with negative optical power, and an eighth lens 80 with positive optical power;

[0084] The electro-optical modulation crystal 400 is any one or more of the sixth lens 60, the seventh lens 70, and the eighth lens 80. That is, the electro-optical modulation crystal 400 can replace the sixth lens 60 and / or the seventh lens 70 and / or the eighth lens 80. Figure 4 As shown, the electro-optical modulation crystal 400 is disposed in the second lens group 200 , replacing the original eighth lens 80 .

[0085] In practical applications, the electro-optical modulation crystal 400 is arranged between the light source and the second lens group 200 to replace the optical element, or directly replace a lens in the first lens group 100 or the second lens group 200, which not only improves the focusing response speed and focusing accuracy of the projection device, but also enhances the practicality. Whether replacing the galvanometer or the lens, the electro-optical modulation crystal 400 can be flexibly configured according to specific needs to adapt to different application scenarios.

[0086] The present invention provides a focusing method, referring to Figure 5 The focusing method is applied to a projection device, the projection device includes the projection lens as described above, and a screen, the projection lens includes an electro-optical modulation crystal 400, which is used to modulate the light emitted by the light source and project it onto the screen, and the focusing method includes:

[0087] Step S100, obtaining the clarity of the image projected onto the screen;

[0088] In this embodiment, a high-resolution image sensor can be used to capture the image on the screen, and then the captured image is transmitted to an image processing system, for example, the captured image is transmitted to a main controller, so that the main controller determines the image clarity after performing image processing according to a preset image processing algorithm stored in an internal memory.

[0089] Optionally, the projection device further includes a distance sensor disposed at a location where the projection lens is located, and the calculation of the clarity of the image on the screen specifically includes:

[0090] Obtain the distance between the projection lens and the screen to calculate the clarity of the image on the screen according to the distance;

[0091] and / or, photographing the image on the screen to obtain a real-time image;

[0092] The real-time image is processed using a preset image processing algorithm to obtain the clarity of the image on the screen.

[0093] In this embodiment, the distance sensor can be implemented by ultrasonic sensors, laser sensors, infrared sensors, etc., and is used to measure the distance D between the projection lens and the screen. Then, the image clarity at this distance can be calculated according to optical formulas and preset projection parameters (such as focal length, aperture, etc.). Alternatively, a high-resolution image sensor (such as CMOS or CCD) can be used to capture the real-time image on the screen, and the captured image is transmitted to the main controller, so that the main controller determines the image clarity after performing image processing according to a preset image processing algorithm stored in the internal memory. The image processing algorithm includes image preprocessing (grayscale, denoising, etc.) and clarity evaluation (edge ​​detection, etc.).

[0094] Step S200, calculating the refractive index change amount that needs to be adjusted for the electro-optic modulation crystal 400 according to the image clarity and the preset clarity;

[0095] In this embodiment, the mapping relationship between the image clarity and the preset clarity can be preset in advance by the R&D personnel after a large number of experiments. For example, the refractive index change at different clarity is determined and stored in the memory in advance, so that the main controller first compares the image clarity actually calculated with the preset clarity. If the difference between the image clarity and the preset clarity is less than the preset clarity difference, it means that it is within the error tolerance range and will not affect the image clarity. At this time, there is no need to focus. If the difference between the image clarity and the preset clarity is greater than or equal to the preset clarity difference, it is necessary to focus and find the corresponding refractive index change. Optionally, the difference between different clarity and the preset clarity can be directly calculated, and the refractive index change corresponding to the different difference can be determined, so that the refractive index change corresponding to the difference can be found according to the difference between the image clarity actually calculated and the preset clarity.

[0096] Step S300, determining a voltage change according to the refractive index change, and applying a voltage of a corresponding magnitude to the conductive element of the electro-optic modulation crystal 400 according to the voltage change, so as to adjust the image clarity to a preset clarity.

[0097] It should be noted that the projection device includes a power supply, a conductive member, and an electrode. The power supply is electrically connected to the focusing device. The conductive member is arranged on the electro-optical modulation crystal 400, and the electrodes are electrically connected to the conductive member and the power supply, respectively. The focusing device is used to control the power supply to apply a voltage corresponding to the voltage change amount to the electro-optical modulation crystal 400 through the electrode.

