CN203786454U - Lighting system and projection device - Google Patents

Abstract

An illumination system comprises a light source module and a refractive element group. The light source module provides a surface light source on an object plane, the refraction component group projects the surface light source on the object plane to an image plane, wherein the refraction component group has an aspheric surface, so that the root mean square radius of a central facula generated by one point on the surface light source at the intersection of the image plane and the optical axis of the refraction component group is larger than the average value of the root mean square radii of a plurality of edge facula generated by other points on the surface light source at the edge of the image plane, thereby providing the surface light source with central brightness larger than edge brightness in brightness distribution and further compensating the effect of larger degree of reduction of the edge brightness caused by a screen.

Description

Lighting system and projection device

technical field

The utility model relates to an optical system and a display device, in particular to an illumination system and a projection device.

Background technique

With the development of today's technology, large-size, high-resolution display devices are mostly a video wall (Video wall) formed by splicing a certain number of display devices. Since the splicing of multiple display devices requires consistency in color and brightness, the rear-projection system (Rear-projection system) has become the most suitable technical solution for video walls due to its consistency in light sources.

In order to improve the brightness and color uniformity seen by the observer, the transmissive screen of the rear projection system basically has a Fresnel lens (Fresnel lens) and a lenticular lens (Lenticular lens). The Fresnel lens will The divergent chief ray emitted by the projection lens is shaped into a direction perpendicular to the screen, and the lenticular lens receives the light from the Fennel lens and controls the opening angle of the light exiting the screen, which increases the viewing angle of the screen.

In terms of uniformity of screen brightness, the best uniformity is 100% ANSI (American National Standards Institute) uniform brightness distribution, that is, the brightness of the entire screen is exactly the same. However, when the light emitted by the rear projection system passes through the transmissive screen, the central brightness is better than the peripheral brightness in the brightness distribution. That is to say, since the incident angle of light increases around the transmissive screen, the amount of light passing through the transmissive screen is relatively reduced, so the peripheral brightness of the transmissive screen decreases. This phenomenon is more serious on short-focus projection systems, and therefore it is impossible to design a small-volume rear projection system with short-focus projection. There will also be additional electronic signal processing to improve this phenomenon and increase its production capacity. cost.

US Patent No. 5868481 discloses a rear projection display device, US Patent No. 4824225 discloses an illumination optical system, and US Patent No. 7023619 discloses a projection system.

Utility model content

The utility model provides an illumination system, which is suitable for providing a surface light source whose central luminance is greater than the edge luminance in luminance distribution, thereby compensating the effect of greater edge luminance loss caused by the screen.

The utility model provides a projection device, which is suitable for providing an image with uniform brightness.

An embodiment of the present invention provides a lighting system, including a light source module and a diopter group, the light source module provides a surface light source on an object plane, and the diopter group projects the surface light source on the object plane Image plane, wherein the dioptric element group has an aspheric surface, so that the root mean square radius of a central spot generated by a point on the surface light source at the intersection of the image plane and an optical axis of the dioptric element group is larger than other points on the surface light source The average value of the root-mean-square radii of multiple edge spots generated at the edge of the image plane.

An embodiment of the present invention provides a projection device, which includes a light valve, an illumination system, a projection lens and a penetrating screen. The lighting system includes a light source module and a diopter group. The light source module provides a surface light source on an object plane. The diopter group projects the surface light source on the object plane onto the active surface of the light valve. The diopter group It has an aspheric surface, so that the root mean square radius of a central light spot produced by a point on the surface light source at the intersection of the active surface and an optical axis of the refractive element group is greater than that produced by other points on the surface light source at the edge of the active surface The average of the root-mean-square radii of multiple edge flares. The light valve converts the surface light source into an image beam, the projection lens is arranged on the transmission path of the image beam, and the transmissive screen is arranged on the transmission path of the image beam from the projection lens.

In one embodiment of the present invention, the refractive element group includes a plurality of lenses arranged from the object plane to the image plane (active surface), and the lens closest to the image plane (active surface) faces the image plane (active surface) The surface is aspherical, or the surface of the lens closest to the object plane facing the object plane is aspheric.

In one embodiment of the present invention, the light source module includes a light emitting element and a light homogenizing element. The light emitting element is used to emit an illumination beam. the light-emitting side of the chemical element.

In an embodiment of the present invention, the geometric spot radius (Geometric spotradius) of the central spot is larger than the average value of the geometric spot radii of these edge spots.

In an embodiment of the present invention, the lighting system meets I ₁ /I ₀ >1.05, where I ₀ is the relative illuminance at the intersection of the image plane (active surface) and the optical axis of the refractive element group, and I ₁ is the image plane The relative illuminance of the (active surface) edge.

In an embodiment of the present invention, each of the central light spot and these edge light spots has a circular area, and the centers of these circular areas are respectively located at the central points of the central light spot and these edge light spots, and the circular areas of the central light spot have The light energy of the central spot accounts for α% of the total light energy of the central spot, and the light energy in the circular area of each edge spot in these edge spots accounts for α% of the total light energy of the edge spot, of which the circular area of the central spot is The radius is greater than the radius of the circular area of each edge spot, and 50≤α≤95.

