Projection optical assembly for light control based on LED and projection device

Abstract

The invention discloses an LED-based light-operated projection optical assembly and a projection device. The projection optical assembly comprises an LED light source, an incident polaroid, a liquid crystal glass body, an imaging polaroid, a Fresnel lens and a projection lens which are arranged in sequence. And the at least one photoelectric sensor is fixedly arranged on the side edge of the Fresnel lens, the projection lens or the glass sheet. The invention further discloses a projection device for light control based on the LED, a photoelectric sensor is arranged on a post-stage optical device for image output of the imager, and the photoelectric sensor is used for completing image brightness detection processing so as to control the LED light source power. Radial escape light emitted by the Fresnel lens, the projection lens or the glass sheet is sensed in real time through the photoelectric sensor, an electric signal is output, and the power of the LED light source is adjusted through the intensity of the electric signal output by the photoelectric sensor. The problem that an existing LCD projection device cannot enable the output light intensity of the LED light source to change along with the image brightness is effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of projection technology, and in particular to a projection optical component and a projection device for light control based on LED. Background Art

[0002] In the prior art, the projection device using LCD imaging has a constant luminous power of its LED illumination light source; while the brightness of the image to be displayed by the LCD imager is constantly changing. For example, if part or all of the image becomes dark, the light utilization in these dark image areas is small, and the excess light will be converted into heat in the light valve, which is extremely detrimental to the stable operation of the LCD liquid crystal light valve and may even greatly shorten the service life of the projection device.

[0003] A single-chip LCD projection device is now used as an example for explanation: a single-chip LCD projection device generally includes an LED light source, an incident polarizer, a liquid crystal glass body, an imaging polarizer, a Fresnel lens and a projection lens in sequence; in order to prevent dust from entering, the LED light source, the incident polarizer, the liquid crystal glass body, the imaging polarizer, the Fresnel lens and the projection lens are to be treated as a closed space to prevent external dust from contaminating the optical devices, and this closed space is called a screen room; however, the screen room space adopts a high-standard closed method, and in this closed space, due to the incident polarizer, the liquid crystal glass body and the imaging polarizer, more than 90% of the incident light will be converted into heat in the closed screen room; on the one hand, the polarizer is basically made of polymer resin materials, and its light radiation resistance and temperature resistance are not high. It is very easy to be damaged by long-term exposure to excessive light and excessive heat; on the other hand, there are complex electronic devices for liquid crystal pixel control in the liquid crystal glass body. Generally, when the surface temperature of the glass body is greater than 80°C, these electronic devices will lose their function and the liquid crystal screen will be completely blocked from light, resulting in a black screen and no imaging. Therefore, the LCD projection device in the prior art cannot make the output light intensity of the LED light source change with the image brightness, thereby accelerating the accumulation of heat in the screen room; therefore, a projection optical component and a projection device based on LED light control are provided to solve the above problem. Summary of the invention

[0004] One of the purposes of the present invention is to provide a projection optical component and a projection device based on LED light control, so as to solve the problem that the existing LCD projection device cannot make the output light intensity of the LED light source change with the image brightness.

[0005] The projection optical component and projection device based on LED light control of the present invention can be realized by the following technical solutions:

[0006] The present invention discloses a projection optical component for light control based on LED, comprising an LED light source, an incident polarizer, a liquid crystal glass body, an imaging polarizer, a Fresnel lens and a projection lens which are arranged in sequence; at least one photoelectric sensor is fixedly arranged on the side of the Fresnel lens or the projection lens, the photoelectric sensor senses radial escape light emitted by the Fresnel lens or the projection lens in real time and outputs an electrical signal, and the power of the LED light source is adjusted by the strength of the electrical signal output by the photoelectric sensor.

[0007] The present invention discloses a projection optical component based on LED for light control, comprising an LED light source, an incident polarizer, a liquid crystal glass body, an imaging polarizer, a Fresnel lens and a projection lens arranged in sequence;

[0008] It also includes a glass sheet, which is arranged between the imaging polarizer and the Fresnel lens, or between the Fresnel lens and the projection lens; at least one photoelectric sensor is fixedly arranged on the side of the glass sheet, and the photoelectric sensor senses the radial escape light emitted by the glass sheet in real time and outputs an electrical signal, and the power of the LED light source is adjusted by the strength of the electrical signal output by the photoelectric sensor.

