Projection optical module and projection equipment

Abstract

The invention relates to a projection optical module and projection equipment, and aims to improve the color uniformity of the projection optical module and further improve the display effect of the projection equipment. The projection optical module comprises an LED light source; the light cone comprises a light inlet surface, a light outlet surface opposite to the light inlet surface and a side surface connected with the light inlet surface and the light outlet surface, and the LED light source is arranged on the light inlet surface; the light-emitting surface is arranged on the substrate, the light-filtering film is arranged on the light-emitting surface, the orthographic projection of the light-filtering film on the light-emitting surface coincides with the light-emitting surface, and the light-filtering film comprises a first central area and a first edge area surrounding the first central area; the blue light transmittance of the first central area is smaller than that of the first edge area; and / or the green light transmittance of the first central area is greater than that of the first edge area.

Description

Technical Field

[0001] The present invention relates to the field of projection technology, and in particular to a projection optical module and a projection device. Background Art

[0002] A single-chip LCD projection device is a projection product that uses a transmissive LCD panel to modulate the light emitted by an optical module to form an image, and then uses a projection lens to magnify the image and project it onto the projection area. Compared to projection devices based on other principles, such as DLP (Digital Light Processing) or LCoS (Liquid Crystal On Silion), single-chip LCD projection devices are inexpensive and easy to make.

[0003] An optical module in the related art uses a light cone to diffuse the light emitted by a light source. However, as the position of the light point and the light angle are different, the optical path of the light in the light cone is also different. The absorption coefficient of the medium for different wavelengths is different. Therefore, the color coordinates of the same spectrum will be different after passing through different optical paths, that is, the color is uneven. This is not conducive to improving the color uniformity of the optical module, and further not conducive to improving the display effect of the projection device. Summary of the invention

[0004] Based on this, the present application proposes a projection optical module and a projection device, so as to improve the color uniformity of the projection optical module, and further improve the display effect of the projection device.

[0005] An embodiment of the first aspect of the present application proposes a projection optical module, comprising: an LED light source; a light cone, the light cone comprising a light incident surface, a light exit surface opposite to the light incident surface, and a side surface connecting the light incident surface and the light exit surface, the LED light source being arranged on the light incident surface; and a light filter film, the light filter film being arranged on the light exit surface, the orthographic projection of the light filter film on the light exit surface coincident with the light exit surface, the light filter film comprising a first central area and a first edge area surrounding the first central area; the blue light transmittance of the first central area is less than the blue light transmittance of the first edge area; and / or the green light transmittance of the first central area is greater than the green light transmittance of the first edge area.

[0006] In some embodiments, the first edge region has a first transmittance function T1 (λ), and the first central region has a second transmittance function T2 (λ); the light exit surface includes a second central region and a second edge region surrounding the second central region, the second central region coincides with the first central region, the second edge region coincides with the first edge region, the second edge region has a first spectral function I1 (λ), and the second central region has a second spectral function I2 (λ);

[0007] Among them, T1(λ)I1(λ)=T2(λ)I2(λ), λ is the wavelength of visible light.

[0008] In some embodiments, the LED light source includes a plurality of LED chips, and the first spectral function I1(λ) satisfies the following formula:

[0009] ;

[0010] The second spectral function I2(λ) satisfies the following formula:

[0011] ;

[0012] in, is the spectrum of the LED chip, is the reflectivity function of the light cone, θ1 is the angle value of the angle formed by the light emitted from the light incident surface and the edge of the light emitting surface without reflection, θ2 is the angle value obtained by subtracting θ1 from the angle formed by the light emitted from the light incident surface and the edge of the light emitting surface after one reflection, θ3 is the angle value obtained by subtracting θ1 from 90° and then subtracting θ2, and the first direction is the direction from the light incident surface to the light emitting surface.