In one embodiment of the present invention, the part of the aspheric surface close to the optical axis of the diopter group is a curved concave surface, and the part of the aspheric surface far away from the optical axis of the dioptric element group is a ring-shaped curved surface surrounding the curved concave surface. convex.

In one embodiment of the present invention, the part of the aspheric surface close to the optical axis of the refractive element group is a slightly convex surface, and the part of the aspheric surface far away from the optical axis of the refractive element group is a slightly convex surface. A convex curved convex surface. Among them, the offset (sag value) ratio of each point with an R value of 0.3 on the aspheric surface is less than 0.1, the offset ratio of each point with an R value of 0.5 on the aspheric surface is less than 0.2, and the sag value of each point on the aspheric surface with an R value of 0.7 The offset ratio of each point is less than 0.5, where the R value of a point on the aspheric surface is the ratio of the distance between the point and the optical axis and the maximum distance between the aspheric surface and the optical axis, and the offset ratio of the point is on the aspheric surface to the optical axis The ratio of the offset of the point in the direction to the maximum offset of the aspheric surface in the direction of the optical axis.

In one embodiment of the present invention, the aspherical surface conforms to the aspheric surface formula

$\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; cy</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; ,</span>$

Where Z is the offset in the direction of the optical axis of the aspheric surface, c is the reciprocal of the radius of the close spherical surface, K is the quadratic surface coefficient, y is the offset in the direction of the optical axis perpendicular to the aspheric surface, and A ₁ , A ₂ , A ₃ , A ₄ , A ₅ are aspherical coefficients, where -0.025<c<-0.005 and -500<K<-40, A ₁ , A 2 , A ₃ , _{A 4 ,} A ₅ At least one of them is opposite to the sign of c. The Z value corresponding to the position of y=0 of the aspheric surface is not the maximum value. The aspherical surface includes a position with a slope of 0. The position with a slope of 0 means that Z is relatively The position where the first derivative of y is 0, and the position where the slope is 0 falls at y=0.3γ to y=0.7γ, where γ is the maximum distance of the aspheric surface in the y direction relative to the optical axis (maximum radius ).

In an embodiment of the present invention, the dioptric element group includes at least one reflector, and the aspheric surface is a reflective surface of the reflector.

In an embodiment of the present invention, the transmissive screen includes a Fresnel lens surface and a cylindrical lens surface, the Fresnel lens surface is arranged on the transmission path of the image beam, and the cylindrical lens surface is arranged on the surface from the Fresnel lens. On the transmission path of the image beam on the surface, the surface of the lenticular lens has a plurality of lenticular microlens structures, each lenticular microlens structure extends along a first direction, and these lenticular microlens structures are arranged along a second direction.

In an embodiment of the present invention, the projection device further includes an internal total reflection prism, which is arranged on the light path between the refractive element group and the light valve, on the transmission path of the image beam, and is located between the light valve and the projection between shots.

Based on the above, the lighting system and the projection device in the embodiment of the present invention can make the surface light source provided by the light source module pass through the aspheric refractive element group in brightness by using the aspheric surface of the above-mentioned dioptric element group. The distribution has the characteristic that the brightness of the edge is greater than the brightness of the center, and then compensates the effect of a larger degree of loss of the edge brightness caused by the screen. In this way, when the image light beam passes through the transmissive screen, an image with uniform brightness can be produced.

Description of drawings

In order to make the above-mentioned features and advantages of the present utility model more obvious and understandable, the following specific embodiments are described in detail in conjunction with the accompanying drawings as follows:

Fig. 1A is a schematic diagram of an illumination system in an embodiment of the present invention.

Fig. 1B is a front view from the refractive element group to the image plane in the embodiment of the present invention.

Fig. 2 is a cross-sectional view of a lens with an aspheric surface in the first embodiment of the present invention.

FIG. 3A is a schematic diagram of the projection device in the first embodiment of the present invention.

FIG. 3B is a schematic diagram of a projection device in another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a lens with an aspheric surface in an embodiment of the present invention.

FIG. 5 is a relationship diagram of the surface offset of the aspheric surface in an embodiment of the present invention.

6 is a schematic diagram of relative illumination on the active surface of the light valve in the projection device in the first embodiment of the present invention.

Figure 7A is a front view of the active surface for the light valve in the first embodiment of the present invention.

FIG. 7B is a schematic diagram of light spots for each point on the active surface of the light valve in the first embodiment of the present invention.

FIG. 8 is a diagram of light energy distribution corresponding to each light spot on the active surface of the image plane or light valve in the first embodiment of the present invention.

Fig. 9 is a partial schematic diagram of a projection device in another embodiment of the present invention.

Fig. 10 is a partial schematic diagram of a projection device in another embodiment of the present invention.