[0009] In one embodiment, the LED light source, the incident polarizer, the liquid crystal glass body, the imaging polarizer, and the Fresnel lens are sequentially arranged in a screen chamber, and the screen chamber is a hollow sealed cavity.

[0010] In one embodiment, a screen room temperature sensor is disposed in the screen room, and the screen room temperature sensor detects the temperature in the screen room in real time.

[0011] In one embodiment, the incident polarizer is made of a polymer resin material that only allows light waves with a single vibration direction to pass through.

[0012] In one embodiment, the imaging polarizer is also made of a polymer resin material that only allows light waves perpendicular to the polarization direction of the incident polarizer to pass through.

[0013] A projection device based on LED light control of the present invention comprises the above-mentioned projection optical component, light control board, power supply and LED driving board and main control board; the main control board is electrically connected to the liquid crystal glass body, the light control board, the power supply and LED driving board respectively; the light control board is electrically connected to at least one of the photoelectric sensors and the screen room temperature sensor respectively; the power supply and LED driving board is electrically connected to the LED light source.

[0014] In one embodiment, the light control panel includes a signal amplification circuit, a hysteresis circuit, a temperature detection output circuit, a dark scene power setting circuit and a voltage control circuit; the photoelectric sensor is electrically connected to the signal amplification circuit and the hysteresis circuit in sequence; the screen room temperature sensor is electrically connected to the temperature detection output circuit; the hysteresis circuit, the temperature detection output circuit and the dark scene power setting circuit are electrically connected to the voltage control circuit respectively.

[0015] In one embodiment, the voltage control circuit synthesizes the voltage signal output by the photoelectric sensor and processed by the signal amplification circuit, the hysteresis circuit, the voltage signal set by the dark scene power setting circuit, and the power limiting voltage signal generated by the temperature detection output circuit, and generates a voltage signal for pulse width modulation of the subsequent PWM and transmits it to the main control board. The main control board generates a PWM signal of a corresponding duty cycle according to the current state of the image, and then controls the output power of the LED light source through the power supply and LED driver board.

[0016] In one embodiment, the PWM signal includes a duty cycle signal that changes with the brightness of the image, and also includes a minimum set power when the image is dark and a LED light source power limiting signal when the temperature in the screen room exceeds an upper limit.

[0017] Compared with the prior art, the beneficial effects of the projection optical component and projection device based on LED light control of the present invention are as follows:

[0018] The present invention discloses a projection optical component and a projection device based on LED light control, which senses radial escape light emitted by a Fresnel lens, a projection lens or a glass sheet in real time and outputs an electrical signal through a photoelectric sensor, and adjusts the power of an LED light source according to the strength of the electrical signal output by the photoelectric sensor, thereby effectively solving the problem that the output light intensity of an LED light source cannot change with the image brightness in an existing LCD projection device, so that within a certain time period, the median brightness of the projection is used as the reference, the human eye perception of the brightness of the image is magnified, and a visual impact effect is more easily obtained;

[0019] The present invention discloses an LED-based light control projection optical component and a projection device. The LED light source power is correspondingly reduced under various levels of dark scene images, thereby reducing the heat generated by light waves, suppressing the accumulation of temperature in a liquid crystal screen room to a certain extent, and effectively reducing the average power during projection operation, thereby reducing the equilibrium temperature of the screen room after heat accumulation; at the same time, within a certain period of time, the time average value of the LED light source power that changes with the image is lower than the maximum value, reducing the equilibrium temperature of the screen room, as well as the light radiation of the incident polarizer, the liquid crystal glass body and the imaging polarizer, which is beneficial to improving the performance brightness of the projection device and improving the service life of the projection device to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a structural schematic diagram of a first embodiment of a projection optical component for light control based on LED according to the present invention;

[0022] Figure 2 It is a structural schematic diagram of a second embodiment of a projection optical component for light control based on LEDs according to the present invention;

[0023] Figure 3 It is a structural schematic diagram of a third embodiment of a projection optical component for light control based on LEDs according to the present invention;

[0024] Figure 4 It is a structural schematic diagram of a fourth embodiment of a projection optical component for light control based on LEDs according to the present invention;

[0025] Figure 5 It is a schematic diagram of the connection structure of a projection device based on LED light control of the present invention, including a photoelectric sensor and a screen room temperature sensor;

[0026] Figure 6 yes Figure 5 The signal processing logic diagram of the photoelectric sensor and screen room temperature sensor is shown.

