Projection light machine

Abstract

The embodiment of the present disclosure discloses a projection light machine. The projection light machine comprises a light machine main body, a prism assembly and a heat dissipation device; the light machine main body is internally provided with a containing space; the prism assembly is arranged in the containing space, the prism assembly comprises a prism body and a light shielding layer, the prism body has an incident surface, an emitting surface and a coupling surface, and the light shielding layer is bonded at the position where the incident surface intersects with the emitting surface; the heat dissipation device is arranged outside the light machine main body, and the heat dissipation device is in contact with the prism assembly.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more specifically, to a projection optical engine. Background Technology

[0002] The light inside a projection optical engine typically consists of active light and stray light. A portion of the active light is used for imaging, while the remaining portion is not needed for imaging, i.e., non-imaging light. Non-imaging light is the portion of light separated from the active light. This non-imaging light is absorbed within the optical engine and converted into heat, which raises the temperature of the lenses, prisms, and the main body. Therefore, if the heat is not properly managed, it can easily lead to deformation and burning of the plastic lenses / main body, and negative effects such as thermal defocusing. Especially with the increasing brightness and miniaturization of current optical engines, the light energy processing of the prisms and the preceding lens, as the output area for non-imaging light, is particularly critical.

[0003] Therefore, a technical solution is needed to solve the above-mentioned technical problems. Summary of the Invention

[0004] One object of the present invention is to provide a new technical solution for a projection optical engine.

[0005] According to a first aspect of the present invention, a projection optical engine is provided. The projection optical engine includes an optical engine body, a prism assembly, and a heat dissipation device. A receiving space is provided within the optical engine body. The prism assembly is disposed within the receiving space. The prism assembly includes a prism body and a light-shielding layer. The prism body has an incident surface, an exit surface, and a coupling surface. The light-shielding layer is adhered to the position where the incident surface and the exit surface intersect. The heat dissipation device is disposed outside the optical engine body. The heat dissipation device is in contact with the prism assembly.

[0006] Optionally, the light-shielding layer is disposed around the edge of the incident surface and / or the edge of the exit surface.

[0007] Optionally, a rectangular hole is formed in the center of the light-shielding layer. The rectangular hole has a chamfer at at least one corner near the junction of the incident surface and the exit surface.

[0008] Optionally, the light-shielding layer is disposed around the edges of the incident surface and the exit surface. The light-shielding layer forms a single integral structure.

[0009] Optionally, a through-hole is provided at the bottom of the optical engine body. The shape of the through-hole matches the shape of the bottom of the prism body. The heat dissipation device has a heat dissipation protrusion. The heat dissipation protrusion is embedded in the through-hole. The prism assembly also includes a thermally conductive layer. The thermally conductive layer is located between the heat dissipation protrusion and the bottom of the prism assembly. The heat dissipation protrusion is in contact with the thermally conductive layer.

[0010] Optionally, the thermally conductive layer is bonded to the bottom of the prism body. The heat dissipation protrusion is bonded to the thermally conductive layer. A sealing material is provided around the through hole at the bottom of the optomechanical body. The sealing material is sealed between the bottom of the prism body and the bottom of the optomechanical body.

[0011] Optionally, the thermally conductive layer has an extension 224 located at the bottom of the prism body. The extension 224 is in contact with the light-shielding layer.

[0012] Optionally, the thermally conductive layer is at least one of thermally conductive silicone, thermally conductive grease, and thermally conductive liquid.

[0013] Optionally, the optical engine body includes a bottom and a sidewall portion connected to the bottom. The light-shielding layer is bonded to the exit surface. The light-shielding layer is bonded to the sidewall portion.

[0014] Optionally, the light-shielding layer includes a substrate layer and a light-absorbing layer attached to the surface of the substrate layer. The light-absorbing layer is at least one of a metal, thermally conductive fiber, and thermally conductive silicone. Alternatively, the light-absorbing layer may be at least one of an anodized layer and an ink.

[0015] Optionally, the heat dissipation device is fixed to the bottom of the optical engine body by bolts. An elastic element is provided on the sleeve of the bolt thread.

[0016] One technical effect of this invention is that the light-shielding layer is bonded to the position where the incident and exit surfaces of the prism body intersect, which can effectively absorb non-imaging light, thereby significantly improving the imaging effect of the projection optical engine.

