Projection lens and projection device

Abstract

A projection lens includes a first optical lens group and a second optical lens group. The first optical lens group transmits an image beam to the second optical lens group. The second optical lens group projects the image beam out of the projection lens. The second optical lens group includes first and second reflective elements and an optical component. The optical component is disposed between the first and second reflective elements. The optical component includes a light-transmitting area and a reflective area. The first reflective element reflects the image beam from the first optical lens group and transmits it to the light-transmitting area. The light-transmitting area allows the image beam from the first reflective element to pass through and be transmitted to the second reflective element. The second reflective element reflects the image beam from the light-transmitting area and transmits it to the reflective area. The reflective area reflects the image beam from the second reflective element. A projection device equipped with the projection lens is also provided. The projection lens and projection device of the present invention have a foldable optical path to reduce the size of the projection lens, simplifying the manufacturing difficulty of the projection lens while maintaining good optical quality.

Description

Technical Field

[0001] This invention relates to an optical lens and an electronic device, and more particularly to a projection lens and a projection device. Background Technology

[0002] The current trend in projectors is towards high brightness and large projection screens. Therefore, manufacturers are focusing on designing suitable wide-angle lens architectures to reduce weight and size while effectively lowering manufacturing costs. Considering these factors, wide-angle lens designs mostly utilize fixed-focus lenses. Generally, to reduce lens size, wide-angle lenses typically incorporate an intermediate image in their optical path design, thus narrowing the overall optical path and further reducing the overall lens diameter. An optical system that forms an intermediate image will have a longer overall length than an optical design without an intermediate image.

[0003] However, current technology results in lenses with an excessive number of elements, making them less competitive in terms of price and market share. Furthermore, excessively long lenses can negatively impact the size of the projector. Therefore, designing lenses that reduce production costs and shorten assembly time is a crucial area of ​​focus in this field.

[0004] The "Background Art" paragraph is only used to help understand the content of this invention. Therefore, the content disclosed in the "Background Art" paragraph may include some known technologies that are not known to those skilled in the art. The content disclosed in the "Background Art" paragraph does not mean that the content or the problems to be solved by one or more embodiments of this invention were known or understood by those skilled in the art prior to this application. Summary of the Invention

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

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

[0007] To achieve one or more of the above-mentioned objectives, or other objectives, 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 element. The optical element is disposed between the first reflective element and the second reflective element. The optical element includes a light-transmitting area and a reflective 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 allows 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 reflective area. The reflective area is used to reflect the image beam from the second reflective element.

[0008] To achieve one or more of the above-mentioned objectives, or other objectives, the present invention further provides a projection device, including an illumination system, at least one light valve, and a projection lens. The illumination system provides an illumination beam. At least one light valve is disposed in the transmission path of the illumination beam to convert the illumination beam into an image beam. The projection lens is disposed in 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 transmits the image beam to the second optical lens group. The second optical lens group projects 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 element. The optical element is disposed between the first reflective element and the second reflective element. The optical element includes a light-transmitting area and a reflective area. The first reflective element reflects the image beam from the first optical lens group and transmits it to the light-transmitting area. The light-transmitting area allows the image beam from the first reflective element to pass through and be transmitted to the second reflective element. The second reflective element reflects the image beam from the light-transmitting area and transmits it to the reflective area. The reflective area reflects 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 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 component. The optical component includes a light-transmitting area and a reflective area. The light-transmitting area allows the image beam from the first reflective element to pass through and be transmitted to the second reflective element, while the reflective area reflects 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 reflected for the first time by the first reflective element, reflected a second time by the second reflective element after passing through the light-transmitting area, and reflected a third time by the reflective area. This allows for a foldable optical path to reduce the size of the projection lens and simplifies its manufacturing process while maintaining good optical quality. Furthermore, when the image beam passes through the light-transmitting area, distortion aberrations are effectively reduced, the distance between the first and second reflective elements is reduced, optical resolution is improved, and the effective diameter of the second reflective element is reduced.

[0010] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

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

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

[0013] Figure 3 for Figure 2 The modulation conversion function diagram of the projection lens.

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

[0015] Figure 5 for Figure 2 The distortion and aberration diagram of the projection lens.

[0016] Figures 6A to 6V for Figure 2 The beam pattern of the projection lens.