[0027] Markings in the figure: 10, projection optical component; 11, LED light source; 12, incident polarizer; 13, liquid crystal glass; 14, imaging polarizer; 15, Fresnel lens; 16, projection lens; 17, photoelectric sensor; 18, glass sheet; 19, screen room temperature sensor; 20, light control board; 21, signal amplification circuit; 22, hysteresis circuit; 23, temperature detection output circuit; 24, dark scene power setting circuit; 25 voltage control circuit; 30, power supply and LED driver board; 40, main control board. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0030] First embodiment

[0031] See also Figure 1As shown, in this embodiment, a projection optical component 10 based on LED light control of the present invention mainly includes an LED light source 11, an incident polarizer 12, a liquid crystal glass body 13, an imaging polarizer 14, a Fresnel lens 15, a projection lens 16 and a photoelectric sensor 17 which are arranged in sequence; the LED light source 11, the incident polarizer 12, the liquid crystal glass body 13, the imaging polarizer 14, the Fresnel lens 15 and the projection lens 16 are arranged in sequence; the light emitted by the LED light source 11 is collimated illumination light, which is light in a full vibration direction, that is, the light contains half of the light waves of transverse vibration and vertical vibration; the incident polarizer 12 is made of a polymer resin material, which only allows light waves of a single vibration direction to pass through, and the blocked light waves will generate heat in the incident polarizer 12; the liquid crystal glass body 13 is a key component of the LCD imager, which has the function of twisting a part of the incident polarized light passing through the incident polarizer 12 into image light of another vibration direction according to the brightness and color requirements of the image pixels, and the non-image light that is not twisted Part of the image light is converted into heat in the liquid crystal glass body 13, and the rest of the light maintains the incident polarization direction and passes through the liquid crystal glass body 13 to be mixed with the image light for output. The liquid crystal glass body 13 processes a frame of image in units of pixels, and the transmittance of the image light is negatively correlated with the high and low values ​​of the temperature within the allowable temperature range of the liquid crystal glass body 13, that is, the higher the temperature, the lower the transmittance of the image light; the imaging polarizer 14 is made of polymer resin material, which only allows light waves perpendicular to the polarization direction of the incident polarizer 12 to pass, that is, to pass the image light, and blocks the light that is not twisted from generating heat in the imaging polarizer 14; the function of the Fresnel lens 15 is to converge the image light to adapt to the smaller-diameter projection lens 16; the projection lens 16 is an optical component for projecting the image light; the photoelectric sensor 17 is fixedly arranged on the side of the Fresnel lens 15, and it senses the radial escape light emitted by the Fresnel lens 15 in real time and outputs an electrical signal, and the power of the LED light source 11 is adjusted by the strength of the electrical signal output by the photoelectric sensor 17. In other embodiments, a plurality of photoelectric sensors 17 are respectively fixedly arranged on the sides of the Fresnel lens 15, and the plurality of photoelectric sensors cooperate to sense the radially escaped light emitted by the Fresnel lens 15 in real time and output an electrical signal. Specifically, the photoelectric sensor 17 adopts the existing conventional technology, so its specific structure and working process are not described in detail here, as long as it meets the requirements of this application.

[0032] Specifically, radial escape light is the useless light that optical devices will inevitably generate, which is the escape light at 90 degrees to the incident light of the optical device; the reason for the generation of radial escape light is mainly based on the following optical principles: one is the medium surface reflection principle: when light is emitted from a medium of one density to a medium of another density, part of the light will be reflected; the other is the total reflection principle: when light is emitted from a dense medium to a sparse medium, total reflection will occur at a certain incident angle. When the angle does not meet the conditions for total reflection, reflection will still occur, but the reflected light is relatively small.