Detailed ways

FIG. 1A is a schematic diagram of an illumination system in an embodiment of the present invention, and FIG. 1B is a front view from a diopter group to an image plane in an embodiment of the present invention. 1A and 1B, the lighting system 100 includes a light source module 110 and a diopter group 120, wherein the light source module 110 provides a surface light source (not shown) on the object plane 121, and the illumination beam L ₁ from the surface light source passes from the object plane 121 Entering the diopter group 120 , the diopter group 120 projects the surface light source on the object plane 121 onto the image plane 123 . Please refer to FIG. 1A and FIG. 1B. In this embodiment, the refractive element group 120 has an aspheric surface 122, which is disposed near the image plane 123 and facing the end of the image plane 123 and is suitable for being penetrated by the illumination beam _L1 , The aspheric surface 122 is suitable for allowing a point on the surface light source to at least form a central spot 130 located in the central area of the image plane 123 at the intersection of the image plane 123 and the optical axis B of the diopter group 120 and to allow other points of the surface light source to The edge area on the image plane 123 forms a plurality of edge light spots 132 (in this embodiment, FIG. 1B shows three edge light spots as a schematic), and the root mean square (Root Mean Square, RMS) radius of the central light spot 130 is larger than these edge light spots 132 Therefore, in the illumination system 100 of this embodiment, the brightness distribution of the light beam from the surface light source on the object plane 121 on the image plane 123 has the characteristic that the edge brightness is greater than the central brightness.

In more detail, the illumination system 100 of this embodiment provides an illumination beam L ₁ on the image plane 123 that produces a darker center and brighter edge in the brightness distribution, and this characteristic is suitable for applications such as On a transmissive projection screen, the above-mentioned characteristic that the edge brightness is greater than the central brightness allows the beam from the surface light source to pass through the optical element without affecting the uniformity of the penetration due to the difference in the incident angle of the beam. In other words, in this embodiment, after penetrating the image plane, the illuminating light beam L ₁ reaches a transmissive screen, for example, which has a plurality of optical microstructures distributed on the surface. When the light beam L ₁ is delivered to one side of the transmissive screen When , the surrounding area of the transmissive screen (that is, the edge area far away from the optical axis B) is likely to have a lower light penetration efficiency than the light penetration efficiency of the central area of the screen because of the large angle of the light beam incident on the screen, that is, On the other side of the screen, images with lower edge brightness will appear. Therefore, the light beams provided by the light source module in this embodiment have the characteristics of a darker center and brighter edges in brightness distribution, which can effectively improve the brightness displayed on the screen. Evenness.

Fig. 2 is a cross-sectional view of a lens with an aspheric surface in the first embodiment of the present invention. Please refer to Fig. 2, in the present embodiment, lens 220 is the optical element of one of them in the dioptric element group 120 of Fig. The part of the optical axis B shown in FIG. 1 ) is a curved concave surface, and the part of the aspheric surface 122 away from the optical axis B of the refractive element group 120 (as shown in FIG. 1 ) is a curved concave surface surrounding the above-mentioned The ring-shaped curved convex surface, that is, the aspherical surface 122 is a surface with a recurved property. In more detail, referring to FIG. 2, according to the present embodiment, according to the z direction d2 and the y direction d1, the aspheric surface 122 conforms to the formula

$\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; cy</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; ,</span>$

Where Z is the offset in the z direction d2, c is the reciprocal of the radius of the close sphere, K is the quadratic surface coefficient, y is the offset in the y direction d1, and A ₁ , A ₂ , A ₃ , A ₄ and A ₅ are aspherical coefficients, where -0.025<c<-0.005 and -500<K<-40, at least one of the aspheric coefficients A ₁ , A ₂ , A ₃ , A ₄ , and A ₅ One is opposite to the positive and negative sign of the reciprocal c of the radius of the close spherical surface. The z value corresponding to the position of y=0 of the aspheric surface is not the maximum value. The aspheric surface includes a position with a slope of 0, and the position with a slope of 0 refers to z The position where the first derivative relative to y is 0, and the position where the slope is 0 falls in the range of y=0.3γ to y=0.7γ, where the distance γ is the maximum distance of the aspheric surface in the y direction relative to the optical axis (maximum radius). In other words, please refer to FIG. 2 , in this embodiment, by changing the radius of curvature of the aspheric surface 122 of the lens 220 relative to the optical axis B, the light beam penetrating the surface of the aspheric surface 122 away from the optical axis B is relatively non-spherical. The beam of the surface of the spherical surface 122 close to the optical axis B is concentrated.

FIG. 3A is a schematic diagram of the projection device in the first embodiment of the present invention, and FIG. 3B is a schematic diagram of the projection device in another embodiment of the present invention. Please refer to FIG. 3A, the projection device 300 in the first embodiment of the present utility model has an illumination system, a light valve 310, an internal total reflection prism 330, a projection lens 320, and a transmissive screen 340. The illumination system includes a light source module 110 and The dioptric element group 120 , and the light source module 110 includes a light emitting element 112 and a light homogenizing element 114 . The dioptric element group 120 includes a lens 210A, a lens 210B, a lens 210D, a lens 210E, a mirror 210C, and a lens 220 with an aspheric surface 122 on its surface. In this embodiment, the lens 220 has the same cross-section as that in FIG. 2 , that is, the aspheric surface 122 of the lens 220 has the same curvature radius and attainable effects as the aspheric surface in FIG. 2 , but it is not limited thereto. In other embodiments, the aspheric surface 122 of the lens 220 may have other curvature radii on its curved concave surface and annular curved convex surface. In this embodiment, the light emitting element 112 is, for example, a light emitting diode (Light Emitting Diode, LED), but is not limited thereto. In other embodiments, the light emitting element 112 may be an organic light emitting diode (Organic Light Emitting Diode, OLED) and other components suitable for emitting light beams. In this embodiment, the light homogenizing element 114 is, for example, a solid or hollow light integrating cylinder, but it is not limited thereto. An optical element that emits a beam of light.

