Low-cost short-focus projection lens
By using an all-plastic aspherical mirror design and optimizing lens materials, the problems of large size and high cost of LCD projection lenses have been solved, achieving low-cost short-throw projection lens imaging effect and interchangeability, suitable for short-distance large-screen projection.
Patent Information
- Application Number
- CN202423289294.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2034-12-31
AI Technical Summary
Existing LCD projection lenses are too large, difficult and costly to manufacture, and difficult to interchange with DLP micro-projection lenses. The market demands low-cost short-throw projection lenses.
By employing an all-plastic aspherical lens design and rationally matching lens materials and focal lengths, using plastic aspherical lenses as the first and second lenses, and setting an aperture stop to control the beam, low-cost short-throw projection is achieved.
It achieves a reduction in focal length, lower cost, and improved image quality for short-throw projection lenses, making them suitable for short-distance, large-screen projection, and simplifying lens design.
Smart Images
Figure CN223565976U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the field of projection technology, specifically relates to a low -cost short -focus projection lens. BACKGROUND
[0002] With the continuous popularity of projection, the requirement of high -end projection lens on the market is higher and higher, the current market projection mainly divides DLP projection and LCD projection, DLP projection is small in size, good in color, and the commonly used is short -focus lens, and the lens has an off -axis, but the overall cost is high, the market share is low, the market share of LCD projection is high in recent years, but the size is generally larger than DLP projection, and generally is long -focus lens without off -axis (projection ratio 1.2~1.4, off -axis is 0), the number of lens in the lens is less, and the overall lens design and manufacturing are low.
[0003] Problems of prior art:
[0004] At present, due to the too large size of LCD projection, the difficulty and cost of lens element processing are very high, and due to the too large size of LCD projection lens, it is difficult to interchange with common DLP micro -projection lens, and the demand of low -cost scheme projection lens on the market is more and more intense, so it is urgent to develop a short -focus optical projection lens with cost advantage. Utility model content
[0005] The utility model aims at providing a low -cost short -focus projection lens, which can adopt the method of full plastic aspheric surface mirror, and the focal length is reduced by reasonable collocation and optimization, so that the better experience effect of projecting a large screen in a short distance is realized.
[0006] The technical scheme adopted by the utility model is as follows:
[0007] A low -cost short -focus projection lens, including first lens, second lens, fresnel mirror and LCD display screen arranged in order along the optical axis from object side to image, the first lens is a convex-concave positive focal power aspheric lens, and the second lens is a convex-convex positive focal power aspheric lens.
[0008] The material of the first lens and the second lens is plastic.
[0009] The focal length of the first lens and the second lens is positive.
[0010] The first lens and the low -cost short -focus projection lens satisfy the following relationship: 1.3<|f1 / f|<2.0, wherein f1 is the focal length of the first lens, and f is the optical system focal length of the low -cost short -focus projection lens.
[0011] The second lens and the low-cost short-focus projection lens satisfy the following relationship: 1.5 < |f2 / f| < 2.2, wherein f2 is the focal length of the second lens, and f is the optical system focal length of the low-cost short-focus lens.
[0012] The Abbe number of the first lens is less than 35, and the Abbe number of the second lens is greater than 50.
[0013] A diaphragm is further arranged between the image side surface of the first lens and the object side surface of the second lens.
[0014] The technical effects achieved by the utility model are as follows:
[0015] The utility model discloses a low-cost short-focus projection lens, which adopts a full-plastic aspheric lens method for the optical system, reduces the focal length through reasonable collocation and optimization of materials, and achieves a projection ratio of 0.9:1. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 The utility model discloses an embodiment provides a structure schematic diagram.
[0017] In the drawings, the component list represented by each sign is as follows:
[0018] 1, first lens;2, second lens;3, Fresnel mirror;4, LCD display screen. DETAILED DESCRIPTION
[0019] In order to make the purpose and the advantage of the utility model more clear and obvious, the following will be specifically described with the embodiment of the utility model. It should be understood that the following text is only used to describe one or several specific implementation modes of the utility model, and does not strictly limit the protection scope of the utility model.
[0020] As Figure 1 Indicated, a low-cost short-focus projection lens, including first lens 1, second lens 2, Fresnel mirror 3 and LCD display screen 4 in order along the optical axis from object side to image, first lens 1 is the aspheric lens of convex-concave positive focal power, and second lens 2 is the aspheric lens of convex-convex positive focal power.
[0021] Referring to the attached Figure 1 , the material of first lens 1 and second lens 2 is plastic, and the focal length of first lens 1 and second lens 2 is positive.
[0022] According to the above structure, the image side surface of the first lens 1 and the second lens 2 can be convex, concave or flat, the optical power of the first lens 1 is positive, the optical power of the second lens 2 is positive, the optical power is equal to the difference between the image beam convergence degree and the object beam convergence degree, which represents the ability of the optical system to deflect light, the greater the absolute value of the optical power, the stronger the bending ability of the light, the smaller the absolute value of the optical power, the weaker the bending ability of the light, when the optical power is positive, the refraction of the light is convergent, when the optical power is negative, the refraction of the light is divergent, the optical power can be used to represent a certain refractive surface of a lens, also used to represent a certain lens, and also used to represent a system formed by multiple lenses, by fixing each lens in a lens barrel, by reasonably distributing the optical power of the lens, the imaging effect of the low-cost short-focus projection lens is better.