[0013] In some embodiments, the orthographic projection of the light cone on the first virtual plane is an isosceles trapezoid, the first virtual plane is perpendicular to the light incident surface, the isosceles trapezoid includes a first side and a second side arranged in parallel and a hypotenuse connecting the first side and the second side, the first side is the orthographic projection of the light incident surface on the first virtual plane, the second side is the orthographic projection of the light emitting surface on the first virtual plane, and the hypotenuse is the orthographic projection of the side surface on the first virtual plane;

[0014] The length of the first side is a, the angle between the hypotenuse and the extension line of the first direction is θ, the first direction is the direction from the light incident surface to the light exit surface, and the length of the hypotenuse b satisfies the following formula:

[0015] .

[0016] In some embodiments, the width Z of the first edge region satisfies the following formula:

[0017] .

[0018] In some embodiments, the difference between the blue light transmittance of the first central region and the blue light transmittance of the first edge region is between 10% and 20%.

[0019] In some embodiments, a difference between a green light transmittance of the first central region and a green light transmittance of the first edge region is between 10% and 20%.

[0020] In some embodiments, the shape of the light emitting surface and the light incident surface is one of a square and a rectangle.

[0021] In some embodiments, the projection optical module further includes an LCD panel disposed on a side of the filter film away from the LED light source; and / or, the projection optical module further includes a collimating lens disposed between the LCD panel and the filter film.

[0022] In some embodiments, the reflective surface of the light cone is provided with a metal oxide film layer and / or a metal film layer.

[0023] An embodiment of a second aspect of the present application provides a projection device, comprising the projection optical module of the first aspect.

[0024] In the present application, the filter film includes a first central area and a first edge area surrounding the first central area, and the blue light transmittance of the first central area is less than the blue light transmittance of the first edge area and / or the green light transmittance of the first central area is greater than the green light transmittance of the first edge area. In this way, first, the intensity of the green light in the edge area of ​​the light-emitting surface is reduced after filtering by the first edge area of ​​the filter film, and the intensity of the green light in the central area is increased after filtering by the first central area of ​​the filter film, so that the green light intensity in the final image display is uniform. Second, the intensity of the blue light in the edge area of ​​the light-emitting surface is increased after filtering by the first edge area of ​​the filter film, and the intensity of the blue light in the central area is reduced after filtering by the first central area of ​​the filter film, so that the blue light intensity in the final image display is uniform. In this way, it is beneficial to improve the color uniformity of the projection optical module, and then it is beneficial to improve the display effect of the projection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic structural diagram of a light cone optical module in the related art;

[0026] FIG2 is a schematic diagram of a light path of light propagating in a light cone in the related art;

[0027] Figure 3 This is a schematic diagram of the structure of a projection optical module according to an embodiment of the present application;

[0028] Figure 4 A schematic diagram showing a comparison between a first spectral function and a second spectral function according to an embodiment of the present application;

[0029] Figure 5 This is a schematic diagram of the orthographic projection structure of the light cone and the filter film of an embodiment of the present application on the first virtual plane;

[0030] Figure 6 It is a schematic diagram of another orthographic projection structure of the light cone and the filter film of the embodiment of the present application on the first virtual plane.

[0031] The reference numerals are as follows:

[0032] 1-light cone optical module; 2-light source; 3-light cone; 31-light incident surface; 32-upper surface; 33-lower surface; 34-optical axis; 4-collimating lens; 5-LCD panel; G-light emitting point;