[0017] In addition, the light-shielding layer is bonded to the prism body. Compared with the implementation method of setting the shielding structure on the optical engine body, this method can effectively avoid the prism body being damaged by the shielding structure during the assembly of the projection optical engine.

[0018] In addition, the heat dissipation device is in contact with the prism assembly, which can effectively release the heat of the prism assembly to achieve the purpose of heat dissipation.

[0019] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0021] Figure 1 This is a schematic diagram of the disassembled state of an embodiment of the present invention.

[0022] Figure 2This is a schematic diagram of the combined state according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the combined state from another angle in an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the prism assembly and the optomechanical body in an exploded state according to an embodiment of the present invention.

[0025] Figure 5 This is an exploded view of the heat dissipation device according to an embodiment of the present invention.

[0026] Figure 6 This is a schematic diagram of the combined state of the heat dissipation device according to an embodiment of the present invention.

[0027] Figure 7 This is a schematic diagram of the cross-sectional structure of the light-shielding layer according to an embodiment of the present invention.

[0028] In the figure, 1-Optical engine body; 11-Accommodation space; 12-Through hole; 13-Bottom; 14-Side wall; 15-Cover plate; 2-Prism assembly; 21-Prism body; 211-Incident surface; 212-Exit surface; 213-Coupling surface; 22-Light-shielding layer; 221-Substrate layer; 222-Light-absorbing layer; 223-Rectangular hole; 2231-Incident hole; 2232-Exit hole; 224-Extension; 23-Heat-conducting layer; 3-Heat dissipation device; 31-Heat dissipation protrusion; 32-Sealing material; 33-Elastic element; 34-Heat dissipation fin; 4-Lens. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0030] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0031] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0032] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0034] This disclosure provides a projection optical engine. The projection optical engine is used to project video, images, etc. The projection optical engine includes an optical engine body 1, a prism assembly 2, and a heat dissipation device 3. A receiving space 11 is provided within the optical engine body 1. The prism assembly 2 is disposed within the receiving space 11. The prism assembly 2 includes a prism body 21 and a light-shielding layer 22. The prism body 21 has an incident surface 211, an exit surface 212, and a coupling surface 213. The light-shielding layer 22 is adhered to the position where the incident surface 211 and the exit surface 212 intersect. The heat dissipation device 3 is disposed outside the optical engine body 1. The heat dissipation device 3 is in contact with the prism assembly 2.

[0035] In this embodiment, the light-shielding layer is bonded to the intersection of the incident and exit surfaces of the prism body. The light-shielding layer effectively absorbs non-imaging light, thereby significantly improving the imaging effect of the projection optical engine.

[0036] In addition, the light-shielding layer is bonded to the prism body. Compared with the implementation method of setting the shielding structure on the optical engine body, this method can effectively avoid the prism body being damaged by the shielding structure during the assembly of the projection optical engine.

[0037] In addition, the heat dissipation device is in contact with the prism assembly, which effectively releases the heat from the prism assembly to achieve the purpose of heat dissipation.

[0038] Specifically, such as Figures 1 to 3 As shown, the optical engine body 1 is a box-shaped structure with openings on its top and front surfaces. These openings are used for either emitting or receiving light. For example, the optical engine body 1 has an overall rectangular parallelepiped structure. A cover plate 15 is provided on the top of the optical engine body 1. The cover plate 15 is connected to the optical engine body 1 by bolts. The cover plate 15 effectively blocks external light. The optical engine body 1 and the cover plate 15 are made of materials such as plastic, metal, or rubber.

[0039] The incident surface 211 of the prism body 2 is the surface on which light enters. The exit surface 212 is the surface on which the processed light finally exits. The coupling surface 213 is the surface on which the light exits, reaches the DMD chip, and is then coupled by the DMD chip. After coupling, the light is reflected and enters the prism body 21 through the coupling surface 213. For example, the prism body 21 is a triangular prism, a multi-prism, etc. The material of the prism body 21 is glass, plastic, etc. A light-shielding layer 22 is bonded at the intersection of the incident surface 211 and the exit surface 212. This intersection is the area of ​​the incident surface 211 near the intersecting edge of the incident surface 211 and the exit surface 212, and / or the area of ​​the exit surface 212 near the intersecting edge of the incident surface 211 and the exit surface 212. For example, the light-shielding layer 22 is bonded to the intersection with adhesive.

