Design method of energy-adjustable TIR lens
By employing a collimation-then-refraction design that independently handles large and small angles, the problems of light output uniformity and illumination ratio adjustment of TIR lenses are solved, achieving efficient light source energy distribution and uniform illumination effect.
Patent Information
- Application Number
- CN202511755506.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-26
- Publication Date
- 2025-12-26
AI Technical Summary
Existing TIR lenses, while ensuring high light transmission efficiency, struggle to achieve flexible adjustment of light output uniformity and illumination ratio, making it difficult to meet usage requirements.
The design method of independently handling large and small angles is adopted. By collimating and then refractioning the light path, the light source energy is allocated to different angle ranges. The lens model is constructed using freeform surfaces to achieve controllable adjustment of the illumination range and focus.
It improves the light output uniformity and light source utilization of TIR lenses, reduces mutual interference of optical systems, and enhances the flexibility and uniformity of illumination.
Smart Images
Figure CN121209094A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of general lighting, in particular to a TIR lens design method with adjustable energy. BACKGROUND
[0002] As the core secondary optical element of LED light source, the light emission uniformity of TIR lens directly determines the visual effect and application value of scenes such as lighting and display, and is also the core pain point of current technical research and development. The existing TIR lens mostly adopts single parabolic surface or hyperbolic surface structure, although it can achieve high condensing efficiency through total internal reflection, but due to the limitation of light path design, it is easy to appear uniformity problem and cannot change the lighting proportion focus according to the demand, so it is difficult to meet the use demand. The existing improvement scheme in the industry is to grind the exit surface or add diffusion film, the former will cause 5%-15% light flux loss, and the latter will increase the volume and cost of the optical system, so how to improve the light emission uniformity of TIR lens through structure optimization under the premise of ensuring high light transmission efficiency has become the key to break through the current technical bottleneck. SUMMARY
[0003] In view of the above situation, the present application provides a TIR lens design method with adjustable energy, which can modify the lighting range focus according to the use demand, divide the lighting proportion of large and small angles to realize controllable lighting range and controllable lighting focus, and to a certain extent, it can better improve the use flexibility of TIR lens. The specific design scheme is as follows: Determine the light source and receiving surface parameter information, distribute the light source energy and the receiving surface according to the demand. In the present application, take the Lambert point light source as an example, the large and small angle proportion is m-n:n, and the receiving surface is set to a radius of R. According to the light intensity formula of Lambert point light source, the light source energy distribution formula is as follows:
[0004] Where θ max is the maximum divergence angle of the light source, θ c is the large and small angle demarcation angle, n is the proportion of small angle part of light source energy, and m is the total light source proportion.
[0005] After determining the demarcation angle, the light flux of different parts is distributed to determine the incident angle, and the distribution formula is as follows: Small angle range light source distribution:
[0006] The small angle range angle formula is:
[0007] Where N is the number of energy distribution in the small angle range.
[0008] Wide-angle range of light source distribution:
[0009] The formula for obtaining the large angle range is:
[0010] Where N is the number of energy portions distributed over a large angular range.
[0011] After allocating the light source energy, the receiving surface also needs to be allocated, which should be divided into equal-area circular rings. The formula for allocating the receiving surface at small angles is as follows:
[0012] The obtained radius r i It is the horizontal coordinate of the portion of light rays that reach the receiving surface at a small angle.
[0013] The receiving surface at large angles is as follows:
[0014] The obtained radius l i It is the horizontal coordinate of the portion of light rays that reach the receiving surface at a large angle.
[0015] After assigning the light source and receiving surface, independent processing is performed for the large and small angle ranges. For the small angle range, based on the characteristics of the light rays reaching the collimating surface and the refraction surface within the small angle range, two-dimensional coordinate expressions on the two freeform surfaces are derived. According to the vector form of the law of refraction, the iterative relationship of the discrete points of the two freeform surfaces can be obtained. After inputting initial values, the discrete points of the curve are obtained, and then the curve surface shape is obtained. The vector form of the law of refraction is shown below:
[0016] Over a large angle range, since the light rays are refracted once by the cavity sidewalls before reaching the collimating plane, it is necessary to calculate the angle after refraction before calculating the collimating plane. For example... Figure 2 As shown, the tilt angle of the cavity should be set from the processing angle. In this application, it is set to θ degrees. According to the law of refraction, the corresponding angle can be obtained, and then the position of the light incident on the collimating surface of the large angle range can be determined. Similarly, according to the geometric relationship and the vector form of the law of refraction, the discrete point iterative relationship between the collimating surface of the large angle range and the refraction surface of the large angle range can be determined.
