Projection lens and projection device

Abstract

A projection lens comprises a first optical lens group and a second optical lens group. The first optical lens group is used for transmitting the image light beam to the second optical lens group. The second optical lens group is used for projecting the image light beam out of the projection lens. The second optical lens group comprises a first reflecting element, a second reflecting element and an optical element. The optical member is disposed between the first and second reflective elements. The optical part comprises a light-transmitting area and a reflecting area. The first reflecting element is used for reflecting the image light beam from the first optical lens group and transmitting the image light beam to the light-transmitting area. The light-transmitting area is used for allowing the image light beam from the first reflecting element to pass through and be transmitted to the second reflecting element. The second reflecting element is used for reflecting the image light beam from the light-transmitting area and transmitting the image light beam to the reflecting area. The reflecting area is used for reflecting the image light beam from the second reflecting element. The invention further provides a projection device with the projection lens. According to the projection lens and the projection device, the light path can be folded to reduce the size of the projection lens, the manufacturing difficulty of the projection lens can be simplified, and meanwhile good optical quality is maintained.

Description

Technical Field

[0001] The invention relates to an optical lens and an electronic device, and in particular to a projection lens and a projection device. Background Art

[0002] The current trend of projectors is to develop high brightness and large-size projection screens. Therefore, all manufacturers focus on designing a suitable wide-angle lens structure to reduce its weight and volume and effectively reduce production costs. Under these various considerations, wide-angle lens designs are mostly based on fixed-focus lenses. Generally speaking, in order to reduce the size of the lens, wide-angle lenses usually form an intermediate image in the design of the optical path to reduce the overall optical path, which can further reduce the outer diameter of the overall lens. An optical system that forms an intermediate image will have an overall length greater than an optical design without an intermediate image.

[0003] However, in the current technology, the number of lenses in the lens is too large, so it has no advantage in price and market competition. In addition, if the design length of the lens is too long, it is easy to affect the volume of the projector. Therefore, the design of a lens that can reduce production costs and shorten the assembly process time is what the field needs to focus on.

[0004] The "background technology" section is only used to help understand the content of the present invention. Therefore, the content disclosed in the "background technology" section may contain some known technologies that are not known to those skilled in the art. The content disclosed in the "background technology" section does not mean that the content or the problems to be solved by one or more embodiments of the present invention have been known or recognized by those skilled in the art before the application of the present invention. Summary of the invention

[0005] The invention provides a projection lens and a projection device, which can fold the optical path to reduce the volume of the projection lens, simplify the manufacturing difficulty of the projection lens, and maintain good optical quality.

[0006] Other purposes and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

[0007] To achieve one or part or all of the above purposes or other purposes, the present invention provides a projection lens, including a first optical lens group and a second optical lens group. The first optical lens group is used to transmit an image beam to the second optical lens group. The second optical lens group is used to project the image beam out of the projection lens. The second optical lens group includes a first reflective element, a second reflective element and an optical member. The optical member is disposed between the first reflective element and the second reflective element. The optical member includes a light-transmitting area and a reflection area. The first reflective element is used to reflect the image beam from the first optical lens group and transmit it to the light-transmitting area. The light-transmitting area is used to allow the image beam from the first reflective element to pass through and be transmitted to the second reflective element. The second reflective element is used to reflect the image beam from the light-transmitting area and transmit it to the reflection area. The reflection area is used to reflect the image beam from the second reflective element.