First of all, _for the _part of the lighting system in the first embodiment of the present utility model, in this embodiment, please refer to FIG. The light exit side 116 of the refraction element 114 is emitted to the dioptric element group 120 . In more detail, in this embodiment, the light homogenizing element 114 provides a surface light source on the light emitting side 116 , that is to say, the object plane of the lighting system in this embodiment is located at the light emitting side 116 of the light homogenizing element 114 . Please refer to FIG. 3A , the illuminating light beam L ₂ sequentially penetrates the lens 210A and the lens 210B of the dioptric element group 120 and is reflected by the mirror 210C, and the reflected light beam L ₂ then passes through the lens 210D, the lens 210E and the lens 220 in sequence. Reaching the total internal reflection prism 330 , the light beam L ₂ is reflected to the light valve 310 by the total internal reflection prism 330 . In other words, the dioptric element group 120 of this embodiment projects the light beam _L2 from the light exit side 116 (that is, the object plane of this embodiment) to an active surface 223 of the light valve 310, the active surface 223 can be rectangular, and Here the active surface 223 of the light valve 310 is located at the image plane of the dioptric element set 120 . That is to say, in this embodiment, because the light beam L ₂ has the aspheric surface 122 that penetrates the lens 220, when it reaches the active surface 223 (that is, the image plane of this embodiment), the illumination light beam L ₂ has an edge in the brightness distribution The characteristic that the brightness is greater than the central brightness.

Next, in the first embodiment of the present utility model, the illuminating light beam L ₂ hits the active surface 223 of the light valve 310 and is reflected as an image light beam L ₃ , and the image light beam L ₃ sequentially penetrates the internal total reflection prism 330 and projects lens 320 and reaches the transmissive screen 340, because the light beam _L2 has the characteristic that the edge brightness is greater than the central brightness in the brightness distribution, so the image beam _L3 after being reflected by the active surface 223 of the light valve 310 will also be at the brightness The distribution has the characteristic that the corresponding edge brightness is greater than the central brightness. In this embodiment, the lens 220 is the lens closest to the internal total reflection prism 330 in the diopter group 120, and the aspheric surface 122 of the lens 220 is arranged on the side close to the internal total reflection prism 330 and faces the internal total reflection prism 330, but the configuration of the above-mentioned aspheric surface in the refractive element group 120 is not limited thereto. Please refer to FIG. 3B , in other embodiments, the lens 220 is the lens closest to the light homogenizing element 114 in the refractive element group 120, and the aspheric surface 122 of the lens 220 can also be arranged at one end close to the light homogenizing element 114 and Facing the light homogenizing element 114 . 3A and 3B, the transmissive screen 340 has a Fresnel lens (Fresnel Lens) surface 342 and a lenticular lens (Lenticular lens) surface 344, and the Fresnel lens surface 342 is suitable for allowing the projection lens 320 to project The light beam is focused and collimated, and the cylindrical lens surface 344 has, for example, a plurality of cylindrical microlens structures 346 parallel to each other, and these cylindrical microlens structures 346 are arranged along the second direction _d3 , and each cylindrical microlens structure 346 is arranged along the vertical direction d3. The first direction extends in the second direction _d3 (referring to what is shown in FIG. 3A and FIG. 3B , the first direction is, for example, a direction perpendicular to the paper surface or a vertical direction to the paper surface). Specifically, referring to FIG. 3A , in this embodiment, the image light beam L ₃ includes, for example, the light beam L ₄ and the light beam L _5. After arriving at the transmissive screen 340, the image light beam L 3 penetrates the Fresnel lens surface 342 and the lenticular lens surface 344 in sequence, While the Fresnel lens surface 342 is suitable for focusing and collimating the light beam _L4 and the light beam _L5 , the cylindrical lens surface 344 is suitable for diverging the light beam _L4 and the light beam _L5 , wherein, for example, the light beam _L4 is close to the transmissive screen The incident angle of the light beam on the Fresnel lens surface 342 in the edge region of 340 is larger than the light beam incident angle near the central region of the transmissive screen 340 such as the light beam _L5 , so the light penetration efficiency of the edge region of the transmissive screen 340 is relatively large. The light penetration efficiency in the central area of the transmissive screen 340 will be relatively low, and in combination with the above-mentioned image beam L3, the brightness distribution of the image beam _L3 has the characteristic that the edge brightness is greater than the central brightness. Therefore, the image beam _L3 penetrates through the penetrating After the transmissive screen 340, it will still be compensated by the transmissive screen 340 to form an image with uniform brightness.