[0033] 100-projection optical module; 110-LED light source; 120-light cone; 121-light incident surface; 1211-first edge; 122-light exit surface; 1221-second edge; 123-side; 1231-hypotenuse; 130-filter film; 140-LCD panel; S1-first virtual plane; A1-first central area; A2-second central area; B1-first edge area; B2-second edge area. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0035] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0039] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0040] FIG1 is a schematic diagram of the structure of a light cone optical module in the related art, and FIG2 is a schematic diagram of the optical path of light propagating in the light cone. As shown in FIG1, the light cone optical module 1 includes a light source 2 and a light cone 3, a collimating lens 4 and an LCD panel 5 sequentially arranged on the light output side of the light source 2. The light source 2 is arranged on the light incident surface 31 of the light cone 3. Assuming that the light incident surface of the light cone 3 has a light-emitting point G. As shown in FIG2, the positive projection figure of the light cone 3 on a certain plane is an isosceles trapezoid. Combining FIG1 and FIG2, it can be seen that the reflection of the light emitted from point A on the upper surface 32 and the lower surface 33 in the light cone 3 can be simplified as the reflection of the light emitted from point A on the two waist lines of the isosceles trapezoid. Considering the light energy loss caused by multiple reflections, in the general light cone scheme, the light is reflected at most twice. Then, the light emitted from point G can be divided into three angle intervals according to the number of reflections. As shown in FIG2, the first angle interval is, and the angle range with the optical axis 34 is 0 to θ1. The light in this angle interval does not pass through the reflection surface of the light cone 3 and is directly emitted. The second angle interval is that the angle range with the optical axis 31 is θ1 to θ2, and the light in this angle interval is emitted after a single reflection of the light cone 3. The third angle interval is that the angle range with the optical axis 34 is θ2 to 90°, and the light in this angle interval is emitted after a double reflection of the light cone 3. As can be seen from FIG. 2, according to the symmetry relationship, the light received on the LCD panel 5 is composed of the light emitted in 2 first angle intervals, 2 second angle intervals, and 2 third angle intervals. Among them, the light emitted in the first angle interval and the second angle interval fills the entire LCD panel 5, while the light emitted in the third angle interval is only distributed at the edge of the screen.

[0041] Thus, due to the secondary reflected light emitted in the third angle interval, the colors of the center and edge of the final picture are uneven, affecting the display effect of the image.

[0042] Based on the above problems, the present application proposes a projection optical module and a projection device, so as to improve the color uniformity of the projection optical module and further improve the display effect of the projection device.

[0043] The embodiment of the first aspect of the present application provides a projection optical module 100. Figure 3As shown, the projection optical module 100 includes an LED light source 110, a light cone 120 and a filter film 130. The light cone 120 includes a light incident surface 121, a light exit surface 122 opposite to the light incident surface 121, and a side surface 123 connecting the light incident surface 121 and the light exit surface 122. The LED light source 110 is disposed on the light incident surface 121. The filter film 130 is disposed on the light exit surface 122, and the orthographic projection of the filter film 130 on the light exit surface 122 coincides with the light exit surface 122. The filter film 130 includes a first central area A1 and a first edge area B1 surrounding the first central area A1. The blue light transmittance of the first central area A1 is less than the blue light transmittance of the first edge area B1, and / or, the green light transmittance of the first central area A1 is greater than the green light transmittance of the first edge area B1. To achieve color uniformity, at least one of the following conditions is satisfied: the blue light transmittance of the first central region is less than the blue light transmittance of the first edge region; and the green light transmittance of the first central region is greater than the green light transmittance of the first edge region.

[0044] In the present application, the projection optical module 100 includes an LED light source 110, a light cone 120, and a filter film 130. The LED light source 110 is used to provide the projection device with light required to form a projection image. The LED light source 110 emits white illumination light, wherein the LED light source 110 can be a white light source for laser-excited fluorescence. Alternatively, the LED light source 110 can be a monochromatic light source or a combination of light sources of different colors, the monochromatic light source can be any one of red, green, and blue, and the combination of light sources of different colors can be a combination of any one of red, green, and blue. This application does not limit this.

