Collimating turning prism, optical module and projection device

Abstract

The embodiment of the present application discloses a collimating and turning prism, an optical module and a projection device. The collimating and turning prism comprises at least a first surface, a second surface and a third surface. A recess is formed on at least a local area of the first surface. The recess is used for receiving incident light and propagating the incident light to the second surface after beam expansion. The second surface is used for total reflection of all the light after beam expansion to collimate all the light into parallel light. The parallel light can be emitted after reflection on the third surface. The technical effect of the embodiment of the present application is to provide a collimating and turning prism which can be applied to an optical path framework. After the collimating and turning prism is introduced, a collimating part, a light combining part and a secondary collimating part in the optical path framework can be omitted, so that the volume of the optical module can be reduced and the compactness of the overall structure of the optical module is improved.

Description

Technical Field

[0001] This application belongs to the field of projection technology, specifically, it relates to a collimation prism, an optical module, and a projection device. Background Technology

[0002] In recent years, Digital Light Processing (DLP) projection devices have developed rapidly, featuring high brightness, high contrast, and high resolution, making them widely applicable. However, in existing technologies, the optical path architecture of DLP projection devices is limited by factors such as the aperture angle and field of view of the imaging optical path, making it difficult to reduce the overall size of the projection device. This results in a relatively large overall size, which fails to meet users' demand for thinner and lighter projection devices. Summary of the Invention

[0003] The purpose of this application is to provide a new technical solution for a collimating and deflecting prism, an optical module, and a projection device, which can effectively reduce the optical path structure size of the optical module.

[0004] According to a first aspect of the embodiments of this application, a collimating deflection prism is provided, the collimating deflection prism including at least a first surface, a second surface and a third surface, wherein at least a local area on the first surface has a recess.

[0005] The recess is used to receive incident light and expand the incident light beam to propagate it to the second surface. The second surface is used to perform total internal reflection on all the expanded light beams to collimate all the light beams into parallel light beams. The parallel light beams can be emitted after total internal reflection on the third surface.

[0006] Optionally, the recess is a spherical or aspherical structure.

[0007] Optionally, the second surface is a freeform surface or an even-order aspherical surface.

[0008] Optionally, the third surface is a Fresnel surface.

[0009] According to a second aspect of the embodiments of this application, an optical module is also provided, including a collimating deflection prism, a light-diffusing element, and a deflection reflection assembly; wherein the light-diffusing element is located between the collimating deflection prism and the deflection reflection assembly;

[0010] The first surface is located on the light-incident side, and the incident light rays enter the recess;

[0011] The light-uniforming element is disposed close to the second surface. After being uniformly processed, the light emitted from the element propagates to the deflection and reflection component, and the light emitted from the deflection and reflection component is projected onto the imaging surface to form an image.

[0012] Optionally, the deflection assembly includes a deflection element and a DMD; wherein the deflection element is located between the light-diffusing element and the DMD.

[0013] Optionally, the turning element includes a second prism and a third prism, wherein two adjacent surfaces of the second prism and the third prism are glued together to form a glued prism group.

[0014] Optionally, the transition element includes at least one freeform prism, the freeform prism including at least a first optical surface near the homogenizing element and a second optical surface near the DMD, both the first optical surface and the second optical surface being freeform surfaces.

[0015] Optionally, the light-diffusing element is a polystyrene lens, which is composed of an array of multiple lens units, wherein each lens unit is a regular hexagon.

[0016] Optionally, a reflective film is provided on the third surface.

[0017] According to a third aspect of the embodiments of this application, a projection device is also provided, including the optical module described in any of the second aspects.

[0018] The beneficial effects of the embodiments of this application are as follows:

[0019] This application provides a collimating and deflecting prism with at least three surfaces. A recess is provided on the first surface, which can be used to expand the incident light beam before it propagates to the second surface. The second surface can collimate the incident light beam, and then the light beam is reflected by the third surface to achieve the convergence and beaming of light of different colors. This allows a single collimating and deflecting prism to replace the independently set collimating part, beam combining part, and secondary collimating part in the optical path structure, which helps to reduce the size of the optical module and improve the overall compactness of the optical module structure.