[0033] The radial outgoing light generated by the light beam formed by a certain pixel is proportional to the brightness of the pixel light beam. It can be expressed as:

[0034] Radial outgoing light intensity Sn=Ln*K --- (1)

[0035] Sn is the radial escape light intensity of the nth pixel, Ln is the light intensity of the light beam at the pixel, and K is the coefficient of the radial escape light generated by the light beam formed by the pixel in the plane mirror, which is generally between 0.02-0.08. It can be seen that Sn is very weak.

[0036] The light beam formed by each pixel contains rich multi-angle light and is symmetrical in the radial direction. Therefore, radial escape light can be detected at any position around the optical device; the full set of radial escape light of pixel light in the image: taking a 1080 resolution LCD screen as an example, there are 1920X1080=6220800 full-color pixels distributed on the screen. Under the irradiation of collimated light, after passing through these pixels, the outgoing light corresponding to the brightness of the pixel point of the entire image is formed. A total of L1, L2, L3...L6220800 light beams enter the optical device at the same time, constituting all the incident light of the optical device, and each incident light will form a radial light waveguide escape light on any side of the optical device. The full-pixel radial escape light intensity S of these escape lights can be expressed as:

[0037] Radial light emission intensity

[0038] K is the waveguide attenuation coefficient, where the waveguide transmission loss is ignored;

[0039] Therefore, almost the same radially emitted light after integration of all pixels can be observed on any side of the plane mirror. In the above expressions (1) and (2), the pixel points will show brightness changes due to the imaging position, and the sides of the optical device will show proportional brightness changes. The more dark scenes there are, the weaker the intensity of the radially emitted light will be; the more bright scenes there are, the stronger the intensity of the radially emitted light will be.

[0040] Specifically, the photoelectric sensor 17 can sense the intensity of radially escaped light in real time, which represents the brightness of the LCD image under a certain illumination light intensity, that is, the ratio of the area occupied by the bright scene image, the dark scene image and the bright-dark transition image in one frame of image; when there are more dark scene images in one frame (actually multiple frames of continuous images), the human eye's requirement for the brightness of the entire image will be reduced, and conversely, when there are more bright scene images in one frame of image, the human eye's requirement for the brightness of the entire image will be increased; therefore, the power of the LED light source 11 can be controlled according to the intensity of the photoelectric signal output by the photoelectric sensor 17, that is, the electrical signal output by the photoelectric sensor 17 that senses the radially escaped light in real time is processed and then controlled. The power of the D light source 11 is controlled in a follow-up manner, so that when a bright scene image is displayed, the power of the LED light source 11 is increased in time to make the image brightness higher; similarly, the corresponding low power of the LED light source 11 is adapted in different dark scenes; when a bright scene image is displayed, the output power of the LED light source 11 is increased so that more light passes through the liquid crystal glass body 13, thereby increasing the output brightness and improving the brightness index under a safe working state; in dark scene images at various levels, the power of the LED light source 11 is reduced accordingly, thereby reducing the heat generated by the blocked light waves. This heat is the main source of heat in the screen room and has a cumulative effect, which is the main reason for limiting the projection brightness.

[0041] See also Figure 1 and Figure 5 As shown, in this embodiment, the LED light source 11, the incident polarizer 12, the liquid crystal glass body 13, the imaging polarizer 14, and the Fresnel lens 15 are sequentially arranged in the screen chamber. The screen chamber is a hollow sealed cavity, in which a screen chamber temperature sensor 19 is arranged. The screen chamber temperature sensor 19 detects the temperature of the screen chamber in real time.

[0042] Second embodiment

[0043] See also Figure 2 As shown, in this embodiment, a projection optical component 10 based on LED light control of the present invention mainly includes an LED light source 11, an incident polarizer 12, a liquid crystal glass body 13, an imaging polarizer 14, a Fresnel lens 15, a projection lens 16 and a photoelectric sensor 17 which are arranged in sequence; the LED light source 11, the incident polarizer 12, the liquid crystal glass body 13, the imaging polarizer 14, the Fresnel lens 15 and the projection lens 16 are arranged in sequence; the photoelectric sensor 17 is fixedly arranged on the side of the projection lens 16, and it senses the radial escape light emitted by the projection lens 16 in real time and outputs an electrical signal, and the power of the LED light source 11 is adjusted by the strength of the electrical signal output by the photoelectric sensor 17. In other embodiments, multiple photoelectric sensors 17 can also be fixedly arranged on the side of the projection lens 16, and the multiple photoelectric sensors 17 cooperate to sense the radial escape light emitted by the projection lens 16 in real time and output an electrical signal.