[0008] To achieve one or part or all of the above purposes or other purposes, the present invention further provides a projection device, including an illumination system, at least one light valve and a projection lens. The illumination system is used to provide an illumination beam. At least one light valve is arranged on the transmission path of the illumination beam to convert the illumination beam into an image beam. The projection lens is arranged on the transmission path of the image beam. The projection lens includes a first optical lens group and a second optical lens group. The first optical lens group is used to transmit the image beam to the second optical lens group. The second optical lens group is used to project the image beam out of the projection lens. The second optical lens group includes a first reflective element, a second reflective element and an optical member. The optical member is arranged between the first reflective element and the second reflective element. The optical member includes a light-transmitting area and a reflection area. The first reflective element is used to reflect the image beam from the first optical lens group and transmit it to the light-transmitting area. The light-transmitting area is used to allow the image beam from the first reflective element to pass through and be transmitted to the second reflective element. The second reflective element is used to reflect the image beam from the light-transmitting area and transmit it to the reflection area. The reflection area is used to reflect the image beam from the second reflective element.

[0009] Based on the above, the embodiments of the present invention have at least one of the following advantages or effects. In the projection lens and the projection device of the present invention, the projection lens includes a first optical lens group and a second optical lens group, the second optical lens group includes a first reflective element, a second reflective element and an optical member, and the optical member includes a light-transmitting area and a reflective area. The light-transmitting area is used to allow the image beam from the first reflective element to pass through and be transmitted to the second reflective element, and the reflective area is used to reflect the image beam from the second reflective element. Therefore, when the image beam is transmitted from the first optical lens group to the second optical lens group, the image beam is transmitted to the first reflective element to generate a first reflection, transmitted through the light-transmitting area and transmitted to the second reflective element to generate a second reflection, and transmitted to the reflective area to generate a third reflection. In this way, the optical path can be folded to reduce the volume of the projection lens, and the manufacturing difficulty of the projection lens can be simplified while maintaining good optical quality. In addition, when the image beam passes through the light-transmitting area, the distortion aberration can be effectively reduced, the distance between the first reflective element and the second reflective element can be reduced, the optical resolution can be improved, and the effective diameter of the second reflective element can be reduced.

[0010] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below with reference to the accompanying drawings for detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 FIG. 4 is a schematic diagram of a projection device according to an embodiment of the present invention.

[0012] Figure 2 FIG. 4 is a schematic diagram of a projection lens according to an embodiment of the present invention.

[0013] Figure 3 for Figure 2 Modulation transfer function diagram of the projection lens.

[0014] Figure 4A and Figure 4B They are Figure 2 Field curvature aberration diagram of the projection lens in different directions.

[0015] Figure 5 for Figure 2 Distortion diagram of the projection lens.

[0016] Figures 6A to 6V for Figure 2 Beam fan diagram of the projection lens.

[0017] Description of reference numerals:

[0018] 10: Projection device

[0019] 50: Lighting system

[0020] 60: Light valve

[0021] 100: Projection lens

[0022] 110: First optical unit

[0023] 120: Second optical unit

[0024] 122: First reflective element

[0025] 124: Second reflective element

[0026] 126: Optics

[0027] A1, A2: Optical axis

[0028] B1: light-transmitting area

[0029] B2: Reflection area

[0030] C: Angle

[0031] D1: Anti-reflective coating

[0032] D2: Reflective coating

[0033] L1: First lens

[0034] L2: Second lens

[0035] L3: The third lens

[0036] L4: The fourth lens

[0037] L5: The fifth lens

[0038] L6: The sixth lens

[0039] L7: Seventh lens

[0040] L8: The eighth lens

[0041] L9: The ninth lens

[0042] L10: The tenth lens

[0043] L11: Eleventh lens

[0044] L12: Twelfth lens

[0045] L13: Thirteenth lens

[0046] L14: Fourteenth lens

[0047] LB: Lighting beam

[0048] LI: Image beam

[0049] ST: Aperture. DETAILED DESCRIPTION

[0050] The above-mentioned other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only the directions with reference to the accompanying drawings. Therefore, the directional terms used are used to illustrate and not to limit the present invention.