[0098] In this embodiment, the conductive member can be a conductive transparent film, such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), carbon nanotubes (CNT), graphene, etc., and the conductive transparent film is prepared on the surface of the electro-optic modulation crystal 400 by deposition or coating technology. The electrode can be implemented by a metal electrode (such as gold, silver, copper) or other conductive materials. The power supply can be implemented by a DC voltage or an AC power supply.

[0099] Specifically, the projection device may further include a thyristor voltage regulator, which is used to receive the control signal output by the main controller and control the voltage applied to the electro-optical modulation crystal 400. Before using the projection device, it is necessary to connect the electrodes to the conductive transparent film and connect the power supply so that the main controller outputs the corresponding control signal to the thyristor voltage regulator after determining the voltage change, so that the thyristor voltage regulator applies a voltage of a corresponding magnitude to the conductive part of the electro-optical modulation crystal 400 according to the voltage change, adjusts the current image clarity, and controls the focusing amplitude through the thyristor voltage regulator, thereby realizing a fast and accurate focusing operation.

[0100] In this embodiment, the focusing method of the present invention can be applied to a focusing device of a projection device, wherein the focusing device can be implemented by a main controller, such as an MCU, a DSP (Digital Signal Process), a FPGA (Field Programmable Gate Array), a PLC, a SOC (SystemOn Chip), etc.

[0101] In combination with the contents of the above embodiments, a high-resolution image sensor can be used to capture the image on the screen, and then the captured image can be transmitted to the image processing system, for example, the captured image can be transmitted to the main controller, so that the main controller compares the image clarity with the preset clarity stored in the internal memory, and calculates the clarity difference, and then determines the refractive index change that needs to be adjusted based on the preset stored clarity difference and the refractive index change mapping table, and determines the voltage change based on the refractive index change, and calculates the voltage change that needs to be applied, so as to apply a voltage of corresponding magnitude to the conductive part of the electro-optical modulation crystal 400 according to the voltage change.

[0102] refer to Figure 6 , the determining of the voltage change according to the refractive index change specifically includes:

[0103] Step S310, obtaining the thickness of the electro-optical modulation crystal 400;

[0104] Step S320: Calculate the product of the refractive index change and the thickness of the electro-optic modulation crystal 400 to determine the voltage change according to the quotient of the product and the electro-optic coefficient.

[0105] In this embodiment, when the voltage applied to the electro-optic modulation crystal 400 changes, the refractive index of the electro-optic modulation crystal 400 changes accordingly. The mathematical description of the linear electro-optic effect is as follows:

[0106] △n=γE;

[0107] Where △n is the change in refractive index, γ is the electro-optic coefficient, and E is the applied electric field strength.

[0108] In the electro-optic modulation crystal 400, the relationship between the applied voltage V and the generated electric field E is:

[0109] E = V / d;

[0110] Wherein, d is the thickness of the electro-optic modulation crystal 400;

[0111] From the above formula, the relationship between the refractive index change △n and the voltage △V to be applied is as follows:

[0112] △V=d*△n / γ;

[0113] Therefore, in this embodiment, the main controller can calculate the product d*△n of the refractive index change and the thickness of the electro-optical modulation crystal 400 according to the known thickness of the electro-optical modulation crystal 400, and then calculate the quotient of the product and the electro-optic coefficient as the voltage change, wherein the electro-optical coefficient γ is a known quantity. In this way, when the refractive index change to be adjusted is known, the optical path of the light passing through the electro-optical modulation crystal 400 can be changed by changing the magnitude of the voltage applied to the electro-optical modulation crystal 400, thereby finally achieving the focus of the picture.

[0114] Optionally, after applying a voltage of a corresponding magnitude to the conductive element of the electro-optic modulation crystal 400 according to the voltage variation, the focusing method further includes:

[0115] The step of calculating the definition of the image on the screen is re-executed until the definition of the image is adjusted to a preset definition.