[0045] The light cone 120 refers to an optical device for homogenizing light. In addition, due to the high light collection efficiency of the light cone 120, the brightness of the projection optical module 100 can be improved and its power consumption can be reduced. Optionally, the light cone 120 can be a solid light cone, such as a solid glass cone rod made of glass; or, the light cone 120 can also be a hollow light cone, which is formed by connecting and enclosing a plurality of reflective surfaces in sequence. The light cone 120 has a light incident surface 121 and a light emitting surface 122 that are arranged opposite to each other. The cross-sectional area of ​​the light cone 120 gradually increases along the direction from the light incident surface 121 to the light emitting surface 122, so that the area of ​​the light emitting surface 122 of the light cone 120 is larger than the area of ​​the light incident surface 121. The light source 110 is arranged on the light incident surface 121. In this way, the light emitted by the light source 110 is homogenized by using the light cone 120, thereby forming a divergent surface light. In this way, it is beneficial to improve the uniformity and luminous area of ​​the light.

[0046] As the background technology, as shown in FIG. 1 and FIG. 2, the light received on the LCD panel is composed of light emitted in two first angle intervals, two second angle intervals, and two third angle intervals. Among them, the light emitted in the first angle interval and the second angle interval fills the entire LCD panel, while the light emitted in the third angle interval is only distributed at the edge of the screen. In this way, the spectral distribution at the edge of the light emitting surface 122 of the light cone 120 is different from the spectral distribution at the center of the light emitting surface 122, which ultimately causes uneven display of the screen.

[0047] Therefore, the projection optical module 100 of the present application further includes a filter film 130, which is disposed on the light exiting surface 122 of the light cone 120. The filter film 130 can filter light of different wavelengths, so that the spectrum of the light passing through the filter film 130 is controllable. After in-depth research, the inventors found that the main reason for the uneven display of the picture is that after the light emitted by the LED light source 110 is diffused by the light cone 120, the green light intensity in the light at the edge area of ​​the light exiting surface 122 of the light cone 120 is higher than the green light intensity in the light at the center area, while the blue light intensity in the light at the edge area of ​​the light exiting surface 122 is lower than the blue light intensity in the light at the center area.

[0048] In the present application, the filter film 130 includes a first central area A1 and a first edge area B1 surrounding the first central area A1. The blue light transmittance of the first central area A1 is less than the blue light transmittance of the first edge area B1, and the green light transmittance of the first central area A1 is greater than the green light transmittance of the first edge area B1. In this way, first, the intensity of the green light in the edge area of ​​the light exiting surface 122 is reduced after being filtered by the first edge area B1 of the filter film 130, and the intensity of the green light in the central area is increased after being filtered by the first central area A1 of the filter film 130, so that the green light intensity in the final image display is uniform. Second, the intensity of the blue light in the edge area of ​​the light exiting surface 122 is increased after being filtered by the first edge area B1 of the filter film 130, and the intensity of the blue light in the central area is reduced after being filtered by the first central area A1 of the filter film 130, so that the blue light intensity in the final image display is uniform. In this way, it is beneficial to improve the color uniformity of the projection optical module 100, and then it is beneficial to improve the display effect of the projection device.

[0049] In some embodiments, Figure 3As shown, the first edge area B1 has a first transmittance function T1 (λ), the first central area A1 has a second transmittance function T2 (λ), the light exit surface 122 includes a second central area A2 and a second edge area B2 surrounding the second central area A2, the second central area A2 coincides with the first central area A1, the second edge area B2 coincides with the first edge area B1, the second edge area B2 has a first spectral function I1 (λ), the second central area A2 has a second spectral function I2 (λ), T1 (λ) I1 (λ) = T2 (λ) I2 (λ), λ is the wavelength of visible light.

[0050] This embodiment proposes a method of setting different transmittances of the first central area A1 and the first edge area B1 of the filter film 130. Specifically, the first edge area B1 has a first transmittance function T1 (λ), and the first central area A1 has a second transmittance function T2 (λ). The first transmittance function T1 (λ) means that the transmittance of the first edge area B1 is related to the wavelength λ of visible light, and each wavelength of light in the first edge area B1 has a corresponding transmittance. The second transmittance function T2 (λ) means that the transmittance of the first central area A1 is related to the wavelength λ of visible light, and each wavelength of light in the first central area A1 has a corresponding transmittance. Further, the light exit surface 122 of the light cone 120 includes a second central area A2 and a second edge area B2, and the second central area A2 coincides with the first central area A1, and the second edge area B2 coincides with the first edge area B1. That is, the dividing boundary between the first central area A1 and the first edge area B1 of the filter film 130 is the same as the dividing boundary between the second central area A2 and the second edge area B2 of the light exit surface 122.