[0051] Figure 1 This is a schematic diagram of a projection device according to an embodiment of the present invention. Figure 1 The present embodiment provides a projection device 10, comprising an illumination system 50, at least one light valve 60 and a projection lens 100. The illumination system 50 is used to provide an illumination beam LB. The at least one light valve 60 is disposed on the transmission path of the illumination beam LB to convert the illumination beam LB into an image beam LI. The projection lens 100 is disposed on the transmission path of the image beam LI and is used to project the image beam LI out of the projection device 10 to a projection target (not shown), such as a screen or a wall.

[0052] The illumination system 50 is used to provide an illumination beam LB. For example, in the present embodiment, the illumination system 50 is composed of a plurality of light emitting elements, a wavelength conversion element, a light homogenizing element, a filter element, and a plurality of light splitting and combining elements, and is used to provide light of different wavelengths to form an illumination beam LB. The plurality of light emitting elements are, for example, light emitting diodes (LED) or laser diodes (LD). However, the present invention does not limit the type or form of the illumination system 50 in the projection device 10, and its detailed structure and implementation can be sufficiently taught, suggested, and implemented by the common knowledge in the relevant technical field, and therefore will not be described in detail.

[0053] The light valve 60 is, for example, a reflective light modulator such as a Liquid Crystal On Silicon panel (LCoS panel) or a Digital Micro-mirror Device (DMD). In some embodiments, the light valve 60 may also be a transmissive light modulator such as a Transparent Liquid Crystal Panel, an Electro-Optical Modulator, a Magneto-Optic modulator, or an Acousto-Optic Modulator (AOM). The present invention does not limit the type and kind of the light valve 60. The detailed steps and implementation methods of the method of converting the illumination light beam LB into the image light beam LI by the light valve 60 can be sufficiently taught, suggested, and implemented by the common knowledge in the relevant technical field, and therefore will not be repeated. In different embodiments, the number of the light valve 60 can be designed to be one to three, and the present invention is not limited thereto.

[0054] Figure 2 FIG. 1 is a schematic diagram of a projection lens according to an embodiment of the present invention. The projection lens 100 shown in this embodiment can be applied to at least Figure 1 The projection lens 100 shown in FIG. 1 is used as an example in the following description. Figure 1 and Figure 2 The projection lens 100 includes a first optical lens group 110 and a second optical lens group 120 . The first optical lens group 110 is used to transmit the image beam LI to the second optical lens group 120 , and the second optical lens group 120 is used to project the image beam LI out of the projection lens 100 .

[0055] The first optical lens group 110, for example, includes a combination of one or more optical lenses with refractive power, for example, various combinations of non-planar lenses such as biconcave lenses, biconvex lenses, concave-convex lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses. The present invention does not limit the type and type of the first optical lens group 110. For example, in this embodiment, the first optical lens group 110 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an aperture ST, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, a thirteenth lens L13, and a fourteenth lens L14 in order from the image side to the object side along the optical axis A1.

[0056] The second optical lens group 120 includes a first reflective element 122, a second reflective element 124, and an optical element 126. The optical element 126 is disposed between the first reflective element 122 and the second reflective element 124. The optical element 126 includes a light-transmitting area B1 and a reflective area B2. The light-transmitting area B1 is located between the reflective area B2 and the first optical lens group 110. The first reflective element 122 is used to reflect the image beam LI from the first optical lens group 110 and transmit it to the light-transmitting area B1. In this embodiment, the first reflective element 122 is, for example, a plane mirror, but in other embodiments, the first reflective element 122 may also be a concave mirror, and the present invention is not limited thereto. The second reflective element 124 is used to reflect the image beam LI from the light-transmitting area B1 of the optical element 126 and transmit it to the reflective area B2. In this embodiment, the second reflective element 124 is, for example, a concave mirror, but the present invention is not limited thereto.