[0116] In this embodiment, after determining the voltage change, the main controller outputs a corresponding control signal to the thyristor voltage regulator, so that the thyristor voltage regulator applies a voltage of corresponding magnitude to the conductive part of the electro-optical modulation crystal 400 according to the voltage change, thereby adjusting the current image clarity. During this process, the image sensor or distance sensor is still working, so that the main controller can obtain the results output by the image sensor or distance sensor in real time, and calculate the clarity of the image on the screen based on the results, thereby realizing a fast focusing process. It can be understood that in order to determine the accuracy of focusing, after applying a voltage of corresponding magnitude to the conductive part of the electro-optical modulator crystal 400 according to the voltage change, the main controller recalculates the image clarity on the screen, and determines the relationship between the image clarity and the preset emotional level. If the current image clarity does not reach the better emotional level, the refractive index change that needs to be adjusted for the electro-optical modulator crystal 400 is calculated based on the image clarity and the preset clarity, and then the voltage change is determined, so that a voltage of corresponding magnitude is applied to the conductive part of the electro-optical modulator crystal 400 according to the voltage change, to achieve gradual focusing until the current image clarity is adjusted to the preset clarity, thereby achieving a better focusing effect.

[0117] It should be noted that in DLP projection optical machines, galvanometer devices are often used to improve image resolution. The basic principle is to use human visual persistence to quickly move and shake a piece of flat glass to improve image resolution. In this embodiment, the electro-optical modulation crystal 400 material can be used to replace the flat glass in the galvanometer, and its refractive index can be changed by voltage, thereby changing the optical path of light passing through the lens, and finally achieving image focusing without affecting the use effect of the galvanometer.

[0118] Specifically, lithium niobate (LiNbO3) can be selected as the material of the electro-optical modulation crystal 400, which is used as a focusing optical element. It is fixed in the optical path to ensure that the crystal is perpendicular to the optical axis and can withstand a certain temperature and vibration to avoid being affected by vibration, thereby improving the reliability of the work. Figure 3 , Figure 3This is a schematic diagram of a DLP lens that uses an electro-optical modulation crystal 400 as a galvanometer material. The projection distance of the lens is designed to be 0.5m-3m, and the standard projection distance is 1.6m. Among them, the projection distance and the standard projection distance can be set in advance by the R&D personnel. When the projection distance is 1.6m, no voltage needs to be applied to the galvanometer (electro-optical modulation crystal 400). When the projection distance changes and focusing is required, that is, when the current projection distance is not equal to 1.6m, the image projected on the screen is captured by the image sensor, the main controller analyzes the image clarity, and calculates the refractive index change that needs to be adjusted by the electro-optical modulation crystal 400 through a preset image processing algorithm, and then determines the required voltage change. After sending a voltage change instruction (control signal) to control the focus, the image sensor continuously monitors the clarity of the image after focusing, and feeds back to the main controller for voltage fine-tuning until the target focusing effect is achieved.

[0119] refer to Figure 4 , Figure 4 This is a schematic diagram of a DLP lens using an electro-optical modulation crystal 400 as a lens material. When designing the lens optics, the material of a lens is set to potassium titanium phosphate (KTP) crystal, such as the eighth lens 80, and the refractive index of the eighth lens 80 is used as a variable to analyze and optimize the imaging effect at different projection distances. If the projection distance designed for the projection lens is 0.2-2m, the standard projection distance is 1m. When the projection distance is 1m, no voltage needs to be applied to the eighth lens 80. When the projection distance changes and focusing is required, the image projected on the screen is captured by the image sensor, the main controller analyzes the image clarity, and calculates the refractive index change of the electro-optical modulation crystal 400 that needs to be adjusted through the preset image processing algorithm, and then determines the required voltage change. After sending the voltage change instruction (control signal) to control the focus, the image sensor continuously monitors the image clarity after focusing, and feeds back to the main controller for voltage fine-tuning until the target focusing effect is achieved.