[0051] Furthermore, the second edge region B2 has a first spectral function I1 (λ), and the second central region A2 has a second spectral function I2 (λ). The first spectral function I1 (λ) means that the light intensity of the second edge region B2 of the light exit surface 122 is related to the visible light wavelength λ, and each wavelength of light in the second edge region B2 has a corresponding light intensity. The second spectral function I2 (λ) means that the light intensity of the second central region A2 of the light exit surface 122 is related to the visible light wavelength λ, and each wavelength of light in the second central region A2 has a corresponding light intensity.

[0052] Furthermore, the present embodiment defines T1(λ)I1(λ)=T2(λ)I2(λ). This formula indicates that the spectrum of the light emitted from the second edge area B2 after being filtered by the first edge area B1 of the filter film 130 is the same as the spectrum of the light emitted from the second center area A2 after being filtered by the first center area A1 of the filter film 130. That is, after the light passes through the filter film 130, the spectrum at the edge of the picture is the same as the spectrum at the center of the picture, which is beneficial to improve the color uniformity of the projection optical module 100.

[0053] It should be noted that, in the above formula, the first transmittance function T1 (λ) and the second transmittance function T2 (λ) of the filter film 130 are specifically set according to the obtained functional relationship between I1 (λ) and I2 (λ). It is easy to understand that when setting the first transmittance function T1 (λ) and the second transmittance function T2 (λ), the range of visible light wavelengths with a large light intensity difference in the first spectral function I1 (λ) and the second spectral function I2 (λ) can be selected, and then the transmittance size in the same wavelength range in the first transmittance function T1 (λ) and the second transmittance function T2 (λ) can be set according to the determined visible light wavelength and the corresponding light intensity. In other words, after obtaining the functional relationship between the first spectral function I1 (λ) and the second spectral function I2 (λ), when comparing the first spectral function I1 (λ) and the second spectral function I2 (λ), the wavelength range of visible light with a large light intensity difference can be compared.

[0054] like Figure 4 As shown, it is a schematic diagram of the normalized spectrum comparison of the first spectral function I1 (λ) and the second spectral function I2 (λ) of the embodiment of the present application. The inventors have found that in the first spectral function I1 (λ) and the second spectral function I2 (λ), when the wavelength is in the range of 500nm-600nm, the difference in light intensity between the two is large. That is, the yellow-green light intensity of the second edge area B2 of the light-emitting surface 122 is 10%-20% higher than the yellow-green light intensity of the second center area A2. Therefore, when setting the first transmittance function T1 (λ) and the second transmittance function T2 (λ), the present application only needs to adjust the transmittance of blue light and green light in the first transmittance function T1 (λ) and the second transmittance function T2 (λ), so as to achieve the effect of adjusting the uniformity of the picture.

[0055] In a specific embodiment, the difference between the blue light transmittance of the first central area A1 and the blue light transmittance of the first edge area B1 is between 10% and 20%, and the difference between the green light transmittance of the first central area A1 and the green light transmittance of the first edge area B1 is between 10% and 20%. In this way, it is beneficial to improve the color uniformity of the image of the projection optical module 100, and further to improve the display effect of the projection device.