FIG. 4 is a cross-sectional view of a lens with an aspheric surface in an embodiment of the present invention. Please refer to FIG. 4 , in this embodiment, the lens 222 has an aspheric surface 124, and the aspheric surface 124 is a slightly convex surface near the optical axis B of the refractive element group 120 (please refer to FIG. 1 ), And the part of the aspheric surface 124 away from the optical axis B of the dioptric element group 120 (please refer to FIG. 1 ) is an annular curved convex surface surrounding a slightly convex surface. In detail, FIG. 5 is a relationship diagram of the surface offset of the aspheric surface in an embodiment of the present invention. Please refer to FIGS. The distance between B is divided by the value of the distance γ, wherein the value of the distance γ is the maximum distance (maximum radius) between the aspheric surface 124 and the optical axis B; and the vertical axis of Fig. 5 is a point on the aspheric surface 124 of Fig. 4 The offset value (sag value) in the direction of the optical axis B, which is the axial distance between a point on the aspheric surface 124 and the straight line E divided by the distance h, where h is the maximum distance between a point on the aspheric surface 124 and the straight line E Axial distance, and the line E is perpendicular to the optical axis B. In more detail, the aspheric surface 124 in this embodiment has an offset value (sag value) less than 0.1 at the position of R=0.3, and its offset value (sag value) is less than 0.2 at the position of R=0.5. =0.7, its offset value is less than 0.5.

With the characteristics of the curvature of the above-mentioned lens 222, the utility model can be configured similarly to FIG. 3A and FIG. 3B in other embodiments, but the difference is that the lens 122 is replaced by the lens 222. The spherical surface 124 also faces the TIR prism 330 , while the lens 222 is configured in FIG. 3B , and the aspheric surface 124 also faces the light homogenizing element 114 . In more detail, referring to Fig. 2 and Fig. 4 together, the surface curvature characteristics of the aspheric surface 122 and the aspheric surface 124 in the embodiment of the present utility model all have the ability to make the light beam penetrate the place close to the optical axis, and have a lower The optical energy density of the beam penetrates far away from the optical axis, and has a higher optical energy density. Further, with reference to FIG. 3A , the projection device 300 in the embodiment of the present utility model has the above-mentioned aspheric surface, such as the aspheric surface 122 or the aspheric surface 124, so that the amount of the light beam L ₄ can be relatively increased, for example, the light beam The amount of L ₅ is relatively reduced, so that the screen that originally exhibits uneven brightness due to the refraction and reflection of the light beam in the screen and the angle of the light beam incident on the screen can present a picture with uniform brightness. Furthermore, the projection device 300 of this embodiment is, for example, a rear projection display.

Next, the functions that can be achieved by the lighting system and the projection device in the embodiment of the present invention will be described in detail with reference to the drawings. FIG. 6 is a schematic diagram of the relative illumination on the active surface of the light valve in the projection device in the first embodiment of the present invention. Please refer to FIG. 3A and FIG. 6 . The lens 220 of 122 or the lens 222 with the aspheric surface 124 can make the relative illuminance of the light beam _L2 on the active surface 223 in the projection device have, for example, the distribution relationship shown in FIG. The offset of the reference point from the optical axis of beam _L2 . In more detail, in the first embodiment of the present utility model, the refractive element group 120 can make the relative illuminance of the surface light source emitted by the light source module 110 in the edge area of the image plane (active surface 223 ) be greater than that in the central area. Illumination, and the relative illuminance of the edge area divided by the relative illuminance of the central area is greater than 1.05.

7A is a front view of the active surface 223 of the light valve in the first embodiment of the present invention, and FIG. 7B is a schematic diagram of light spots on the active surface 223 of the light valve in the first embodiment of the present invention. Please refer to FIG. 7A and FIG. 7B together. In this embodiment, the spot pattern in FIG. 7B has the distribution diagrams of light beams with wavelengths of 460nm, 540nm and 620nm, and the edge spot distribution diagrams 501-508 correspond to the light beams in FIG. 7A respectively. The edge light fields 401 - 408 in the edge area on the active surface 223 of the valve, and the central light spot distribution diagram 509 correspond to the central light field 409 in the central area on the active surface 223 of the light valve in FIG. 7A . 7A and 7B, it can be seen that in the first embodiment of the present invention, the root mean square radius (RMS radius) of the central light field 409 is greater than the average value of the root mean square radii of the edge light fields 401-408, and in the first embodiment The geometric spot radius (Geometric spot radius) of the central light field 409 is greater than the average value of the geometric spot radii of the edge light fields 401-408.

The projection device of the first embodiment of the present utility model illustrates the light uniformity of the position (plane) after the light beam penetrates the penetrating screen according to the light uniformity stipulated by the American National Standards Institute (ANSI). , where when the projection device has the above-mentioned aspheric surface but no transmissive screen, the corresponding light uniformity results are shown in the table below.

In addition, when there is only a transmissive screen but no aspheric surface, the measurement is as follows

Finally, in the case of an aspheric projection device and a penetrating screen, the following table is measured

Here, the center point of each area when there is no transmissive screen in this embodiment or the imaging surface formed by the light beam passing through the transmissive screen is equally divided into nine areas by a nine-square grid is used as the measurement brightness The reference point, plus the four points whose distance from the four corners to the center point of the imaging plane is one-tenth of the distance as the reference point for measuring the brightness, a total of 13 reference points are used for calculation. Please refer to the table above. The nine grids in the middle of each table correspond to the brightness of the nine blocks divided by the nine-square grid, and the outermost four grids correspond to one-tenth of the distance between the four corners and the center point. The brightness value at the corner position. In addition, ANSI light uniformity is the minimum value of the relative brightness corresponding to the four corners divided by the average value of the relative brightness of the nine points divided by the nine-square grid. It can be seen from the above table that when both a transmissive screen and an aspheric surface are provided, the ANSI light uniformity value of the projection device of this embodiment can be closer to 100%, that is, closer to the optimal brightness uniformity.