[0040] During operation, light emitted from the light source passes through lens 4 and is projected onto the incident surface 211 of the prism body 21. The light-shielding layer 22 of the incident surface 211 effectively blocks stray light from hitting the prism body 21. The light is refracted through the incident surface 211 to the coupling surface 213 and then exits from the coupling surface 213 to the DMD chip. The light processed by the DMD chip is reflected back to the coupling surface 213 to enter the prism body 21, where it undergoes total internal reflection. Finally, the effective imaging light is projected through the exit surface 212. Non-imaging light is directed towards the intersection of the incident surface 211 and the exit surface 212. The non-imaging light projected into the prism body 21 is effectively absorbed by the light-shielding layer 22 at the incident surface 211 and the exit surface 212, thereby improving the projection effect of the projection engine.

[0041] The heat dissipation device 3 is a finned heat sink, heat sink plate, etc. The heat dissipation device 3 is in contact with the bottom surface of the prism assembly. The heat dissipation device 3 can effectively reduce the temperature of the prism assembly 2 and improve the reliability of the projection optical engine.

[0042] In one example, the light-shielding layer 22 is disposed around the edge of the incident surface 211 and / or the edge of the exit surface 212.

[0043] like Figure 3 As shown, the prism body 21 is a triangular prism. The cross-section of the triangular prism is a right-angled triangle. The incident surface 211 is located on the hypotenuse of the right-angled triangle. The coupling surface 313 is located on one of the right-angled sides of the right-angled triangle. The exit surface 212 is located on the other hypotenuse of the right-angled triangle. The incident surface 211, the exit surface 212, and the coupling surface 213 are all rectangular. A light-shielding layer 22 is bonded to the edge of the incident surface 211. For example, the light-shielding layer 22 is bonded to the edge of the incident surface 211 with adhesive. Since the light-shielding layer 22 is located at the edge of the incident surface 211, the side of the light-shielding layer 22 near the lens 4 can effectively block the stray light from entering the incident surface 211. The side of the light-shielding layer 22 away from the lens 4 can absorb the non-imaging light entering the triangular prism from the coupling surface 213. Non-imaging light is effectively blocked and absorbed by the light-shielding layer 22 bonded at the edge of the exit surface 212 and the light-shielding layer 22 at the intersection of the incident surface 211 and the exit surface 212. Since the light-shielding layer 22 is located at the edge of the exit surface 212, the light-shielding layer 22 can effectively absorb stray light from the coupling surface 213 and / or total internal reflection from the incident surface 211.

[0044] Alternatively, a light-shielding layer 22 may be provided only on the incident surface 211 or the exit surface 212.

[0045] Of course, the location of the light-shielding layer 22 is not limited to the above embodiment, and those skilled in the art can choose according to actual needs.

[0046] In one example, a rectangular hole 223 is formed in the center of the light-shielding layer 22. The rectangular hole 223 has a chamfer at at least one corner near the junction of the incident surface 211 and the exit surface 212.

[0047] like Figure 1 and Figure 4 As shown, a light-shielding layer 22 is provided on the incident surface 211 and the exit surface 212. An incident aperture 22311 is provided in the middle of the light-shielding layer 22 on the incident surface 211. The incident aperture 22311 is used for light to enter the prism body 21. An exit aperture 2232 is provided in the middle of the light-shielding layer 22 on the exit surface 212. The exit aperture 2232 is used for emitting processed imaging light. Chamfers are provided on the incident aperture 2231 and the exit aperture 2232. The chamfers are either rounded or beveled. Compared to right angles, chamfers can significantly increase the area of ​​the light-shielding layer 22. The increased area of ​​the light-shielding layer 22 can better block and absorb stray light and non-imaging light, resulting in better projection effect.

[0048] In one example, the light-shielding layer 22 is disposed around the edge of the incident surface 211 and the edge of the exit surface 212. The light-shielding layer 22 forms a single integral structure.