[0056] In some embodiments, Figure 3 and Figure 5 As shown, the LED light source 110 includes a plurality of LED chips, and the first spectral function I1(λ) satisfies the following formula:

[0057] ;

[0058] The second spectral function I2(λ) satisfies the following formula:

[0059] ;

[0060] in, is the spectrum of the LED chip, is the reflectivity function of the light cone 120, θ1 is the angle value of the angle formed by the light L1 emitted from the light incident surface 121 and the first direction X when it is incident on the edge of the light emitting surface 122 without reflection, θ2 is the angle value obtained by subtracting θ1 from the angle formed by the light L1 emitted from the light incident surface 121 and the first direction when it is reflected once and incident on the edge of the light emitting surface 122, and θ3 is the angle value obtained by subtracting θ1 from 90° and then subtracting θ2.

[0061] This embodiment proposes a formula for obtaining the first spectral function I1 (λ) and the second spectral function I2 (λ). The LED chip can be regarded as a Lambertian light source, and its energy distribution conforms to I = cosθ. Figure 4 As shown, It refers to the spectrum of the light L1 emitted from the light incident surface 121 that directly hits the second edge region B2 of the light emitting surface 122 without being reflected, It refers to the spectrum of the light L2 emitted from the light incident surface 121 and hitting the edge of the light emitting surface 122 after one reflection, where It refers to the spectrum of the light L3 emitted from the light incident surface 121 and hitting the other side edge of the light emitting surface 122 after one reflection.

[0062] and It refers to the spectrum of the light L4 emitted from the light incident surface 121 and hitting the second edge area B2 of the light emitting surface 122 after secondary reflection. It refers to the spectrum of the light emitted from the light incident surface 121 directly irradiating to the second central area A1 of the light emitting surface 122, It refers to the spectrum of the light emitted from the light incident surface 121 and hitting the second central area A1 of the light emitting surface 122 after one reflection. It means that the reflectivity of the light cone 120 is related to the wavelength of visible light. function.

[0063] It should be noted that in the above formula, The reflectivity of the reflection surface of the light cone 120 can be measured by a reflectivity meter to obtain the reflectivity. It can be obtained by measuring the light of the LED chip with a spectrum measuring instrument. θ1, θ2 and θ3 can be obtained through geometric relationships. In this way, the first spectrum function I1 (λ) and the second spectrum function I2 (λ) can be obtained through the above formula.

[0064] The specific calculation process of θ1, θ2 and θ3 is described below.

[0065] Specifically, Figure 3 and Figure 5 As shown, the orthographic projection of the light cone 120 on the first virtual plane S1 is an isosceles trapezoid ABEF. The first virtual plane S1 is perpendicular to the light incident surface 121. The isosceles trapezoid ABEF includes a first side 1211 and a second side 1221 arranged in parallel and a hypotenuse 1231 connecting the first side 1211 and the second side 1221. The first side 1211 is the orthographic projection of the light incident surface 121 on the first virtual plane S1, the second side 1221 is the orthographic projection of the light emitting surface 122 on the first virtual plane S1, and the hypotenuse 1231 is the orthographic projection of the side surface 123 and the filter film 130 on the first virtual plane S1. The length of the first side 1211 is a, the angle between the hypotenuse 1231 and the extension line of the first direction X is θ, and the length of the hypotenuse 1231 is b. The line connecting the midpoint of AB and the midpoint of EF is OP, and OP is parallel to the first direction X. The intersection point of the light L3 and the hypotenuse 1231 is D.

[0066] According to the geometric relationship, we can get: .but: .but . At this point, θ1 is known.

[0067] In triangle AOD, according to the sine theorem: ; In triangle DEF, according to the law of sines: Since AD+DE=AE=b, the above formulas can be combined to obtain the value of θ3, which is known. , we can get the value of θ2. In this way, θ1, θ2 and θ3 can all be obtained.