[0017] Compared with existing design technologies, the energy-adjustable TIR lens in this application has the advantage of using large and small angle distribution processing. This relatively independent processing method can better complete the energy distribution problem of large and small angles and adjust the illumination range. Moreover, the relative independence can also reduce mutual interference between the two parts, making the processing more convenient.
[0018] The design method of collimating first and then refracting in the large and small angle range can greatly improve the uniformity of the TIR lens, and the utilization rate of the light source is higher. BRIEF DESCRIPTION OF DRAWINGS
[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows: Figure 1 is a schematic diagram of the overall mechanism in the two-dimensional view in the embodiments of the present application.
[0020] Figure 2 is a schematic diagram of the light ray in the embodiments of the present application.
[0021] Figure 3 is a schematic diagram of the overall light ray in the embodiments of the present application.
[0022] Figure 4 is a schematic diagram of the overall structure in the embodiments of the present application.
[0023] Figure 5 is a schematic diagram of the overall structure in the embodiments of the present application.
[0024] Figure 6 is a schematic diagram of the lens manufacturing method flow in the embodiments of the present application.
[0025] Figure 7 is a result diagram when the large and small angle energy distribution is 1:1 in the embodiments of the present application.
[0026] Figure 8 is a result diagram when the large and small angle energy distribution is 3:7 in the embodiments of the present application. DETAILED DESCRIPTION The drawings needed in the embodiments of the present application will be briefly introduced below. Figures 1-6 And specific examples are given to further and clearly describe the schemes of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. The data initial value parameters, the proportion range size, the material and other basic parameters can be appropriately adjusted. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.
[0027] It should be noted that the diagrams provided in the embodiments of the present application only illustrate the basic structure of the present application in a schematic manner. In the diagrams, only the components related to the present application are shown, not the number, shape and size of the components in actual implementation. In actual implementation, the component layout type can be more complex.
[0028] Reference Figures 1-3 The main structure of the lens is a mirror body, which comprises a cavity, a small-angle range lens, and a large-angle range lens. The cavity is a circular truncated cone hole with a free curved upper surface and a flat lower surface. The small-angle range lens comprises a small-angle range collimating surface and a small-angle range refracting surface and is composed of two free curved surfaces. The large-angle range lens mainly comprises a large-angle range collimating surface and a large-angle range refracting surface and is composed of two free curved surfaces. A light source is at the origin, and light rays are emitted from the light source. Small-angle scattering angle parts pass through the two free curved surfaces of the small-angle range lens to reach a receiving surface for uniform reception. Large-angle scattering angle parts pass through the large-angle range lens to reach the receiving surface for uniform reception.
[0029] First, the parameters of the light source and the receiving surface are determined, and the light source energy and the receiving surface are distributed according to the requirements. In this application, a Lambert point light source is taken as an example. The maximum divergence angle of the light source refers to the maximum divergence angle of a general LED. In this embodiment, it is set to 75°. The energy proportions of the large and small angles are 1:1 and 3:7. The receiving surface is set to a radius of 180, and the distance is 300. The light source energy is distributed according to the light intensity formula of the Lambert point light source as follows:
[0030] Thus, when the large and small energy proportions are 1:1, the demarcation angle θ c1 is approximately 29°.
[0031]
[0032] When the large and small energy proportions are 3:7, the demarcation angle θ c2 is approximately 16° For the small-angle part: the light rays are emitted from the light source, first pass through the first free curved surface, i.e., the small-angle range collimating surface, and are collimated on the free curved surface, changing from the original divergent emission to parallel emission to the axis. The emitted light rays then pass through the second free curved surface, i.e., the small-angle range refracting surface, and are redistributed to the specified receiving surface position on the free curved surface.