[0020] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0022] Figure 1 This is a schematic diagram of the collimation and deflection prism provided in an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the structure of an optical module provided in one embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the structure of an optical module provided in another embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the structure of the light-diffusing element provided in the embodiments of this application;

[0026] Figure 5 This is a schematic diagram of the structure of the light source provided in an embodiment of this application.

[0027] Explanation of reference numerals in the attached figures:

[0028] 100, Collimating prism; 101, First surface; 102, Second surface; 103, Third surface; 110, Cavity; 200, Beam homogenizer; 300, Reflection assembly; 310, Reflection element; 311, Second prism; 312, Third prism; 313, Freeform prism; 314, First optical surface; 315, Second optical surface; 320, DMD; 400, Light source. Detailed Implementation

[0029] Various exemplary embodiments of this application 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 this application.

[0030] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and 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] Reference Figure 1 This application provides a collimating deflection prism 100, which includes at least a first surface 101, a second surface 102 and a third surface 103. The first surface 101 is located on the side where light is incident, and at least a local area on the first surface 101 has a recess 110 formed therein.

[0035] The recess 110 receives the incident light and expands the incident light beam before propagating it to the second surface 102. The second surface 102 is used to perform total internal reflection on all the expanded light beams to collimate all the light beams into parallel light beams. The parallel light beams are reflected off the third surface 103 and then emitted.

[0036] Reference Figure 2 The collimating prism 100 has a first surface 101 located on the light-incident side, which is positioned close to the light source 400, which emits incident light. The recess 110 on the first surface 101 is positioned opposite to the light source 400. In other words, the collimating prism 100 has a first surface 101 on the side closest to the light source 400, and the recess 110 is formed on the first surface 101 at a position opposite to the light source 400. The concave surface of the recess 110 faces the light source 400, thus facilitating the entry of incident light emitted from the light source 400 into the collimating prism 100 from the recess 110, while also achieving the beam-expanding effect of the recess 110 on the incident light emitted from the light source 400.

[0037] Reference Figure 1 and Figure 2 The collimating prism 100 includes multiple surfaces, such as the first surface 101, the second surface 102, and the third surface 103 described above. Of course, the collimating prism 100 may also include other surfaces, and this application does not limit this. The first surface 101 is the surface on which the incident light enters the interior of the collimating prism 100, that is... Figure 1 The left surface of the collimating deflection prism 100.

[0038] To diverge the light entering the collimating prism 100 and expand the coverage area of ​​the light entering the collimating prism 100, i.e., to expand the incident light beam, in this embodiment, a recess 110 is formed on the first surface 101 of the collimating prism 100. The effective aperture of the recess 110 is determined according to the range of light beam expansion required in actual use. Therefore, the recess 110 can be formed over the entire area of ​​the first surface 101. Alternatively, the recess 110 can be formed over a localized area of ​​the first surface 101.

[0039] In this embodiment, the second surface 102 of the collimating and deflecting prism 100 has a different orientation than the first surface 101. The second surface 102 is the surface of the collimating and deflecting prism 100 closest to the light-diffusing element 200; the second surface 102 is also the... Figure 2 The upper surface of the collimating deflection prism 100 shown in the figure.

[0040] This application achieves total internal reflection of all light rays propagating to the second surface 102 after being expanded by the recess 110 by configuring the surface shape of the second surface 102. The second surface 102 is, for example, a freeform surface or an even-order aspherical surface. That is, in this embodiment, the second surface 102 achieves total internal reflection of light rays by being configured as a freeform surface or an even-order aspherical surface. Of course, other methods can also be used to achieve total internal reflection of all light rays propagating to the second surface 102 after being expanded by the recess 110.