[0057] The light-transmitting area B1 of the optical element 126 is used to allow the image beam LI from the first reflective element 122 to pass through and be transmitted to the second reflective element 124, and the reflective area B2 is used to reflect the image beam LI from the second reflective element 124. In other words, the optical element 126 has two areas with different optical effects. For example, in this embodiment, the optical element 126 has an optical axis A2, and the boundary between the light-transmitting area B1 and the reflective area B2 is located at the optical axis A2, and the optical axis A1 of the first optical lens group 110 and the optical axis A2 of the optical element 126 have an angle C, such as 90 degrees, that is, the optical axis A1 of the first optical lens group 110 is perpendicular to the optical axis A2 of the optical element 126, but the present invention is not limited thereto. Specifically, the optical element 126 is an optical lens with refractive power, such as various combinations of non-planar lenses such as biconcave lenses, biconvex lenses, concave-convex lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses, and its surface is, for example, a spherical surface or an aspherical surface. Therefore, when the image beam LI passes through the light-transmitting area B1, the distortion aberration can be effectively reduced, the distance between the first reflective element 122 and the second reflective element 124 can be reduced, the optical resolution can be improved, and the effective diameter of the second reflective element 124 can be reduced. In this embodiment, the optical element 126 includes an anti-reflection coating D1 and a reflective coating D2, the anti-reflection coating D1 is disposed in the light-transmitting area B1, and the reflective coating D2 is disposed in the reflective area B2. In one embodiment, the light-transmitting area B1 of the optical element 126 may not have the anti-reflection coating D1, and the reflective coating D2 is only disposed in the reflective area B2. Therefore, when the image beam LI is transmitted from the first optical lens group 110 to the second optical lens group 120, the image beam LI is transmitted to the first reflective element 122 to generate a first reflection, transmitted through the light-transmitting area B1 and transmitted to the second reflective element 124 to generate a second reflection, and transmitted to the reflective area B2 to generate a third reflection. In this way, the optical path can be folded to reduce the volume of the projection lens 100 , and the manufacturing difficulty of the projection lens 100 can be simplified while maintaining good optical quality.

[0058] In this embodiment, the actual design of each element of the first optical lens group 110 and the second optical lens group 120 can be seen in the following Table 1. In Table 1, the reflection area B2 to the fourteenth lens L14 have a surface R1 and a surface R2, or only a surface R1, from the image side to the object side, and the "distance" refers to the straight-line distance between a surface and the next adjacent surface on the optical axis A1 or the optical axis A2. For example, the distance of the surface R1 of the first lens L1 refers to the distance between the surface R1 of the first lens L1 and the surface R2 of the first lens L1 on the optical axis A1, and the distance of the surface R2 of the first lens L1 refers to the straight-line distance between the surface R2 of the first lens L1 and the surface R1 of the second lens L2 on the optical axis A1, and so on.

[0059] Table 1

[0060]

[0061]

[0062] Figure 3 for Figure 2 The modulation transfer function diagram of the projection lens. Please refer to Figure 3 In this embodiment, the second reflective element 124, the surface R1 of the first lens L1, the surface R2 of the first lens L1, the surface R1 of the seventh lens L7, the surface R2 of the seventh lens L7, the surface R1 of the fourteenth lens L14, and the surface R2 of the fourteenth lens L14 are aspherical surfaces, and the surfaces of the remaining lenses are spherical surfaces. The formula of the aspherical surface can be shown as follows:

[0063]

[0064] In the above formula, X is the offset (sag) in the direction of the optical axis. c' is the reciprocal of the radius of the osculating sphere, that is, the reciprocal of the radius of curvature close to the optical axis. K is the quadratic surface coefficient. y is the aspheric height, that is, the height from the center of the lens to the edge of the lens. AG represent the aspheric coefficients of each order of the aspheric polynomial. Table 2 lists the parameter values ​​of the aspheric surface in this embodiment.