[0068] It should be noted that in order to ensure that at least part of the light emitted from the incident surface 121 can be secondary reflected in the light cone 120, the length b of the hypotenuse needs to meet certain requirements. Figure 3 and Figure 6As shown, it is a propagation optical path diagram of the outgoing light ray L5 which is 0° to the first side 1211 in the isosceles trapezoid ABEF. According to the geometric relationship, when the outgoing light ray L5 is emitted after being reflected twice in the isosceles trapezoid ABEF, there must be an angle interval within which the outgoing light ray can be reflected twice in the isosceles trapezoid ABEF. At this time, the second reflection point of the outgoing light ray L5 on the hypotenuse 1231 is recorded as M. In addition, a line segment MN is made that passes through point M and is parallel to the line segment EF, and point N is the intersection of the line segment MN and the other hypotenuse 1231. At this time, the length of the line segment BM is the minimum value of the hypotenuse 1231. According to the geometric relationship, we have Then, the length b of the hypotenuse 1231 satisfies the formula: .

[0069] In some embodiments, Figure 6 As shown, the width Z of the first edge region B1 satisfies the following formula:

[0070] .

[0071] In this embodiment, the width Z of the first edge area B1 is defined by the above formula, thereby obtaining the boundary line between the first edge area B1 and the first central area A1. Specifically, the filter film 130 is arranged on the light exiting surface 123. The intersection point of the outgoing light L5 on the filter film 130 is K1. Due to the symmetry of the light cone 120, there is another intersection point K2 on the other side of OP. Then, the width of the first central area A1 of the filter film 130 is the length between K1 and K2, and the width Z of the first edge area B1 is the length between K1 and F, or the length between K2 and E.

[0072] In triangle MFK1, according to the geometric relationship and the law of reflection, we can get: , . Then from the sine theorem we can get: . Further, , . Then the width Z of the first edge area B1 is: Thus, the boundary line between the first edge area B1 and the first central area A1 can be obtained.

[0073] In some embodiments, the shape of the light-emitting surface 122 and the light-entering surface 121 is one of a square or a rectangle. This embodiment defines the shape of the light-emitting surface 122 and the light-entering surface 121 of the light cone 120. The shape of the light-emitting surface 122 and the light-entering surface 121 is set to be a square or a rectangle. On the one hand, the spot shape of the outgoing light diverging through the light cone 120 matches the shape of the display screen, which is conducive to improving the adaptability and versatility of the projection optical module 100. On the other hand, it is also conducive to improving the convenience of arranging the light source 110 on the light-entering surface 121.

[0074] In some embodiments, Figure 3 As shown, the projection optical module 100 also includes an LCD panel 140 disposed on the side of the light cone 120 away from the LED light source 110. The LCD panel 140 is a "liquid crystal display" and is used to convert the received illumination light into image light. It is usually composed of a polarizer, an array substrate, an opposing substrate, and a liquid crystal material sandwiched between the two. The technology of the LCD panel 140 is mature and the cost is low, which is conducive to reducing the production cost of the projection optical module 100.

[0075] In some embodiments, the projection optical module 100 further includes a collimating lens (not shown) disposed between the LCD panel 140 and the filter film 130. The collimating lens refers to a lens structure that collimates the light emitted from the light cone 120. By providing the collimating lens, on the one hand, the emitted light can be incident on the LCD panel 140 in parallel, reducing the probability of light being reflected on the LCD panel 140, thereby facilitating improving the utilization rate of light. On the other hand, the light cone 120 is combined with the collimating lens, so that the output light of the collimating lens presents a uniform light spot, which is also beneficial to further improve the uniformity of color on the LCD panel 140. Optionally, the collimating lens can be, for example, a Fresnel lens.

[0076] In some embodiments, a metal oxide film layer and / or a metal film layer is provided on the reflective surface of the light cone 120. The metal oxide film layer and / or the metal film layer can be plated on the reflective surface to form a metal oxide film layer and / or a metal film layer, so that the metal oxide film layer and / or the metal film layer on the reflective surface can realize the reflection effect of the reflective surface of the light cone 120. Since metals absorb short waves more strongly, the use of light cones, especially light cones with oxide layers, as lighting systems often results in a "rainbow degree" phenomenon, that is, the periphery of the picture is redder than the center of the picture, so the present application can be applied to light cones 120 with metal oxide film layers and / or metal film layers on the reflective surface.