[0041] In this embodiment, the third surface 103 is the surface of the collimating and deflecting prism 100 away from the light-diffusing element 200, that is... Figure 2 The lower surface of the collimating deflection prism 100 is shown. The third surface 103 is used to reflect the collimated parallel light rays so that the collimated parallel light rays can propagate to the homogenizing element 200.

[0042] It should be noted that the incident light is usually mixed light, that is, the incident light contains light of multiple colors. However, different colors of light have different wavelengths. Therefore, after the incident light is expanded by the recess 110, the refraction angles of different wavelengths of light are different, so the incident light after being expanded by the recess 110 is prone to dispersion. Therefore, in this embodiment of the application, the third surface 103 cooperates with the second surface 102 to converge and combine the collimated parallel light rays, that is, to converge and combine light of different colors.

[0043] This application provides a collimating and deflecting prism 100, which has at least three surfaces. A recess 110 is provided on the first surface 101. The recess 110 can be used to expand the incident light beam and then propagate it to the second surface 102. The second surface 102 can collimate the incident light beam. Then, the light beam is reflected by the third surface 103 to achieve the convergence and beaming of light of different colors. This allows a collimating and deflecting prism 100 to replace the collimating part, the beam combining part and the secondary collimating part that are independently set in the optical path structure, which is beneficial to reduce the volume of the optical module and improve the compactness of the overall structure of the optical module.

[0044] In some examples of this application, the recess 110 is a spherical or aspherical structure.

[0045] In the embodiments of this application, the surface shape of the recess 110 can be designed according to actual needs. Specifically, the recess 110 on the first surface 101 can be a spherical surface or an aspherical surface, and this application does not make a specific limitation on it.

[0046] For example, when the surface of the recess 110 is designed as an even-order aspherical surface, the following surface formula must be satisfied:

[0047]

[0048] Where z is the surface elevation dimension, C is the surface curvature, k is its conic coefficient, r is the radial coordinate determined by the x and y coordinates in the right-hand coordinate system, and a1 to a8 are the surface coefficients to be optimized.

[0049] In this embodiment, the light emitted by the light source 400 can enter the collimating and deflecting prism 100 through the recess 110 on the first surface 101. The light source 400 can be, for example, an LED light source 400.

[0050] Furthermore, the LED light source 400 is a three-in-one light source or a four-in-one light source, that is, the RGB light-emitting chips are set on the same light source 400.

[0051] In a specific example of this application, refer to Figure 5 It adopts a four-in-one light source to emit incident light. When the RGB light-emitting chips are concentrated on the same light-emitting surface, only one collimating and beam combining prism 100 needs to be set in the entire optical module to achieve collimation and beam combining of multiple colors of light at the same time. There is no need to set up a collimation part, beam combining part and secondary collimation part separately, thereby further improving the compactness of the optical module and helping to reduce the overall size of the optical module.

[0052] Optionally, the third surface 103 of the collimating deflection prism 100 is set as a Fresnel surface.

[0053] Reference Figure 3 In this embodiment, light is reflected on the third surface 103. By setting the third surface 103 as a Fresnel surface, while preserving the curvature of the third surface 103, as much optical material as possible can be removed, thus further reducing the overall volume of the collimating deflection prism 100. Specifically, the size of the collimating deflection prism 100 in the longitudinal direction can be reduced. The longitudinal direction specifically refers to the direction in which the DMD320 extends to the third surface 103. This allows for an appropriate reduction in the overall volume of the optical module.

[0054] This application discloses an optical module, which can be used, for example, in a DLP projection device. Compared with existing optical modules, this optical module is small in size, which can reduce the overall size of the projection device and realize a thinner and lighter design.

[0055] Reference Figure 2 and Figure 3 The optical module includes the collimating and deflecting prism 100, the light-diffusing element 200 and the deflecting and reflecting assembly 300 as described above, wherein the light-diffusing element 200 is located between the collimating and deflecting prism 100 and the deflecting and reflecting assembly 300.