[0049] like Figure 1 and Figure 4 As shown, the light-shielding layer 22 has an overall V-shaped structure. The light-shielding layer 22 is bonded to the incident surface 211 and the exit surface 212. The V-shaped structure of the light-shielding layer 22 allows for better coverage and shielding of the prism body 21. The light-shielding layer 22 is a single piece to avoid seams at the corners, which could lead to inadequate shielding and poor light-shielding effect.

[0050] For example, the material used to prepare the light-shielding layer 22 is a sheet. The entrance hole 2231 and the exit hole 2232 are integrally formed by stamping, and then bent to form a V-shaped light-shielding layer 22.

[0051] In this example, the integrated light-shielding layer 22 is easy to process and install, and the portion of the light-shielding layer 22 located on the incident surface 211 and the exit surface 212 is precisely positioned.

[0052] Of course, the structure and shape of the light-shielding layer 22 are not limited to the above embodiments, and those skilled in the art can choose according to actual needs.

[0053] In one example, a through-hole 12 is provided at the bottom of the optical engine body 1. The shape of the through-hole 12 matches the shape of the bottom of the prism body 21. The heat dissipation device 3 has a heat dissipation protrusion 31. The heat dissipation protrusion 31 is embedded in the through-hole 12, and the prism assembly 2 further includes a thermally conductive layer 23. The thermally conductive layer 23 is located between the heat dissipation protrusion 31 and the bottom of the prism assembly 2. The heat dissipation protrusion 31 is in contact with the thermally conductive layer 23.

[0054] like Figure 1 , Figure 5 and Figure 6 As shown, the through-hole 12 is a right-angled triangle. The lateral dimension of the prism body 21 is larger than that of the through-hole 12, so that the edge of the prism body 21 can be sealed around the through-hole 12. A heat sink 34 is bolted to the bottom of the optical engine body 1. A heat dissipation protrusion 31 is formed on the side of the heat sink 34 near the prism assembly 2. The heat dissipation protrusion 31 is in contact with the heat-conducting layer 23. The heat-conducting layer 23 can effectively conduct heat, thereby transferring the heat of the prism assembly 2 to the heat sink 34. The heat released by the lens 4 and the prism assembly 2 during operation causes the temperature of the optical engine body 1 to rise. The heat sink 34 can dissipate some of the heat of the optical engine body 1. The heat dissipation protrusion 31 on the heat sink 34 is embedded in the through-hole 12 at the bottom of the optical engine body 1 and is in contact with the heat-conducting layer 23 of the prism assembly 2, so that the heat is dissipated more quickly and effectively, thereby dissipating heat from the optical engine body 1 and the prism assembly 2 more quickly and effectively.

[0055] In one example, the thermally conductive layer 23 is bonded to the bottom of the prism body 21. The heat dissipation protrusion 31 is bonded to the thermally conductive layer 23. A sealing material 32 is provided around the through hole 12 at the bottom of the optomechanical body 1. The sealing material 32 is used to seal the space between the bottom of the prism body 21 and the bottom of the optomechanical body 1.

[0056] like Figures 5 to 6 As shown, the top of the heat-conducting layer 23 is bonded to the prism body 21. The bottom of the heat-conducting layer 23 is bonded to the heat dissipation protrusion 31. The prism body 21 and the heat dissipation protrusion 31 are connected through the heat-conducting layer 23 to accelerate the heat dissipation from the prism body 21 and reduce the heat of the projection optical engine. Typically, the adhesive used to bond the heat-conducting layer 23 contains volatile organic compounds (VOCs). These VOCs can contaminate equipment inside the optical engine body 1, such as lenses. By sealing the heat-conducting layer 23 within the through-hole 12 with the sealing material 32, the volatilization of VOCs into the containment space can be prevented, thereby reducing contamination and damage to the equipment. The sealing material 32 is located at the bottom of the prism body 21 and the bottom of the optical engine body 1, and does not obstruct the heat dissipation and exhaust.

[0057] In one example, the thermally conductive layer 23 has an extension 224 located at the bottom of the prism body 21. The extension 224 is in contact with the light-shielding layer 22.