[0077] The second embodiment of the present application provides a projection device, including the projection optical module 100 of the first aspect. The projection device of the present application uses the projection optical module 100 of the first aspect. In this way, the intensity of green light and blue light in the final image display is uniform, which is conducive to improving the color uniformity of the projection optical module 100, and further conducive to improving the display effect of the projection device.

[0078] 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 above-described 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.

[0079] 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 module, characterized in that: include: LED light source; A light cone, the light cone comprising a light incident surface, a light emitting surface opposite to the light incident surface, and a side surface connecting the light incident surface and the light emitting surface, the LED light source being arranged on the light incident surface; as well as A filter film, wherein the filter film is arranged on the light emitting surface, an orthographic projection of the filter film on the light emitting surface coincides with the light emitting surface, and the filter film comprises a first central area and a first edge area surrounding the first central area; The blue light transmittance of the first central region is lower than the blue light transmittance of the first edge region; and / or the green light transmittance of the first central region is higher than the green light transmittance of the first edge region.

2. The projection optical module according to claim 1, characterized in that: The first edge region has a first transmittance function T1 (λ), and the first central region has a second transmittance function T2 (λ); The light emitting surface includes a second central area and a second edge area surrounding the second central area, the second central area coincides with the first central area, the second edge area coincides with the first edge area, the second edge area has a first spectral function I1(λ), ​​and the second central area has a second spectral function I2(λ); Among them, T1(λ)I1(λ)=T2(λ)I2(λ), λ is the wavelength of visible light.

3. The projection optical module according to claim 2, characterized in that: The LED light source includes a plurality of LED chips, and the first spectral function I1(λ) satisfies the following formula: ； The second spectral function I2(λ) satisfies the following formula: ； in, is the spectrum of the LED chip, is the reflectivity function of the light cone, θ1 is the angle value of the angle formed by the first direction when the light emitted from the light incident surface is incident on the edge of the light emitting surface without reflection, θ2 is the angle value obtained by subtracting θ1 from the angle formed by the first direction when the light emitted from the light incident surface is reflected once and incident on the edge of the light emitting surface, θ3 is the angle value obtained by subtracting θ1 from 90° and then subtracting θ2, and the first direction is the direction from the light incident surface to the light emitting surface.

4. The projection optical module according to claim 1, characterized in that: The orthographic projection of the light cone on the first virtual plane is an isosceles trapezoid, the first virtual plane is perpendicular to the light incident surface, the isosceles trapezoid includes a first side and a second side arranged in parallel and a hypotenuse connecting the first side and the second side, the first side is the orthographic projection of the light incident surface on the first virtual plane, the second side is the orthographic projection of the light emitting surface on the first virtual plane, and the hypotenuse is the orthographic projection of the side surface on the first virtual plane; The length of the first side is a, the angle between the hypotenuse and the extension line of the first direction is θ, the first direction is the direction from the light incident surface to the light emitting surface, and the length b of the hypotenuse satisfies the following formula: 。 5. The projection optical module according to claim 4, characterized in that: The width Z of the first edge region satisfies the following formula: 。 6. The projection optical module according to claim 1, characterized in that: A difference between the blue light transmittance of the first central area and the blue light transmittance of the first edge area is between 10% and 20%; And / or, a difference between a green light transmittance of the first central area and a green light transmittance of the first edge area is between 10% and 20%.

7. The projection optical module according to claim 1, characterized in that: The light emitting surface and the light incident surface are in a shape of a square or a rectangle.

8. The projection optical module according to claim 1, characterized in that: The projection optical module further includes an LCD panel disposed on a side of the filter film away from the LED light source; and / or the projection optical module further includes a collimating lens disposed between the LCD panel and the filter film.

9. The projection optical module according to claim 1, characterized in that: A metal oxide film layer and / or a metal film layer is provided on the reflective surface of the light cone.

10. A projection device, characterized in that: Comprising the projection optical module as described in any one of claims 1-9.

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