[0056] The collimating prism 100 includes at least a first surface 101, a second surface 102 and a third surface 103. The first surface 101 is located on the side where the light is incident, and at least a local area on the first surface 101 has a recess 110 formed therein.

[0057] The light-diffusing element 200 is disposed close to the second surface 102, which is a free-form surface or an even-order aspherical surface.

[0058] The recess 110 receives the incident light and expands it before propagating it to the second surface 102. The second surface 102 is used to perform total internal reflection on all the expanded light rays to collimate them into parallel rays. The parallel rays are reflected by the third surface 103 and then enter the homogenizing element 200. After being homogenized by the homogenizing element 200, the light rays that are emitted after being homogenized propagate to the deflection and reflection assembly 300. The light rays that are emitted after being deflected and reflected by the deflection and reflection assembly 300 are projected onto the imaging surface to form an image.

[0059] It should be noted that by designing the surface shape of the third surface 103 of the aligned turning prism 100, it is possible to reflect light rays that have been totally internally reflected by the second surface 102.

[0060] Of course, the light rays that are totally internally reflected by the second surface 102 can also be reflected by setting a reflective film on the third surface 103 of the collimating and deflecting prism 100. This application does not make specific limitations on this.

[0061] For example, the reflective film can be formed on the third surface 103 of the collimating deflection prism 100 by coating. Alternatively, the reflective film can be attached to the third surface of the collimating deflection prism 100 by optical adhesive.

[0062] The embodiments disclosed in this application improve the optical architecture of the optical module by introducing a collimating and deflecting prism 100 containing multiple surfaces. By cooperating with each surface of the collimating and deflecting prism 100, the collimating part, the light combining part and the secondary collimating part are eliminated in the optical architecture, thereby reducing the volume of the optical module and improving the compactness of the overall structure of the optical module.

[0063] In one embodiment of this application, the deflection assembly 300 includes a deflection element 310 and a DMD 320; wherein the deflection element 310 is located between the light-diffusing element 200 and the DMD 320.

[0064] Among them, DMD320 (Digital Micromirror Device) is a digital micromirror chip. In DLP projection technology, the DMD320 can be used as a key processing element to realize digital optical processing.

[0065] In this embodiment, the desired DMD320 model is first selected, and then the optical expansion formula is applied: U1=π*n1 2 *sin 2 (θ1)*A1, where n1 is the refractive index of the medium material, and n1 = 1 when light propagates in air. θ1 is the light-receiving angle of the DMD320, usually chosen as 180°. A1 is the light-receiving area of ​​the required DMD320 model. After calculation, the optical extension U1 corresponding to the required illumination area of ​​the DMD320 is obtained.

[0066] Then, according to the formula for optical expansion: U2=π*n2 2 *sin 2 (θ2)*A2, where n2 is the refractive index of the medium material, and n1 = 1 when light propagates in air. θ2 is the emission angle of the LED, usually chosen as 180°. A2 is the emitting area of ​​the LED light source 400. To reduce efficiency loss, the optical extension U1 corresponding to the illuminated area of ​​the DMD320 is approximately matched with the optical extension U2 corresponding to the emitting area of ​​the LED light source 400, that is, U2 = U1.

[0067] Therefore, the luminous area A2 of LED light source 400 can be calculated, and then the closest LED model on the market can be determined based on the luminous area A2 of LED light source 400. This establishes the matching relationship between DMD320 and LED light source 400.

[0068] In some examples of this application, reference is made to Figure 1 The transition element 310 includes a second prism 311 and a third prism 312. The two surfaces of the second prism 311 and the third prism 312 are glued together to form a glued prism group.

[0069] In other words, one structural design of the deflection element 310 includes two prisms, namely the second prism 311 and the third prism 312 mentioned above, with the adjacent surfaces of these two prisms bonded together using, for example, optical adhesive, to form a glued prism assembly. The light emitted from the light-diffusing element 200 can be deflected in the deflection element 310, which is beneficial for subsequent projection imaging, improves image clarity, and ensures better image quality.