[0017] Explanation of reference numerals in the attached figures:

[0018] 10: Projection device

[0019] 50: Lighting System

[0020] 60: Light valve

[0021] 100: Projection lens

[0022] 110: First optical lens group

[0023] 120: Second optical lens group

[0024] 122: First reflecting element

[0025] 124: Second reflective element

[0026] 126: Optical components

[0027] A1, A2: Optical axis

[0028] B1: Translucent Area

[0029] B2: Reflection Zone

[0030] C: included angle

[0031] D1: Anti-reflective coating

[0032] D2: Reflective coating

[0033] L1: First lens

[0034] L2: Second lens

[0035] L3: Third lens

[0036] L4: Fourth Lens

[0037] L5: Fifth Lens

[0038] L6: Sixth Lens

[0039] L7: Seventh Lens

[0040] L8: Eighth Lens

[0041] L9: Ninth Lens

[0042] L10: Tenth Lens

[0043] L11: Eleventh Lens

[0044] L12: The twelfth lens

[0045] L13: The Thirteenth Lens

[0046] L14: The Fourteenth Lens

[0047] LB: Illumination beam

[0048] LI: Image Beam

[0049] ST: Aperture. Detailed Implementation

[0050] The foregoing descriptions and other technical contents, features, and effects of this invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms used in the following embodiments, such as up, down, left, right, front, or back, are merely for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0051] Figure 1 This is a schematic diagram of a projection device according to an embodiment of the present invention. Please refer to... Figure 1 This embodiment provides a projection device 10, including an illumination system 50, at least one light valve 60, and a projection lens 100. The illumination system 50 provides an illumination beam LB. The at least one light valve 60 is disposed in 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 in the transmission path of the image beam LI and projects the image beam LI from the projection device 10 onto a projection target (not shown), such as a screen or wall.

[0052] The lighting system 50 is used to provide an illumination beam LB. For example, in this embodiment, the lighting system 50 is composed of a combination of multiple light-emitting elements, wavelength conversion elements, light-diffusing elements, light-filtering elements, and multiple light-splitting and combining elements to provide light of different wavelengths to form the illumination beam LB. The multiple light-emitting elements are, for example, light-emitting diodes (LEDs) or laser diodes (LDs). However, the present invention does not limit the type or form of the lighting system 50 in the projection device 10. Its detailed structure and implementation can be sufficiently taught, suggested, and described by knowledge of ordinary knowledge in the art, and therefore will not be elaborated further.

[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 micromirror 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-optic modulator, a magneto-optic modulator, or an acousto-optic modulator (AOM). This invention does not limit the type or form of the light valve 60. The detailed steps and implementation of the method by which the light valve 60 converts the illumination beam LB into the image beam LI are sufficiently taught, suggested, and illustrated by knowledge of the art and will not be elaborated further. In different embodiments, the number of light valves 60 may be designed to be one to three, and this invention is not limited thereto.

[0054] Figure 2 This 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 is shown. Therefore, the following explanation uses this as an example. Please refer to it. 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 L1 to the second optical lens group 120, and the second optical lens group 120 is used to project the image beam L1 out of the projection lens 100.

[0055] The first optical lens group 110 includes, for example, a combination of one or more optical lenses 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. The present invention does not limit the type or form of the first optical lens group 110. For example, in this embodiment, the first optical lens group 110 includes, along the optical axis A1 from the image side to the object side, 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.

[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, and 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 reflects the image beam L1 from the first optical lens group 110 and transmits it to the light-transmitting area B1. In this embodiment, the first reflective element 122 is, for example, a plane mirror; however, in other embodiments, the first reflective element 122 may also be a concave mirror, and the invention is not limited thereto. The second reflective element 124 reflects the image beam L1 from the light-transmitting area B1 of the optical element 126 and transmits it to the reflective area B2. In this embodiment, the second reflective element 124 is, for example, a concave mirror, but the invention is not limited thereto.

[0057] The light-transmitting area B1 of the optical element 126 allows the image beam L1 from the first reflecting element 122 to pass through and be transmitted to the second reflecting element 124, while the reflecting area B2 reflects the image beam L1 from the second reflecting 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, the boundary between the light-transmitting area B1 and the reflecting area B2 is located on 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, for example, 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 including biconcave lenses, biconvex lenses, concave-convex lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses, and its surface is, for example, spherical or aspherical. Therefore, when the image beam LI passes through the light-transmitting area B1, it can effectively reduce distortion aberrations, reduce the distance between the first reflective element 122 and the second reflective element 124, improve optical resolution, and reduce the effective diameter of the second reflective element 124. In this embodiment, the optical component 126 includes an anti-reflective coating D1 and a reflective coating D2. The anti-reflective 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 component 126 may not have the anti-reflective coating D1, and the reflective coating D2 may only be 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 and generates a first reflection, transmitted through the light-transmitting area B1 and transmitted to the second reflective element 124 and generates a second reflection, and transmitted to the reflective area B2 and generates a third reflection. In this way, the optical path can be folded to reduce the size of the projection lens 100 and simplify the manufacturing process of the projection lens 100 while maintaining good optical quality.