[0044] Third embodiment

[0045] See also Figure 3 As shown, in this embodiment, a projection optical component 10 based on LED light control of the present invention mainly includes an LED light source 11, an incident polarizer 12, a liquid crystal glass body 13, an imaging polarizer 14, a Fresnel lens 15, a projection lens 16, a photoelectric sensor 17 and a glass sheet 18 which are arranged in sequence; the LED light source 11, the incident polarizer 12, the liquid crystal glass body 13, the imaging polarizer 14, the Fresnel lens 15 and the projection lens 16 are arranged in sequence; the glass sheet 18 is arranged between the imaging polarizer 14 and the Fresnel lens 15; the photoelectric sensor 17 is fixedly arranged on the side of the glass sheet 18, and it senses the radial escape light emitted by the glass sheet 18 in real time and outputs an electrical signal, and the power of the LED light source 11 is adjusted by the strength of the electrical signal output by the photoelectric sensor 17. In other embodiments, multiple photoelectric sensors 17 can also be fixedly arranged on the sides of the glass sheet 18, and the multiple photoelectric sensors 17 cooperate to sense the radial escape light emitted by the glass sheet 18 in real time and output an electrical signal.

[0046] Fourth embodiment

[0047] See also Figure 4 As shown, in this embodiment, a projection optical component 10 based on LED light control of the present invention mainly includes an LED light source 11, an incident polarizer 12, a liquid crystal glass body 13, an imaging polarizer 14, a Fresnel lens 15, a projection lens 16, a photoelectric sensor 17 and a glass sheet 18 which are arranged in sequence; the LED light source 11, the incident polarizer 12, the liquid crystal glass body 13, the imaging polarizer 14, the Fresnel lens 15 and the projection lens 16 are arranged in sequence; the glass sheet 18 is arranged between the Fresnel lens 15 and the projection lens 16; the photoelectric sensor 17 is fixedly arranged on the side of the glass sheet 18, and it senses the radial escape light emitted by the glass sheet 18 in real time and outputs an electrical signal, and the power of the LED light source 11 is adjusted by the strength of the electrical signal output by the photoelectric sensor 17. In other embodiments, multiple photoelectric sensors 17 can also be fixedly arranged on the sides of the glass sheet 18, and the multiple photoelectric sensors 17 cooperate to sense the radial escape light emitted by the glass sheet 18 in real time and output an electrical signal.

[0048] See also Figure 1 , Figure 5 and Figure 6As shown, in this embodiment, a projection device based on LED light control of the present invention includes a projection optical component 10, a light control board 20, a power supply and LED driving board 30 and a main control board 40; the light control board 20 is electrically connected to the photoelectric sensor 17, the screen room temperature sensor 19, and the main control board 40, respectively, and it receives the electrical signals transmitted by the photoelectric sensor 17 and the screen room temperature sensor 19, processes them and transmits them to the main control board 40; the power supply and LED driving board 30 are electrically connected to the LED light source 11 and the main control board 40, respectively, and it supplies power to the LED light source 11 and the main control board 40, respectively, and at the same time receives the electrical signal of the main control board 40 to control the output power of the LED light source 11 in real time; the main control board 40 is electrically connected to the liquid crystal glass body 13, the light control board 20, the power supply and LED driving board 30, respectively, and at the same time controls the output power of the LED light source 11 through the power supply and LED driving board 30. Specifically, after the main control board 40 issues a power-on command, the light emitted by the LED light source 11 passes through the incident polarizer 12, the liquid crystal glass body 13, the imaging polarizer 14, the Fresnel lens 15, and the projection lens 16 in sequence to project an image; at this time, the photoelectric sensor 17 senses the intensity of the radial escape light emitted by the Fresnel lens 15 in real time, and transmits the brightness electrical signal of each frame of the image to the light control board 20 for processing. The light control board 20 transmits the processed electrical signal to the main control board 40. The main control board 40 generates a PWM signal corresponding to the duty cycle according to the current state of the image, and controls the output power of the LED light source 11 through the power supply and the LED driving board 30, thereby realizing real-time regulation of the power of the LED light source 11.