Fig. 8 is a light energy distribution diagram corresponding to each light spot on the image plane or the active surface in the first embodiment of the present invention, wherein the coordinates shown on the top of Fig. 8 are the image plane or the active surface corresponding to each line The coordinate points of the surface. In other words, each coordinate point at the top of Fig. 8 is the center point of a light spot, the horizontal axis represents the radius relative to the center point of the light spot, and the vertical axis represents the energy contained in the circular area drawn with the above-mentioned radius. The ratio of the total spot energy, and the center of the above-mentioned circular area is also located at the center point of the spot. Referring to Figure 8, it can be seen that on the image plane or the active surface, the radius of the circular area where 50% to 95% of the total energy is distributed in the central spot represented by the data line with the center coordinates (0.000, 0.000) is relatively small. The radius of the circular area corresponding to the other eight edge light spots is larger.

Fig. 9 is a partial schematic diagram of a projection device in another embodiment of the present invention. In this embodiment, referring to FIG. 1 and FIG. 9, the active surface of the projection device 600 from the object plane to the light valve 670 has a first lens 610, a second lens 620, a third lens 630, a mirror 640, a The spherical lens 650 and the internal total reflection prism 660, the illumination light beam L2 also penetrates from the object plane to the light valve 670 according to the order of the above-mentioned optical elements, wherein the first lens 610 has a first surface S1 and a second surface S2, The second lens 620 has a third surface S3 and a fourth surface S4, the third lens 630 has a fifth surface S5 and a sixth surface S6, the mirror 640 has a reflective surface, and the aspheric lens 650 has a first aspheric surface S7 and a second aspheric surface. Aspheric surface S8, while the first lens 610 is a concave-convex lens with a convex surface (second surface S2) facing away from the object plane, the second lens 620 is a convex-concave lens with a convex surface (fourth surface S4) facing away from the object plane, and the third lens 630 is Bi-convex lens, the second aspheric surface S8 of the aspheric lens 650 faces the active surface. The following content will cite an embodiment of the projection device 600, wherein the aspheric coefficients A1, A2, A3, A4, A5 can also refer to the above-mentioned aspheric formula

$\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; cy</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; ,</span>$

The surface S10 of the total internal reflection prism 660 is not shown in Fig. 9, and the surface S10 is the internal total reflection surface of the internal total reflection prism 660, and the data listed in the following Table 1, Table 2 and Table 3 It is not intended to limit the utility model, and anyone with ordinary knowledge in the technical field may make appropriate changes to its parameters or settings after referring to the utility model, but it should still fall within the scope of the utility model.

(Table I)

(Table II)

(Table 3)

In Table 1, Table 2 and Table 3 above, the spacing refers to the linear distance between two adjacent surfaces on the optical axis. For example, the spacing of surface S1 is the distance between surface S1 and surface S2 on optical axis B. Straight line distance. The semi-diameter refers to half of the pore diameter of a surface.

Fig. 10 is a partial schematic diagram of a projection device in another embodiment of the present invention. Please refer to Fig. 10, in the present embodiment, the projection device 700 has a lens 710, a lens 720, a lens 730, a lens 750 and a mirror 740. In the embodiment, for example, it is the curvature radius distribution of the aspheric surface 122 or the aspheric surface 124 . Therefore, according to the distribution of the radius of curvature of the reflective surface of the reflective mirror 740 in this embodiment, the reflected illumination light beam L2 can have the characteristic that the edge brightness is greater than the center brightness in the brightness distribution.

To sum up, in the embodiment of the present invention, the design of the aspheric surface in the refractive element group allows a surface light source to have a brightness distribution at the edge that is greater than that at the center when it reaches an image plane or the active surface of a light valve. properties of brightness. In more detail, in the embodiment of the present invention, the aspherical surface can provide a light beam whose brightness gradually increases from the center to the edge of the brightness distribution, and when projected onto a transmissive screen, the edge area of the screen can be compensated due to the incident angle. The impact of uneven brightness distribution caused by the larger brightness, and then provide images with the best brightness uniformity; the projection device in the utility model is a rear projection display, which can be applied to at least two groups of rear projection displays. The video wall system uses the light beams projected by each projection device to have the characteristic that the edge brightness is greater than the central brightness in brightness distribution, and forms an image with uniform brightness through the compensation of the corresponding penetrating screen, so that The spliced display system also has a spliced video image with uniform brightness.

Although the utility model has been disclosed as above with the embodiment, it is not intended to limit the utility model. Anyone with ordinary knowledge in the technical field can make some changes without departing from the spirit and scope of the utility model. and retouching, so the scope of protection of the present utility model should be defined by the appended claims as the criterion.