[0070] It should be noted that, under normal circumstances, the DMD320 is placed at an angle, resulting in an incident tilt angle and optical path difference at different viewing angles. In this embodiment, by setting a second prism 311 as a compensating prism, the second prism 311 and the third prism 312 are combined to compensate for the optical path difference.

[0071] The two surfaces of the second prism 311 and the third prism 312 are glued together to form a glued surface. The light after being homogenized by the light homogenizing element 200 can undergo total internal reflection on this glued surface.

[0072] The bonding surface between the second prism 311 and the third prism 312 should satisfy the following formula:

[0073] n2 = n3 * sin(θ2); where the refractive index of the material of the second prism 311 is n2, the refractive index of the material of the third prism 312 is n3, and θ2 is the incident angle of the reflected light from DMD320 onto the cemented surface.

[0074] In the optical module of this application embodiment, refer to Figure 1 The path of light propagation is as follows:

[0075] Incident light rays enter the collimating and deflecting prism 100 through the recess 110. The recess 110 is used to expand the incident light rays and propagate them to the second surface 102. The second surface 102 performs total internal reflection on all the expanded light rays to collimate them into parallel light rays. The parallel light rays are reflected by the third surface 103 and then enter the homogenizing element 200. After being homogenized by the homogenizing element 200, the outgoing light rays continue to propagate to the deflecting and reflecting assembly 300. The deflecting and reflecting assembly 300 includes a second prism 311 and a third prism 312 bonded together. The light rays exiting the homogenizing element 200 pass through the second prism 311 and the third prism 312 in sequence and enter the DMD 320. After being reflected by the DMD 320, the light rays enter the bonding surface of the second prism 311 and the third prism 312. The light rays undergo total internal reflection at the bonding surface and then exit.

[0076] Reference Figure 2 and Figure 3 In some examples of this application, refer to Figure 3 The transition element 310 includes at least one freeform prism 313. The freeform prism 313 includes at least a first optical surface 314 near the homogenizing element 200 and a second optical surface 315 near the DMD 320. Both the first optical surface 314 and the second optical surface 315 are freeform surfaces.

[0077] Please continue to refer to Figure 3 In embodiments of this application, the transition element 310 may also be at least one freeform prism 313, wherein the freeform prism 313 includes a first optical surface 314 near the light-diffusing element 200, that is... Figure 3 The lower surface of the freeform prism 313 is shown in the diagram. The freeform prism 313 also includes a second optical surface 315 near the DMD 320, namely... Figure 3 The upper surface of the freeform prism 313 is shown in the figure.

[0078] It should be noted that in the embodiments of this application, the freeform prism 313 may include, but is not limited to, only one; that is, multiple freeform prisms may also be provided. This application does not limit the number of freeform prisms 313. However, increasing the number of freeform prisms 313 may increase the size of the optical module. Therefore, the number of freeform prisms 313 should be reasonably adjusted according to the imaging requirements.

[0079] The optical module in this application embodiment refers to... Figure 3 The path of light propagation is as follows:

[0080] In the overall optical path, the incident light directly enters the recess 110, which expands the incident light beam before it propagates to the second surface 102. The second surface 102 performs total internal reflection on all the expanded light beams to collimate them into parallel light beams. The parallel light beams are reflected by the third surface 103 and then enter the homogenizing element 200. After being homogenized by the homogenizing element 200, the light beams exiting the homogenizing element propagate to the deflection and reflection assembly 300. The deflection and reflection assembly 300 includes a freeform prism 313. The light beams exiting the homogenizing element 200 pass through the second optical surface 315 of the freeform prism 313 and enter the DMD 320. The light beams reflected by the DMD 320 enter the first optical surface 314 of the freeform prism 313 and exit after total internal reflection at the first optical surface 314.

[0081] In some examples of this application, the light-diffusing element 200 is a multi-lens spectacle lens, which is composed of an array of multiple lens units, and the lens units are in the shape of regular hexagons.