[0033] Thus, after the demarcation angle is determined, the light fluxes of different parts are distributed to determine the incident angle size. For the small-angle divergence angle part, the incident angle size distribution formula when the light is emitted from the light source is as follows: Small-angle range light source distribution:
[0034] The small-angle range angle formula is:
[0035] Where N is the total number of energy distribution in the small angle range, N is 650 in the embodiment of the application.
[0036] After the light source energy is distributed, the distribution receiving surface is distributed as an equal-area annulus, and the small angle part receiving surface distribution formula is as follows:
[0037] Thus, the small angle part receiving surface position is determined. Taking the xy coordinate system as an example, the receiving surface position is (r i ,300).
[0038] Similarly, the large angle range light source distribution is as follows:
[0039] The large angle range angle formula is as follows:
[0040] The large angle range receiving surface is as follows:
[0041] Thus, the large angle range receiving surface position coordinates are (l i ,300).
[0042] After the light source and the receiving surface are distributed, the light rays are classified and processed independently according to the angle range difference. For the small angle range, the two-dimensional coordinate expressions on the collimating surface and the refractive surface are derived and established according to the inherent characteristics of the light rays incident to the range; and the iterative relationship of the discrete points of the two free-form surfaces is respectively constructed by combining the vector form of the refraction law. By inputting the initial parameter values, the discrete point data of the curve can be solved, and the specific surface type of the target free-form surface is obtained by fitting. The vector form of the refraction law is as follows:
[0043] Where In and Out are the vector expressions of the incident light and the outgoing light on a free-form surface, respectively.
[0044] For the small angle range, the vector expressions of the incident light and the outgoing light on the collimating surface are (sinθ i ,cosθ i ), (0,1), respectively, and the vector expressions of the incident light and the outgoing light on the refractive surface are (0,1), (r i ,300), respectively.
[0045] With a large angle, because the light first refracts through the cavity side wall before entering the collimating surface, the angle after refraction needs to be calculated before the collimating surface is calculated. As shown in Figure 2 The inclination angle of the cavity is set, which should be based on the machining angle, and in this application, the angle is set to 4°. According to the refraction law and two-dimensional geometric relationship, the corresponding angle size can be obtained, and then the position of the light incident to the large-angle range collimating surface is determined. Similarly, according to the geometric relationship and the vector form of the refraction law, the discrete point iterative relationship of the large-angle range collimating surface and the large-angle range refracting surface is determined. Then the iterative relationship of the complete free surface is calculated, and the construction of the free surface is completed.
[0046] The principle of this application is to construct a TIR lens model of collimation followed by refraction through the edge ray principle and geometric surface relationship. This model can realize the relative independent solution of large and small angles, largely avoid the mutual influence of the two, and can complete the redistribution of light source energy according to the demand, greatly improve the utilization rate of light source, and at the same time, the design characteristics of collimation followed by refraction utilize multiple free surfaces to largely realize the uniformization of energy on the target plane.
[0047] According to the above summary, referring to Figures 1-6 A range-adjustable TIR lens design method of collimation followed by refraction mainly includes: S1: Determine the illumination target, determine the light source information, and determine the lens size characteristics. According to the demand, the range of light source energy and receiving surface area is divided, the demarcation angle, critical angle, and incident angle distribution are determined, and the receiving surface coordinate distribution is determined.
[0048] S2: According to the demarcation angle and incident angle distribution determined in S1, the two-dimensional coordinate general formula of the small-angle range collimating surface and the small-angle range receiving surface is determined by combining the edge ray principle.
[0049] S3: According to the two-dimensional coordinate general formula determined in S2, and the lens size information determined in S1, and combining the vector form of the refraction law, the iterative general formula of the small-angle range collimating surface and the small-angle range receiving surface is obtained, the initial value of the two free surface discrete points is given, and the discrete points are connected to form a free surface.
[0050] S4: The light in the large-angle range is emitted from the light source and refracts once through the cavity on the cavity round table wall. The demarcation angle and incident angle distribution determined in S1 are used to determine the light coordinate incident to the large-angle range collimating surface according to the angle relationship of refraction.
[0051] S5: According to the principles of S1 and S2, the discrete points of the large-angle range collimating surface and the large-angle range refracting surface are determined, and then the free surface of the large-angle range is determined.
[0052] S6: The obtained free-form surface is closed connected and properly cut to form a closed two-dimensional figure.