[0023] Referring to the drawings Figure 1 The first lens 1 and the low-cost short-focus projection lens satisfy the following relationship: 1.3<|f1 / f|<2.0, where f1 is the focal length of the first lens 1, f is the optical system focal length of the low-cost short-focus projection lens, the second lens 2 and the low-cost short-focus projection lens satisfy the following relationship: 1.5<|f2 / f|<2.2, where f2 is the focal length of the second lens 2, f is the optical system focal length of the low-cost short-focus lens, the Abbe number of the first lens 1 is less than 35, the Abbe number of the second lens 2 is greater than 50, and a diaphragm is further provided between the image side surface of the first lens 1 and the object side surface of the second lens 2.
[0024] According to the above structure, the first lens 1 is used to collect light and is suitable for lenses with a large field of view, and since the shape of the lens has an important influence on distortion and imaging effect, in order to make the imaging effect better, the design value of the first lens 1 needs to satisfy 1<|CT1 / ET1|<3, where CT1 is the central thickness of the first lens 1, ET1 is the edge thickness of the first lens 1 along the axial direction, where f2 is the focal length of the second lens 2, f is the optical system focal length of the low-cost short-focus lens, the residual aberration is corrected by the second lens 2, the chromatic aberration is reduced and the imaging quality is improved by selecting a lens with a corresponding Abbe number, and the light beam size is controlled, the image brightness is adjusted, the non-imaging light is blocked, and the image quality is improved by the setting of the diaphragm.
[0025] The working principle of the utility model is: the image side surface of first lens 1 and second lens 2 can be convex, concave or flat, the power of first lens 1 is positive, the power of second lens 2 is positive, the power is equal to the difference between the converging degree of the image side and the converging degree of the object side, which represents the ability of optical system to deflect light, the greater the absolute value of power, the stronger the bending ability of light, the smaller the absolute value of power, the weaker the bending ability of light, when the power is positive, the refraction of light is convergent, when the power is negative, the refraction of light is divergent, the power can be used to represent a certain refractive surface of a lens, also can be used to represent a certain lens, also can be used to represent a system formed by multiple lenses, by fixing each lens in a lens barrel, by reasonably distributing the power of the lens, the imaging effect of low-cost short-focus projection lens is better, first lens 1 is used to collect light, and is suitable for a lens with a large field of view, at the same time, since the shape of the lens has an important influence on distortion and imaging effect, therefore, in order to make the imaging effect better, the design value of first lens 1 needs to satisfy 1<|CT1 / ET1|<3, wherein CT1 is the central thickness of first lens 1, ET1 is the edge thickness of first lens 1 along the axial direction, wherein f2 is the focal length of second lens 2, f is the focal length of the optical system of low-cost short-focus lens, by second lens 2 to correct residual aberration, by selecting a lens corresponding to Abbe number, to reduce chromatic aberration and improve imaging quality, by setting the diaphragm, it is convenient to control the size of the light beam, adjust the image brightness, block the non-imaging light, and improve the image quality.
[0026] The above only is the preferred implementation of the utility model, it should be pointed out that, for ordinary technical personnel in the prior art, without departing from the principle of the utility model, still can make a number of improvements and refinements, these improvements and refinements also should be regarded as the protection scope of the utility model. The structure, device and operation method not specifically described and explained in the utility model, such as no special description and limitation, are implemented according to the conventional means in the field.
Claims
1. A low-cost short-focus projection lens, comprising a first lens (1), a second lens (2), a Fresnel mirror (3) and an LCD display screen (4) arranged in order along an optical axis from an object side to an image side, characterized in that: The first lens (1) is a convex-concave positive-power aspherical lens, and the second lens (2) is a convex-convex positive-power aspherical lens.
2. The low-cost short-throw projection lens of claim 1, wherein: The first lens (1) and the second lens (2) are both made of plastic.
3. The low-cost short-throw projection lens of claim 1, wherein: The focal length of the first lens (1) and the second lens (2) is positive.
4. The low-cost short-throw projection lens of claim 1, wherein: The first lens (1) and the low-cost short-focus projection lens satisfy the following relationship: 1.3<|f1 / f|<2.0, wherein f1 is the focal length of the first lens (1), and f is the optical system focal length of the low-cost short-focus projection lens.
5. The low-cost short-throw projection lens of claim 1, wherein: The second lens (2) and the low-cost short-focus projection lens satisfy the following relationship: 1.5<|f2 / f|<2.2, wherein f2 is the focal length of the second lens (2), and f is the optical system focal length of the low-cost short-focus lens.
6. The low-cost short-throw projection lens of claim 1, wherein: The Abbe number of the first lens (1) is less than 35, and the Abbe number of the second lens (2) is greater than 50.
7. The low-cost short-throw projection lens of claim 1, wherein: A diaphragm is further arranged between the image-side surface of the first lens (1) and the object-side surface of the second lens (2).