[0082] Specifically, the smallest unit of a compound lens is a regular hexagonal lens. Please refer to [link / reference needed]. Figure 4 The distance between the centers of two adjacent regular hexagonal lenses in the same horizontal row is A, and the distance between the centers of adjacent regular hexagonal lenses in the same vertical row is... In this embodiment of the application, A = B, and at this time, the smallest constituent unit of the compound eyeglass lens is a Hokler hexagonal unit matrix.

[0083] The third surface 103 of the collimating and deflecting prism 100 reflects the combined light beam into the homogenizing element 200. The homogenizing element 200 transforms the light reflected by the third surface 103 into light with uniform intensity for emission, thereby improving the uniformity of the light beam.

[0084] In some examples of this application, a reflective film is provided on the third surface 103 of the collimating deflection prism 100.

[0085] By providing a reflective film on the third surface 103, it is possible to reflect parallel light rays collimated by the second surface 102 without restricting the surface shape of the third surface 103, so that the light rays can enter the light homogenizing element 200. In addition, the third surface 103 and the second surface 102 cooperate to achieve the convergence and beaming of light rays of different colors.

[0086] It should be noted that the third surface 103 can be set as a spherical surface or an aspherical surface. This application does not limit the surface shape of the third surface 103, which simplifies the structural design of the optical module.

[0087] The reflective film can be applied to the third surface 103 by electroplating or by adhesive bonding.

[0088] The third surface 103 reflects light by setting a reflective film, which is easy to process, has low cost, and has a good reflection effect.

[0089] This application also provides a projection device, including the optical module described above. For example, the projection device can be a DLP projection device.

[0090] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. An optical module characterized by comprising: The collimating and turning prism comprises a collimating and turning prism (100) comprising at least a first surface (101), a second surface (102) and a third surface (103), wherein a recess (110) is formed on at least a partial area of the first surface (101); The recess (110) is used for receiving incident light and propagating the expanded beam to the second surface (102), the second surface (102) is used for totally reflecting all the light to collimate the light into parallel light, and the third surface (103) cooperates with the second surface (102) to converge the collimated parallel light, which can be reflected on the third surface (103) and then emitted; The light uniformization element (200) and the turning reflection assembly (300); wherein the light uniformization element (200) is located between the collimating and turning prism (100) and the turning reflection assembly (300); The first surface (101) is located on the light-in side, and the incident light is incident into the recess (110); The light uniformization element (200) is arranged close to the second surface (102); The light reflected on the third surface (103) is incident into the light uniformization element (200), and the light emitted after the uniformization treatment is propagated to the turning reflection assembly (300), and the light emitted by the turning reflection assembly (300) is projected and imaged on the imaging surface.

2. The optical module according to claim 1, wherein The recess (110) is a spherical surface or a non-spherical surface structure.

3. The optical module according to claim 1, wherein The second surface (102) is a free curved surface or an even non-spherical surface.

4. The optical module according to claim 1, wherein The third surface (103) is a Fresnel surface.

5. The optical module according to claim 1, wherein The turning reflection assembly (300) comprises a turning element (310) and a DMD (320); wherein the turning element (310) is located between the light uniformization element (200) and the DMD (320).

6. The optical module according to claim 5, wherein The turning element (310) comprises a second prism (311) and a third prism (312), and the two surfaces of the second prism (311) and the third prism (312) are glued to form a glued prism group.

7. The optical module according to claim 5, wherein The turning element (310) comprises at least one free curved surface prism (313), which comprises at least a first optical surface (314) close to the light uniformization element (200) and a second optical surface (315) close to the DMD (320), and the first optical surface (314) and the second optical surface (315) are both free curved surfaces.

8. The optical module of claim 1, wherein The light uniformization element (200) is a compound eye lens, which is composed of a plurality of lens unit arrays, wherein each lens unit is a regular hexagon.

9. The optical module of claim 1, wherein The third surface (103) is provided with a reflective film.

10. A projection apparatus, characterized by, The optical module comprises the light uniformization element (200) and the turning reflection assembly (300).

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