[0058] For example, the light-shielding layer 22 is bonded to the prism body 21. The light-shielding layer 22 is bent at the bottom of the prism body 21 to form an extension 224. During operation, the heat generated by the prism body 21 and the heat generated by the light-shielding layer 22 blocking and absorbing light causes the temperature of the light-shielding layer 22 to rise. The extension 224 of the heat-conducting layer 23 comes into contact with the light-shielding layer 22, allowing heat to be directly transferred to the heat-conducting layer 23, accelerating heat dissipation. The heat is then dissipated through the heat-conducting layer 23, thereby reducing the temperature of the projection optical engine.

[0059] Of course, those skilled in the art can set the length of the extension 224 according to actual needs.

[0060] In one example, the thermally conductive layer 23 is at least one of thermally conductive silicone, thermally conductive grease, and thermally conductive liquid.

[0061] The thermally conductive layer 23 has a certain degree of adhesion to bond the prism body 21 and the heat dissipation protrusion 31. The thermally conductive layer 23 is bonded to both the prism body 21 and the heat dissipation protrusion 31 to accelerate the conduction and dissipation of heat.

[0062] Of course, the material of the heat-conducting layer 23 is not limited to the above embodiments, and those skilled in the art can choose according to actual needs.

[0063] In one example, the optical engine body 1 includes a bottom 13 and a sidewall portion 14 connected to the bottom. The light-shielding layer 22 is bonded to the emission surface 212. The light-shielding layer 22 is bonded to the sidewall portion 14.

[0064] like Figures 1 to 3 As shown, the top and sidewall portions 14 form a receiving cavity. The sidewall portion 14 has an opening. A cover plate 15 is bolted to the top of the optical engine body 1. The cover plate 15 is a metal plate or a plastic plate, etc. One side of the light-shielding layer 22 is bonded to the exit surface 212 with an adhesive material. The other side of the light-shielding layer 22 is bonded to the sidewall portion 14 with an adhesive material. The prism assembly 21 is connected to the sidewall portion 14 of the optical engine body 1 with an adhesive material. In this way, the light-shielding layer 22 serves both to absorb non-imaging light and stray light and to fix the prism assembly 21, thereby preventing the position of the prism assembly 21 from moving during installation or operation and affecting the projection effect.

[0065] In one example, the light-shielding layer 22 includes a substrate layer 221 and a light-absorbing layer 222 attached to the surface of the substrate layer 221. The light-absorbing layer 222 is at least one of a metal, a thermally conductive fiber, and a thermally conductive silicone. The light-absorbing layer 222 is at least one of an anodized layer and an ink.

[0066] For example, the substrate layer 221 is made of materials such as copper, aluminum, or light-shielding sheets. The light-absorbing layer 222 is ink coated on the surface of the substrate layer. The ink can effectively absorb non-imaging light and stray light.

[0067] Alternatively, the substrate layer 221 can be a metal sheet, with an anodized layer formed on the surface of the metal sheet through anodizing. The anodized layer can effectively absorb non-imaging light and stray light.

[0068] The aforementioned substrate layer 221 can effectively transfer heat. The light-absorbing layer can intercept and absorb stray light and non-imaging light at the prism assembly 2, and the light-shielding layer 22 can conduct heat out of the prism assembly 2 to reduce the heat of the projection optical engine and improve the overall performance of the projection optical engine.

[0069] In one example, the heat dissipation device 3 is fixed to the bottom of the optical engine body 1 by bolts. An elastic element 33 is provided on the sleeve of the bolt thread.

[0070] The elastic element 33 is made of elastic material such as a spring or rubber pad. The heat dissipation protrusion 31 is embedded in the through hole of the optical engine body 1. The heat dissipation protrusion 31 is connected to the bottom of the prism body 21 through the heat-conducting layer 23. When the heat sink 34 is connected to the optical engine body 1, the elastic element 33 can provide a certain buffer space for the heat dissipation protrusion 31 in the through hole, so as to prevent the prism body 21 from being pushed into misalignment by the heat dissipation protrusion 31 during installation.

[0071] In one example, the assembly of the projection optical engine includes the following steps:

[0072] Step 1: Bond the prism body 21 together with the light-shielding layer 22 and the heat-conducting layer 23 to form the prism assembly 2. The light-shielding layer 22 is bonded to the edges of the incident surface 211 and the exit surface 212 of the prism body 21. The heat-conducting layer 23 is bonded to the bottom of the prism body 21.