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

[0059] Table 1

[0060]

[0061]

[0062] Figure 3 for Figure 2 The modulation conversion function graph of the projection lens. Please refer to... Figure 3 In this embodiment, the surfaces R1 and R2 of the second reflecting element 124, the seventh lens L7, the fourteenth lens L14, and the fourteenth lens L14 are aspherical surfaces, while the surfaces of the remaining lenses are spherical surfaces. The formula for an aspherical surface is as follows:

[0063]

[0064] In the above formula, X is the offset (sag) in the optical axis direction. c' is the reciprocal of the radius of the oscillating sphere, which is the reciprocal of the radius of curvature near the optical axis. K is the quadratic coefficient, and y is the aspheric height, which is the height from the center of the lens to the edge of the lens. AG represents 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 diagram of the projection lens. Please refer to... Figure 3 . Figure 3The modulation transfer function (MTF) graphs of the projection lens 100 at different image heights are shown below. The horizontal axis represents the focus shift, and the vertical axis represents the modulus of the optical transfer function. T represents the curve in the meridional direction, S represents the curve in the sagittal direction, and the value next to "TS" represents the image height. This verifies that the optical transfer function curve displayed by the projection lens 100 in this embodiment is within the standard range, thus exhibiting good optical imaging quality. Figure 3 As shown.

[0069] Figure 4A and Figure 4B They are respectively Figure 2 Field curvature aberration diagrams of the projection lens in different directions. Please refer to... Figure 4A and Figure 4B . Figure 4A and Figure 4B The diagrams are explained respectively. Figure 2 In the embodiment, when the wavelengths are 0.465 μm, 0.525 μm, and 0.638 μm, the field curvature aberrations in the sagittal and tangential directions on the imaging plane are within ±0.05 mm across the entire field of view for the three representative wavelengths. This demonstrates that the optical system of this embodiment can effectively eliminate aberrations.

[0070] Figure 5 for Figure 2 The distortion and aberration diagram of the projection lens. Please refer to... Figure 5 . Figure 5 Diagrammatic Explanation Figure 2 Examples show the distortion aberration on the imaging plane at wavelengths of 0.465 μm, 0.525 μm, and 0.638 μm, and are determined by... 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 pattern of the projection lens. Please refer to... Figures 6A to 6V . Figures 6A to 6V The projection lens 100 is shown as a ray fan plot at different image heights, where the maximum and minimum scales of the ex, ey, Px, and Py axes are +10 micrometers and -10 micrometers, 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 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 optical components. The optical components include a light-transmitting area and a reflective area. The light-transmitting area allows the image beam from the first reflective element to pass through and be transmitted to the second reflective element, while the reflective area reflects 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 reflected for the first time upon reaching the first reflective element, reflected a second time upon passing through the light-transmitting area to the second reflective element, and reflected a third time upon reaching the reflective area. This allows for a foldable optical path to reduce the size of the projection lens and simplifies its manufacturing process while maintaining good optical quality. Furthermore, when the image beam passes through the light-transmitting area, distortion aberrations are effectively reduced, the distance between the first and second reflective elements is reduced, optical resolution is improved, and the effective diameter of the second reflective element is reduced.

[0073] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Any simple equivalent changes and modifications made in accordance with the claims and description of the invention are still within the scope of this patent. Furthermore, no embodiment or claim of the present invention needs to achieve all the objectives, advantages, or features disclosed in the invention. In addition, the abstract and title (invention title) are only used to assist in patent document retrieval and are not intended to limit the scope of the invention. Furthermore, the terms "first," "second," etc., mentioned in this specification or claims are only used to name elements or distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of elements.

Claims

1. A projection lens, characterized in that, 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 element. The optical element is disposed between the first reflective element and the second reflective element. The optical element includes a light-transmitting area and a reflective area, wherein: 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 reflective area; and The reflective area is used to reflect the image beam from the second reflective element.

2. The projection lens according to claim 1, characterized in that, The optical component has an optical axis, and the boundary 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 has an angle with the optical axis of the optical element.

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, characterized in that, The optical component includes a reflective coating disposed in the reflective region.

6. The projection lens according to claim 1, characterized in that, The optical component includes an anti-reflective coating disposed in the light-transmitting area.

7. The projection lens according to claim 1, characterized in that, The optical component is an optical lens with refractive power.

8. The projection lens according to claim 1, characterized in that, The surface of the optical component is either spherical or aspherical.

9. The projection lens according to claim 1, characterized in that, The first reflecting element is a plane mirror or a concave mirror.

10. The projection lens according to claim 1, characterized in that, The second reflective element is a concave mirror.

11. A projection device, characterized in that, The projection device includes an illumination system, at least one light valve, and a projection lens, wherein: The lighting system is used to provide a beam of light; The at least one light valve is disposed in the transmission path of the illumination beam to convert the illumination beam into an image beam; and The projection lens is positioned along the transmission path of the image 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 element. The optical element is disposed between the first reflective element and the second reflective element. The optical element includes a light-transmitting area and a reflective area, wherein: 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 reflective area; and The reflective area is used to reflect the image beam from the second reflective element.

12. The projection device according to claim 11, characterized in that, The optical component has an optical axis, and the boundary 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 has an angle with the optical axis of the optical element.

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 disposed in the reflective region.

16. The projection device according to claim 11, characterized in that, The optical component includes an anti-reflective coating disposed 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 either spherical or aspherical.

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 reflective element is a concave mirror.

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