List of reference signs

B: optical axis

h, γ: distance

d1, d2, d3: direction

E: Straight line

L ₁ , L ₂ : Lighting beam

L ₃ : image beam

L ₄ , L ₅ : light beam

S1, S2, S3, S4, S5, S6, S7, S8, S9: surface

100: lighting system

110: Light source module

112: Light emitting element

114: Light homogenizing element

116: light output side

120: Refractive element group

121: object plane

122, 124: aspherical surface

123: Image plane

130: central spot

132: edge flare

210A, 210B, 210C, 210D, 210E, 220, 222, 610, 620, 630, 650, 710,

720, 730, 750: lens

223: Active surface

300: projection device

310, 670: light valve

320: projection lens

330: internal total reflection prism

340: Penetrating screen

342: Fresnel lens surface

344: Cylindrical lens surface

401, 402, 403, 408, 405, 406, 407, 408, 409: light field

501, 502, 503, 504, 505, 506, 507, 508, 509: spot distribution diagram

640, 740: Mirror

650: Aspherical lens

Claims (24)

1. A lighting system, comprising: a light source module and a diopter group, wherein, The light source module provides a light source on an object plane, and The refractive element group projects the surface light source on the object plane onto an image plane, wherein the refractive element group has an aspherical surface, so that a point on the surface light source is in the image plane The root-mean-square radius of a central spot generated at the intersection of the plane and an optical axis of the refractive element group is larger than the root-mean-square radius of multiple edge spots produced by other points on the surface light source at the edge of the image plane average value. 2. The lighting system according to claim 1, wherein the dioptric element group includes a plurality of lenses arranged from the object plane to the image plane, and the lens closest to the image plane The surface of the lens facing the image plane is the aspheric surface, or the surface of the lens closest to the object plane facing the object plane is the aspheric surface. 3. The lighting system according to claim 1, wherein the light source module comprises: a light-emitting element and a light-homogenizing element, the light-emitting element is used to emit an illumination beam, and the light-homogenizing element is configured On the transmission path of the illuminating light beam, the object plane is located on the light emitting side of the light homogenizing element. 4. The lighting system according to claim 1, wherein the geometric spot radius of the central spot is larger than the average value of the geometric spot radii of the plurality of edge spots. 5. The lighting system according to claim 1, characterized in that: the lighting system satisfies I ₁ /I ₀ >1.05, where I ₀ is the intersection of the image plane and the optical axis of the dioptric element group , and I ₁ is the relative illuminance at the edge of the image plane. 6. The lighting system according to claim 1, wherein the central light spot and the plurality of edge light spots each have a circular area, and the centers of the plurality of circular areas are respectively located at the central light spot and the plurality of edge light spots. The central point of the plurality of edge light spots, and the light energy in the circular area of the central light spot accounts for α% of the total light energy of the central light spot, and each of the plurality of edge light spots The light energy contained in the circular area of the plurality of edge spots accounts for α% of the total light energy of the edge spots, wherein the radius of the circular area of the central spot is larger than that of each of the plurality of edge spots The radius of the circular area, and 50≤α≤95. 7. The lighting system according to claim 1, wherein the portion of the aspheric surface close to the optical axis of the dioptric element group is a curved concave surface, and the portion of the aspheric surface far away from the diopter The part of the optical axis of the optical element group is a ring-shaped curved convex surface surrounding the curved concave surface. 8. The lighting system according to claim 1, characterized in that: the part of the aspheric surface close to the optical axis of the refractive element group is a slightly convex surface, and the aspheric surface The portion away from the optical axis of the diopter group is an annular curved convex surface surrounding the slightly convex surface. 9. The lighting system according to claim 8, characterized in that: the offset ratio of each point on the aspheric surface with an R value of 0.3 is less than 0.1, and the offset ratio of each point on the aspheric surface with an R value of 0.5 The displacement ratio is less than 0.2, and the displacement ratio of each point on the aspheric surface with an R value of 0.7 is less than 0.5, wherein the R value of a point on the aspheric surface is the distance between the point and the optical axis and the The ratio of the maximum distance between the aspheric surface and the optical axis, the ratio of the offset of the point is the offset of the point in the direction of the aspheric surface in the direction of the optical axis to the direction of the aspheric surface in the direction of the optical axis The ratio of the maximum offset of . 10. The lighting system according to claim 1, characterized in that: the aspheric surface conforms to the aspheric surface formula $\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; cy</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; ,</span>$ Where Z is the offset in the direction of the optical axis of the aspheric surface, c is the reciprocal of the radius of the close sphere, K is the quadratic surface coefficient, and y is the offset in the direction perpendicular to the optical axis of the aspheric surface A ₁ , A ₂ , A ₃ , A ₄ , A ₅ are aspherical coefficients, among which -0.025<c<-0.005 and -500<K<-40, aspheric coefficients A ₁ , A ₂ , A ₃ At least one of , A ₄ , A ₅ is opposite to the sign of c, the Z value corresponding to the position of y=0 of the aspheric surface is not the maximum value, and the aspheric surface includes a position with a slope of 0 , the position where the slope is 0 refers to the position where the first derivative of Z relative to y is 0, and the position where the slope is 0 falls at y=0.3γ to y=0.7γ, where γ is the The maximum distance of the aspheric surface in the y direction relative to the optical axis. 11. The lighting system according to claim 1, wherein the dioptric element group comprises at least one reflector, and the aspheric surface is a reflective surface of the reflector. 