[0120] In actual application, the projection device can manually set the target clarity threshold according to the user, and the focusing device can determine the corresponding refractive index change according to the target clarity threshold, and then determine the voltage change, and apply a voltage of a corresponding magnitude to the electro-optical modulation crystal 400 according to the voltage change rate, and adjust the image clarity to the target clarity threshold, thereby achieving focusing. Among them, the target clarity threshold includes but is not limited to a preset clarity threshold. The projection device can also compare the acquired image clarity with the preset clarity threshold in real time according to the image clarity acquired by the image sensor, determine the corresponding refractive index change, and then determine the voltage change, and apply a voltage of a corresponding magnitude to the electro-optical modulation crystal 400 according to the voltage change rate, and adjust the image clarity to the preset clarity threshold, thereby achieving automatic focusing. In this way, the focusing method proposed by the present invention replaces the mechanical transmission device in the traditional solution, and can focus instantly by adjusting the voltage, and the response time is shorter. At the same time, continuous zooming is achieved. In this way, the focusing response speed and focusing accuracy are improved, and the design cost is reduced.

[0121] The present invention also proposes a focusing device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of any one of the above-mentioned focusing methods.

[0122] It is worth noting that since the focusing device of the present invention is based on the above-mentioned focusing method, the embodiments of the focusing device of the present invention include all technical solutions of all embodiments of the above-mentioned focusing method, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0123] The present invention further proposes a storage medium, which is a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, the steps of the focusing method described in any one of the above items are implemented.

[0124] It is worth noting that, since the storage medium of the present invention is based on the above-mentioned focusing method, the embodiments of the storage medium of the present invention include all technical solutions of all embodiments of the above-mentioned focusing method, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0125] The present invention also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the steps of any one of the focusing methods described above are implemented.

[0126] It is worth noting that since the computer program product of the present invention is based on the above-mentioned focusing method, the embodiments of the computer program product of the present invention include all technical solutions of all embodiments of the above-mentioned focusing method, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0127] The present invention further provides a projection device, comprising any one of the projection lenses described above, and the focusing device described above.

[0128] Optionally, the projection device includes:

[0129] A power supply electrically connected to the focusing device;

[0130] A conductive member, wherein the conductive member is disposed on the electro-optic modulation crystal 400;

[0131] Electrodes, the electrodes are electrically connected to the conductive member and the power supply respectively;

[0132] The focusing device is used to control the power supply to apply a voltage corresponding to the voltage change amount to the electro-optical modulation crystal 400 through the electrode.

[0133] In this embodiment, the conductive member can be a conductive transparent film, such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), carbon nanotubes (CNT), graphene, etc., and the conductive transparent film is prepared on the surface of the electro-optic modulation crystal 400 by deposition or coating technology. The electrode can be implemented by a metal electrode (such as gold, silver, copper) or other conductive materials. The power supply can be implemented by a DC voltage or an AC power supply.

[0134] Specifically, the projection device may further include a thyristor voltage regulator, which is used to receive the control signal output by the main controller and control the voltage applied to the electro-optical modulation crystal 400. Before using the projection device, it is necessary to connect the electrodes to the conductive transparent film and connect the power supply so that the main controller outputs the corresponding control signal to the thyristor voltage regulator after determining the voltage change, so that the thyristor voltage regulator applies a voltage of a corresponding magnitude to the conductive part of the electro-optical modulation crystal 400 according to the voltage change, and adjusts the current image clarity, that is, controls the focus amplitude through the thyristor voltage regulator, thereby realizing a fast and accurate focus operation.

[0135] In practical applications, the electro-optical modulation crystal 400 is used to replace the traditional mechanical focusing method to improve the focusing response speed; and the electro-optical effect of the electro-optical modulation crystal 400 is used to achieve stepless focusing, improve the limitation of the minimum driving distance, and improve the focusing accuracy.

[0136] It is worth noting that, since the projection device of the present invention includes the above-mentioned projection lens and / or focusing device, the embodiments of the projection device of the present invention include all technical solutions of all embodiments of the above-mentioned projection lens and / or focusing device, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0137] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or direct / indirect applications in other related technical fields, under the inventive concept of the present invention are included in the patent protection scope of the present invention.