[0053] S7: The obtained two-dimensional figure is rotated 360° around the central axis to obtain a lens model.
[0054] It should be noted that the length units involved in the embodiments of the present application are all in millimeters.
Claims
1. A method for designing an energy-adjustable TIR lens, characterized in that... Includes the following steps: S1: Determine the illumination target, the light source and other information, and the lens size characteristics. Divide the range of light source energy and receiving surface area according to the requirements, and determine the boundary angle, critical angle, incident angle allocation and receiving surface coordinate allocation. S2: Based on the boundary angle and incident angle determined by S1, and combined with the principle of edge rays, determine the two-dimensional coordinate formula of the collimating surface (1) and the receiving surface (2) in the small angle range; S3: Based on the two-dimensional coordinate formula determined by S2 and the lens size information determined by S1, and combined with the vector form of the law of refraction, the iterative formulas of the collimating surface (1) and the receiving surface (2) in the small angle range are obtained. After giving the initial values, two freeform surface discrete points can be obtained. Connect the discrete points to form a freeform surface. S4: The light with a large angle range is emitted from the light source (11), passes through the cavity (7), and is refracted once on the truncated wall (3) of the cavity. Based on the dividing angle and incident angle determined by S1, the coordinates of the light rays incident on the collimating plane (4) with the large angle range are determined in combination with the angle relationship of refraction. S5: Based on the principles of S1 and S2, determine the discrete points of the collimation surface (4) and the refraction surface (5) in the large angle range, and then determine the freeform surface in the large angle range. S6: Close and connect the resulting freeform surface and trim it appropriately to form a closed two-dimensional graphic. S7: Rotate the obtained two-dimensional graphic 360° around the central axis to obtain the lens model.
2. The energy-adjustable TIR lens design method described in claim 1, characterized in that, The steps for determining the light source information and lens size are as follows: The position of the light source is determined as point O. Taking the position of the light source (11) as the origin, the vertical coordinate y of the collimation plane (1) in the small angle range is determined according to the required lens size. 11 The inclination angle of the cavity sidewall (3) is determined as θ, and the initial ordinate position of the collimation plane (4) with a large angle range on the cavity sidewall (3) is determined as y. 21 .
3. The energy-adjustable TIR lens design method described in claim 1, characterized in that, The steps described are as follows: Determining the boundary angle, critical angle, incident angle allocation, and receiving surface coordinate allocation. The energy of the light source is redistributed based on the luminous intensity of the light source to determine the size of the dividing angle; the critical angle is determined by the maximum divergence angle of the selected LED light source. The angle distribution of the incident angle is obtained by dividing the energy of the light source at large and small angles into N equal parts using the luminous flux formula, thereby obtaining the incident angle of the light rays within the entire divergence angle range. After determining the range of the target surface, divide the large and small angle portions of the target surface into equal areas, and divide the two parts into equal-area annexes. The radius of the annexes is the horizontal coordinate position of the light reaching the receiving surface.
4. The energy-adjustable TIR lens design method described in claim 1, characterized in that, The steps for determining the two-dimensional coordinate formulas of the collimating surface (1) in the small angle range, the refractive surface (2) in the small angle range, the collimating surface (4) in the large angle range, the receiving surface (5) in the large angle range, and the cavity sidewall (3) are as follows: The light rays originate from the light source (11) and arrive at the collimating surface (1) in the small angle range. The two-dimensional expressions of the incident and outgoing rays can be represented. The iterative expression of the surface is solved by combining the vector expression of the refraction theorem. For the refraction surface (2) in the small angle range, its horizontal coordinate position is consistent with the horizontal coordinate position of the collimating surface in the small angle range. The increment of the vertical coordinate is the thickness of the lens (8) in the small angle range. The cavity sidewall (3) is a linear function with an angle of θ with the positive longitudinal axis. The light rays start from the light source (11) and are refracted on the cavity sidewall (3). The refracted light rays reach the collimating surface (4) of the large angle range. The two-dimensional expressions of the incident and outgoing rays can be expressed. The iterative expression of the surface is solved by combining the vector expression of the refraction theorem. For the large angle range refraction surface (5), its horizontal coordinate position is consistent with the horizontal coordinate position of the collimating surface of the large angle range. The increment of the vertical coordinate is the thickness of the large angle range lens (9).