[0049] See also Figure 5 and Figure 6As shown, specifically, the light control board 20 includes a signal amplifying circuit 21, a hysteresis circuit 22, a temperature detection output circuit 23, a dark scene power setting circuit 24 and a voltage control circuit 25; the photoelectric sensor 17 is electrically connected to the signal amplifying circuit 21 and the hysteresis circuit 22 in sequence. Since the electrical signal output by the photoelectric sensor 17 inductively senses the radial escape light emitted by the Fresnel lens 15 is very weak, it needs to be amplified by the signal amplifying circuit 21 before entering the subsequent circuit; the amplified electrical signal is processed by the hysteresis circuit 22 to convert the electrical signal into: when the brightness of the image suddenly increases, the signal voltage increases almost without delay, exceeding the range of human eye changes; when the brightness of the image suddenly increases, the signal voltage increases with the signal voltage ... When the signal voltage is reduced, it must go through a certain delay time. During this period of time, the signal voltage slowly decreases linearly before following the change in the brightness of the current image. The purpose of this is to prevent the human eye from perceiving the power change of the LED light source 11, and only consider it as a normal change in the brightness of the image; the screen room temperature sensor 19 is electrically connected to the temperature detection output circuit 23, and the temperature detection output circuit 23 converts the temperature in the screen room sensed by the screen room temperature sensor 19 in real time into an electrical signal output; the hysteresis circuit 22, the temperature detection output circuit 23, and the dark scene power setting circuit 24 are electrically connected to the voltage control circuit 25 respectively, and the dark scene power setting circuit 24 sets the maximum value as needed. The power of the LED light source 11 is controlled at this point or below so that the power of the LED light source 11 is no longer controlled following the induction change of the photoelectric sensor 17 to ensure the basic brightness in the dark scene; it is generally set at about 40% of the maximum output power of the LED light source 11; when the temperature detection output circuit 23 detects that the temperature of the screen room has reached a preset value, the power of the LED light source 11 begins to be limited. The higher the temperature in the screen room, the greater the drop in the maximum power limit. When the high temperature in the screen room is released, the restriction is released; the voltage control circuit 25 receives the voltage signal of the photoelectric sensor 17 and processes it in turn through the signal amplification circuit 21 and the hysteresis circuit 22, the dark scene power The voltage signal set by the setting circuit 24 and the power limiting voltage signal generated by the temperature detection output circuit 23 are synthesized to generate a voltage signal for pulse width modulation of the subsequent PWM and transmit it to the main control board 40. The main control board 40 generates a PWM signal with a corresponding duty cycle according to the current state of the image, and controls the output power of the LED light source 11 through the power supply and the LED driving board 30, thereby realizing real-time regulation of the power of the LED light source 11; specifically, the PWM signal includes a duty cycle signal that changes accordingly with the brightness of the image, and also includes the minimum set power when the image is dark and the power limiting signal of the LED light source 11 when the temperature in the screen room exceeds the upper limit.

[0050] It should be noted that the specific working process of the projection optical component and projection device based on LED light control of the present invention is as follows: the photoelectric sensor 17 senses the radial escape light emitted by the projection lens 16, the photoelectric sensor 17 or the glass sheet 18 in real time and converts the optical signal into an electrical signal. The electrical signal converted by the photoelectric sensor 17 is processed by the signal amplification circuit 21 and the hysteresis circuit 22 in sequence. At the same time, the temperature detection output circuit 23 converts the temperature in the screen room sensed in real time by the screen room temperature sensor 19 into an electrical signal output. The dark scene power setting circuit 24 sets the LED light source 11 to the darkest image. The voltage control circuit 25 synthesizes the voltage signal input from the photoelectric sensor 17 and processed by the signal amplification circuit 21 and the hysteresis circuit 22 in sequence, the voltage signal set by the dark scene power setting circuit 24, and the power limit voltage signal generated by the temperature detection output circuit 23, and generates a voltage signal for pulse width modulation of the subsequent PWM and transmits it to the main control board 40. The main control board 40 generates a PWM signal of a corresponding duty cycle according to the current state of the image, and controls the output power of the LED light source 11 through the power supply and the LED driving board 30, thereby realizing real-time regulation of the power of the LED light source 11.