Claims

1. A projection lens, characterized in that: The projection lens comprises a first lens group, an aperture, and a second lens group arranged in sequence along a horizontal direction; and, A light source is disposed on one side of the second lens group, and light emitted by the light source passes through the second lens group, the aperture and the first lens group in sequence to form a light path; An electro-optical modulation crystal is arranged in the optical path.

2. The projection lens according to claim 1, wherein: The electro-optic modulation crystal is disposed between the light source and the second lens group.

3. The projection lens according to claim 2, wherein: The electro-optical modulation crystal is a galvanometer.

4. The projection lens according to claim 1, wherein: The electro-optic modulation crystal is disposed in the first lens group or the second lens group.

5. The projection lens according to claim 4, wherein: When the electro-optical modulation crystal is arranged in the first lens group, the first lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power; The electro-optical modulation crystal is any one or more of the first lens, the second lens, and the third lens.

6. The projection lens according to claim 4, wherein: When the electro-optical modulation crystal is arranged in the first lens group, the first lens group includes a fourth lens with negative optical power and a fifth lens with positive optical power; The electro-optical modulation crystal is any one or more of the fourth lens and the fifth lens.

7. The projection lens according to claim 4, wherein: When the electro-optical modulation crystal is arranged in the second lens group, the second lens group includes a sixth lens with negative optical power, a seventh lens with negative optical power and an eighth lens with positive optical power; The electro-optical modulation crystal is any one or more of the sixth lens, the seventh lens, and the eighth lens.

8. The projection lens according to any one of claims 1 to 7, characterized in that: The electro-optic modulation crystal includes any one of potassium titanate crystal, lithium niobate crystal and gallium arsenide crystal.

9. A focusing method, characterized in that: Applied to a projection device, the projection device comprises a projection lens as claimed in any one of claims 1 to 8, and a screen, the projection lens comprises an electro-optical modulation crystal for modulating the light emitted by the light source and projecting it onto the screen, and the focusing method comprises: Get the clarity of the image projected onto the screen; Calculating the refractive index change amount that needs to be adjusted for the electro-optical modulation crystal according to the image clarity and the preset clarity; The voltage change is determined according to the refractive index change, and a voltage of a corresponding magnitude is applied to the conductive element of the electro-optical modulation crystal according to the voltage change, so as to adjust the image clarity to a preset clarity.

10. The focusing method according to claim 9, characterized in that: Determining the voltage change amount according to the refractive index change amount specifically includes: Obtaining the thickness of the electro-optical modulation crystal; The product of the refractive index variation and the thickness of the electro-optic modulation crystal is calculated to determine the voltage variation according to the quotient of the product and the electro-optic coefficient.

11. The focusing method according to claim 9, characterized in that: After applying a voltage of a corresponding magnitude to the conductive element of the electro-optical modulation crystal according to the voltage variation, the focusing method further comprises: The step of calculating the definition of the image on the screen is re-executed until the definition of the image is adjusted to a preset definition.

12. The focusing method according to claim 9, characterized in that: The projection device further includes a distance sensor disposed at the location of the projection lens, and the definition of the image on the screen is calculated specifically including: Obtain the distance between the projection lens and the screen to calculate the clarity of the image on the screen according to the distance; and / or, photographing the image on the screen to obtain a real-time image; The real-time image is processed using a preset image processing algorithm to obtain the clarity of the image on the screen.

13. A focusing device, characterized in that: The focusing device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the focusing method according to any one of claims 9 to 12.

14. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the focusing method according to any one of claims 9 to 12 are implemented.

15. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the steps of the focusing method according to any one of claims 9 to 12 are implemented.

16. A projection device, characterized in that: The projection device comprises the projection lens according to any one of claims 1 to 8, and the focusing device according to claim 13.

17. The projection device according to claim 16, characterized in that: The projection device comprises: A power supply electrically connected to the focusing device; A conductive member, the conductive member being arranged on the electro-optical modulation crystal; Electrodes, the electrodes are electrically connected to the conductive member and the power supply respectively; The focusing device is used to control the power supply to apply a voltage corresponding to the voltage change amount to the electro-optical modulation crystal through the electrode.

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