[0065] Table 2

[0066]

[0067]

[0068] Figure 3 for Figure 2 The modulation transfer function of the projection lens is shown in Figure 2. Figure 3 . Figure 3The figure is a modulation transfer function (MTF) diagram of the projection lens 100 at different image heights, wherein the horizontal axis is the focus shift, the vertical axis is the modulus of the optical transfer function, T represents the curve in the meridian direction, S represents the curve in the sagittal direction, and the value next to "TS" represents the image height. It can be verified that the optical transfer function curve displayed by the projection lens 100 of this embodiment is within the standard range, so it has good optical imaging quality, such as Figure 3 as displayed.

[0069] Figure 4A and Figure 4B They are Figure 2 The field curvature aberration diagram of the projection lens in different directions. Please refer to Figure 4A and Figure 4B . Figure 4A and Figure 4B The diagrams respectively illustrate Figure 2 In the embodiment, when the wavelength is 0.465 μm (micrometer), 0.525 μm (micrometer) and 0.638 μm (micrometer), the field curvature aberration in the sagittal direction and the field curvature aberration in the tangential direction on the imaging surface, the focal length variation of the three representative wavelengths in the entire field of view falls within ±0.05 mm, indicating that the optical system of the embodiment can effectively eliminate aberrations.

[0070] Figure 5 for Figure 2 Distortion diagram of the projection lens. Please refer to Figure 5 . Figure 5 Diagrammatic description of Figure 2 Example: Distortion Aberration on the imaging surface when the wavelength is 0.465μm, 0.525μm and 0.638μm. Figure 5 The distortion aberration diagram shows that the distortion aberration of this embodiment can be maintained within the range of ±0.5%, indicating that the distortion aberration of this embodiment meets the imaging quality requirements of the optical system.

[0071] Figures 6A to 6V for Figure 2 The beam fan diagram of the projection lens. Please refer to Figures 6A to 6V . Figures 6A to 6V 1 is a ray fan plot of the projection lens 100 at different image heights, wherein the maximum scale and the minimum scale of the ex, ey, Px and Py axes are +10 microns and -10 microns respectively. Figures 6A to 6VThe displayed graphics are all within the standard range, which verifies that the projection lens 100 of this embodiment can achieve good optical imaging quality.

[0072] In summary, in the projection lens and the projection device of the present invention, the projection lens includes a first optical lens group and a second optical lens group, the second optical lens group includes a first reflective element, a second reflective element and an optical member, and the optical member includes a light-transmitting area and a reflective area. The light-transmitting area is used to allow the image beam from the first reflective element to pass through and be transmitted to the second reflective element, and the reflective area is used to reflect the image beam from the second reflective element. Therefore, when the image beam is transmitted from the first optical lens group to the second optical lens group, the image beam is transmitted to the first reflective element to generate a first reflection, transmitted through the light-transmitting area and transmitted to the second reflective element to generate a second reflection, and transmitted to the reflective area to generate a third reflection. In this way, the optical path can be folded to reduce the volume of the projection lens, and the manufacturing difficulty of the projection lens can be simplified while maintaining good optical quality. In addition, when the image beam passes through the light-transmitting area, the distortion aberration can be effectively reduced, the distance between the first reflective element and the second reflective element can be reduced, the optical resolution can be improved, and the effective diameter of the second reflective element can be reduced.

[0073] However, the above is only a preferred embodiment of the present invention, and it cannot be used to limit the scope of the implementation of the present invention. That is, all simple equivalent changes and modifications made according to the claims and the content of the invention of the present invention are still within the scope of the patent of the present invention. In addition, any embodiment or claim of the present invention does not need to achieve all the purposes, advantages or features disclosed by the present invention. In addition, the abstract and title (invention name) are only used to assist in the retrieval of patent documents, and are not used to limit the scope of rights of the present invention. In addition, the terms "first", "second", etc. mentioned in this specification or claims are only used to name the name of the element or distinguish different embodiments or scopes, and are not used to limit the upper or lower limit on the number of elements.