12. A projection device, comprising: a light valve, an illumination system, a projection lens and a transmissive screen, wherein the illumination system comprises: a light source module; and a diopter group, wherein the light source module A surface light source is provided on an object plane, and the set of diopters projects the surface light source on the object plane onto an active surface of the light valve, and the set of diopters has a non- Spherical surface, so that the root mean square radius of a central light spot generated by a point on the surface light source at the intersection of the active surface and an optical axis of the refractive element group is greater than that of other points on the surface light source on the said surface light source an average of the root-mean-square radii of the plurality of edge spots produced by the edge of the active surface on which the light valve converts the surface light source into an image beam, and The projection lens is arranged on the transmission path of the image beam, and the transmissive screen is arranged on the transmission path of the image beam from the projection lens. 13. The projection device according to claim 12, wherein the dioptric element group includes a plurality of lenses arranged from the object plane to the active surface, and the lens closest to the active surface The surface of the lens facing the active surface is the aspheric surface, or the surface of the lens closest to the object plane facing the object plane is the aspheric surface. 14. The projection device according to claim 12, wherein the light source module comprises: a light emitting element and a light homogenizing element, wherein the light emitting element is used to emit an illuminating beam, and the light homogenizing element The element is arranged on the transmission path of the illumination light beam, wherein the object plane is located on the light emitting side of the light homogenizing element. 15. The projection device according to claim 12, wherein the geometric spot radius of the central spot is larger than the average value of the geometric spot radii of the plurality of edge spots. 16. The projection device according to claim 12, characterized in that: the projection device satisfies I ₁ /I ₀ >1.05, wherein I ₀ is the intersection of the active surface and the optical axis of the dioptric element group The relative illuminance at , and I ₁ is the relative illuminance at the edge of the active surface. 17. The projection device according to claim 12, wherein the central spot and the plurality of edge spots each have a circular area, and the centers of the plurality of circular areas are respectively located at the central spot and the plurality of edge spots. The central point of the plurality of edge light spots, and the light energy in the circular area of the central light spot accounts for α% of the total light energy of the central light spot, and each of the plurality of edge light spots The light energy contained in the circular area of the plurality of edge spots accounts for α% of the total light energy of the edge spots, wherein the radius of the circular area of the central spot is larger than that of each of the plurality of edge spots The radius of the circular area, and 50≤α≤95. 18. The projection device according to claim 12, characterized in that: the portion of the aspheric surface close to the optical axis of the dioptric element group is a curved concave surface, and the portion of the aspheric surface far away from the diopter The part of the optical axis of the optical element group is a ring-shaped curved convex surface surrounding the curved concave surface. 19. The projection device according to claim 12, wherein the portion of the aspheric surface close to the optical axis of the refractive element group is a slightly convex surface, and the portion of the aspheric surface The portion away from the optical axis of the diopter group is an annular curved convex surface surrounding the slightly convex surface. 20. The projection device according to claim 19, characterized in that: the offset ratio of each point on the aspheric surface with an R value of 0.3 is less than 0.1, and the offset ratio of each point on the aspheric surface with an R value of 0.5 The displacement ratio is less than 0.2, and the displacement ratio of each point on the aspheric surface with an R value of 0.7 is less than 0.5, wherein the R value of a point on the aspheric surface is the distance between the point and the optical axis and the The ratio of the maximum distance between the aspheric surface and the optical axis, the ratio of the offset of the point is the offset of the point in the direction of the aspheric surface in the direction of the optical axis to the direction of the aspheric surface in the direction of the optical axis The ratio of the maximum offset. 21. The projection device according to claim 12, characterized in that: the aspherical surface conforms to the aspheric surface formula $\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; cy</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; ,</span>$ Where Z is the offset in the direction of the optical axis of the aspheric surface, c is the reciprocal of the radius of the close spherical surface, K is the quadratic surface coefficient, and y is the deviation in the direction perpendicular to the optical axis of the aspheric surface displacement, and A ₁ , A ₂ , A ₃ , A ₄ , A ₅ are aspheric coefficients, -0.025<c<-0.005 and -500<K<-40, aspheric coefficients A ₁ , A ₂ , A ₃ At least one of , A ₄ , A ₅ is opposite to the sign of c, the Z value corresponding to the position of y=0 of the aspheric surface is not the maximum value, and the aspheric surface includes a position with a slope of 0 , the position where the slope is 0 refers to the position where the first derivative of Z relative to y is 0, and the position where the slope is 0 falls at y=0.3γ to y=0.7γ, where γ is the The maximum distance of the aspheric surface in the y direction relative to the optical axis. 22. The projection device according to claim 12, wherein the refractive element group comprises at least one mirror, and the aspheric surface is a reflective surface of the mirror. 23. The projection device according to claim 12, wherein the transmissive screen comprises: a Fresnel lens surface and a lenticular lens surface, wherein the Fresnel lens surface is configured on the image beam on the transmission path of the cylindrical lens surface, and the surface of the lenticular lens is configured on the transmission path of the image beam from the surface of the Fresnel lens, wherein the surface of the lenticular lens has a plurality of lenticular microlens structures, each of the multiple A columnar microlens structure extends along a first direction, and the plurality of columnar microlens structures are arranged along a second direction. 24. The projection device according to claim 12, further comprising an internal total reflection prism, arranged on the optical path between the refractive element group and the light valve, and arranged on the image beam on the transmission path and between the light valve and the projection lens.