[0073] Step 2: Attach the prism assembly 2 to the receiving space 11 of the optical engine body 1. The light-shielding layer 22 is glued to the side wall 14 of the optical engine body 1. The heat-conducting layer 23 is opposite to the through-hole 12.

[0074] Step 3: Insert the heat dissipation protrusion 31 of the heat dissipation device 3 into the through hole 12 and bond it to the heat-conducting layer 23. The sealing material 32 is clamped between the bottom of the optical engine body 1 and the bottom of the prism body 21. The sealing material 32 is arranged around the through hole 12. Fix the heat dissipation device 3 to the optical engine body 1 with bolts. The bolt shank is fitted with a spring.

[0075] Step 4: Install the lens 4 into the receiving space 11 of the optical engine body 1. The lens 4 is opposite to the incident surface 211 of the prism body 21. Fix the cover plate 15 to the optical engine body 1.

[0076] In this example, the light-shielding layer 22 is first bonded to the prism body 21 to form the prism assembly 2. Finally, the lens 4 is assembled. Furthermore, no baffle is provided on the cover plate 15 to block non-imaging light. Therefore, the lens 4 will not be damaged by the baffle during assembly.

[0077] In addition, the heat dissipation device 3 is fixed by bolts with springs, which can prevent the heat dissipation protrusion 31 from excessively pressing against the prism body 21, thereby preventing the position of the prism body 21 from being tilted.

[0078] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A projection light engine, characterized by, The application relates to a light machine body (1) provided with a containing space (11), a prism assembly (2) provided in the containing space (11), the prism assembly (2) comprising a prism body (21) and a light shielding layer (22), the prism body (21) having an incident surface (211), an emitting surface (212) and a coupling surface (213), the light shielding layer (22) being bonded at the position where the incident surface (211) and the emitting surface (212) intersect, and a heat dissipation device (3) provided outside the light machine body (1) and in contact with the prism assembly (2). The prism assembly (2) further comprises a heat conducting layer (23) located between the heat dissipation device (3) and the bottom of the prism assembly (2), the heat dissipation device (3) being in contact with the heat conducting layer (23); the heat conducting layer (23) has an extension (224) located at the bottom of the prism body (21), the extension (224) being bonded to the prism body (21) and in contact with the light shielding layer (22); the light machine body (1) is made of metal material and comprises a bottom (13) and a side wall (14) connected to the bottom; the light shielding layer (22) bonded to the emitting surface (212) is also bonded to the side wall (14). The bottom of the light machine body (1) is provided with a through hole (12) matching the shape of the bottom of the prism body (21), and the heat dissipation device (3) has a heat dissipation protrusion (31) embedded in the through hole (12) and bonded to the heat conducting layer (23). The light shielding layer (22) surrounds the edges of the incident surface (211) and / or the edges of the emitting surface (212). The middle part of the light shielding layer (22) is formed with a rectangular hole (223), and the rectangular hole (223) is formed with a chamfer at at least one corner position close to the junction of the incident surface (211) and the emitting surface (212). The light shielding layer (22) surrounds the edges of the incident surface (211) and the edges of the emitting surface (212) and forms an integrated structure. The bottom of the light machine body (1) is provided with a sealing material (32) surrounding the through hole (12), and the sealing material (32) seals the space between the bottom of the prism body (21) and the bottom of the light machine body (1).

2. The projection printer according to claim 1, wherein The heat conducting layer (23) is at least one of heat conducting silica gel, heat conducting silicone grease and heat conducting liquid.

3. The projection printer according to claim 2, wherein The light shielding layer (22) comprises a base layer (221) and a light absorbing layer (222) attached to the surface of the base layer (221), the light absorbing layer (222) being at least one of metal, heat conducting fiber and heat conducting silica gel, and the light absorbing layer (222) being at least one of an anodized layer and ink.

4. The projection printer according to claim 2, wherein ​ 5. The projection engine of claim 1, wherein, ​ 6. The projection printer according to claim 1 or 5, wherein ​ 7. The projection printer according to any one of claims 1 to 5, wherein ​ 8. The projection printer according to any one of claims 1 to 5, wherein The heat dissipation device (3) is fixed on the bottom of the optical machine body (1) by a bolt, and an elastic member (33) is sleeved on the screw rod of the bolt.

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