Claims

1. A projection lens, characterized in that: The projection lens comprises a first optical lens group and a second optical lens group, wherein: The first optical lens group is used to transmit the image beam to the second optical lens group; and The second optical lens group is used to project the image beam out of the projection lens. The second optical lens group includes a first reflective element, a second reflective element, and an optical member. The optical member is disposed between the first reflective element and the second reflective element. The optical member includes a light-transmitting area and a reflective area, wherein: The first reflective element is used to reflect the image light beam from the first optical lens group and transmit it to the light-transmitting area; The light-transmitting area is used to allow the image light beam from the first reflective element to pass through and be transmitted to the second reflective element; The second reflective element is used to reflect the image light beam from the light-transmitting area and transmit it to the reflective area; and The reflection area is used to reflect the image light beam from the second reflection element.

2. The projection lens according to claim 1, characterized in that: The optical element has an optical axis, and a boundary line between the light-transmitting area and the reflective area is located on the optical axis.

3. The projection lens according to claim 2, characterized in that: The first optical lens group has an optical axis, and the optical axis of the first optical lens group and the optical axis of the optical component form an included angle.

4. The projection lens according to claim 1, characterized in that: The light-transmitting area is located between the reflective area and the first optical lens group.

5. The projection lens according to claim 1, wherein: The optical component includes a reflective coating, and the reflective coating is configured in the reflective area.

6. The projection lens according to claim 1, wherein: The optical element includes an anti-reflection coating, and the anti-reflection coating is configured in the light-transmitting area.

7. The projection lens according to claim 1, wherein: The optical component is an optical lens with refractive power.

8. The projection lens according to claim 1, wherein: The surface of the optical component is a spherical surface or an aspherical surface.

9. The projection lens according to claim 1, wherein: The first reflecting element is a plane mirror or a concave mirror.

10. The projection lens according to claim 1, wherein: The second reflecting element is a concave mirror.

11. A projection device, characterized in that: The projection device comprises an illumination system, at least one light valve and a projection lens, wherein: The lighting system is used to provide a lighting beam; The at least one light valve is disposed on the transmission path of the illumination light beam, and is used to convert the illumination light beam into an image light beam; and The projection lens is disposed on the transmission path of the image light beam, and the projection lens includes a first optical lens group and a second optical lens group, wherein: The first optical lens group is used to transmit the image beam to the second optical lens group; and The second optical lens group is used to project the image beam out of the projection lens. The second optical lens group includes a first reflective element, a second reflective element, and an optical member. The optical member is disposed between the first reflective element and the second reflective element. The optical member includes a light-transmitting area and a reflective area, wherein: The first reflective element is used to reflect the image light beam from the first optical lens group and transmit it to the light-transmitting area; The light-transmitting area is used to allow the image light beam from the first reflective element to pass through and be transmitted to the second reflective element; The second reflective element is used to reflect the image light beam from the light-transmitting area and transmit it to the reflective area; and The reflection area is used to reflect the image light beam from the second reflection element.

12. The projection device according to claim 11, characterized in that: The optical element has an optical axis, and a boundary line between the light-transmitting area and the reflective area is located on the optical axis.

13. The projection device according to claim 12, characterized in that: The first optical lens group has an optical axis, and the optical axis of the first optical lens group and the optical axis of the optical component form an included angle.

14. The projection device according to claim 11, characterized in that: The light-transmitting area is located between the reflective area and the first optical lens group.

15. The projection device according to claim 11, characterized in that: The optical component includes a reflective coating, and the reflective coating is configured in the reflective area.

16. The projection device according to claim 11, characterized in that: The optical element includes an anti-reflection coating, and the anti-reflection coating is configured in the light-transmitting area.

17. The projection device according to claim 11, characterized in that: The optical component is an optical lens with refractive power.

18. The projection device according to claim 11, characterized in that: The surface of the optical component is a spherical surface or an aspherical surface.

19. The projection device according to claim 11, characterized in that: The first reflecting element is a plane mirror or a concave mirror.

20. The projection device according to claim 11, characterized in that: The second reflecting element is a concave mirror.

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