[0051] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A projection optical component based on LED light control, characterized in that: The invention comprises an LED light source, an incident polarizer, a liquid crystal glass body, an imaging polarizer, a Fresnel lens and a projection lens which are arranged in sequence; at least one photoelectric sensor is fixedly arranged on the side of the Fresnel lens or the projection lens, and the photoelectric sensor senses radial escape light emitted by the Fresnel lens or the projection lens in real time and outputs an electrical signal, and the power of the LED light source is adjusted by the strength of the electrical signal output by the photoelectric sensor.

2. A projection optical component based on LED light control, characterized in that: It includes an LED light source, an incident polarizer, a liquid crystal glass body, an imaging polarizer, a Fresnel lens and a projection lens which are arranged in sequence; It also includes a glass sheet, which is arranged between the imaging polarizer and the Fresnel lens, or between the Fresnel lens and the projection lens; at least one photoelectric sensor is fixedly arranged on the side of the glass sheet, and the photoelectric sensor senses the radial escape light emitted by the glass sheet in real time and outputs an electrical signal, and the power of the LED light source is adjusted by the strength of the electrical signal output by the photoelectric sensor.

3. A projection optical component based on LED light control according to claim 1 or 2, characterized in that: The LED light source, the incident polarizer, the liquid crystal glass body, the imaging polarizer, and the Fresnel lens are sequentially arranged in a screen chamber, and the screen chamber is a hollow sealed cavity.

4. The projection optical component based on LED light control according to claim 3, characterized in that: A screen room temperature sensor is arranged in the screen room, and the screen room temperature sensor detects the temperature in the screen room in real time.

5. The projection optical component based on LED light control according to claim 1 or 2, characterized in that: The incident polarizer is made of a polymer resin material that only allows light waves with a single vibration direction to pass through.

6. The projection optical component based on LED light control according to claim 5, characterized in that: The imaging polarizer is also made of a polymer resin material, which only allows light waves perpendicular to the polarization direction of the incident polarizer to pass through.

7. A projection device based on LED light control, characterized in that: It comprises the projection optical component, light control board, power supply and LED driving board and main control board as described in claim 1 or 2; the main control board is electrically connected to the liquid crystal glass body, the light control board, the power supply and LED driving board respectively; the light control board is electrically connected to at least one of the photoelectric sensors and the screen room temperature sensor respectively; the power supply and LED driving board is electrically connected to the LED light source.

8. The projection device based on LED light control according to claim 7, characterized in that: The light control panel includes a signal amplification circuit, a hysteresis circuit, a temperature detection output circuit, a dark scene power setting circuit and a voltage control circuit; the photoelectric sensor is electrically connected to the signal amplification circuit and the hysteresis circuit in sequence; the screen room temperature sensor is electrically connected to the temperature detection output circuit; the hysteresis circuit, the temperature detection output circuit and the dark scene power setting circuit are electrically connected to the voltage control circuit respectively.

9. The LED-based light control projection device according to claim 8, characterized in that: The voltage control circuit synthesizes the voltage signal output by the photoelectric sensor and processed by the signal amplification circuit, the hysteresis circuit, the voltage signal set by the dark scene power setting circuit, and the power limit voltage signal generated by the temperature detection output circuit, and generates a voltage signal for pulse width modulation of the subsequent PWM and transmits it to the main control board. The main control board generates a PWM signal with a corresponding duty cycle according to the current state of the image, and then controls the output power of the LED light source through the power supply and LED driving board.

10. The projection device based on LED light control according to claim 9, characterized in that: The PWM signal includes a duty cycle signal that changes with the brightness of the image, and also includes a minimum set power when the image is dark and a LED light source power limiting signal when the temperature in the screen room exceeds an upper limit.

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