JP4987866B2 - Dual paraboloidal reflector and dual ellipsoidal reflector system with optimized magnification - Google Patents

Description

  The present invention relates to a system for collecting-condensing electromagnetic radiation, in particular an asymmetric paraboloid for collecting radiation emitted from a radiation source and focusing the collected radiation on a target. The present invention relates to a system incorporating a reflector.

[Related applications]
This application is filed with US provisional application no. No. 60 / 695,934, which is a US provisional patent application no. No. 60 / 192,321 filed on Sep. 27, 2000, claiming priority. 09 / 669,841 (currently US Pat. No. 6,634,759), filed September 12, 2003, application no. No. 10 / 660,492, filed on Nov. 14, 2005. This is a partial continuation of 11 / 274,241. All of these are hereby incorporated by reference.

  The functional purpose of the system that collects, agglomerates and couples electromagnetic radiation towards a waveguide, such as a single fiber or fiber bundle, or outputs it to a projector homogenizer is to maximize the intensity of the electromagnetic radiation at the target (i.e. Maximizing its flux intensity). The prior art includes so-called on-axis reflector systems related to spherical, elliptical, and parabolic reflectors, and spherical, toroidal, and elliptical reflectors. Teaches the use of off-axis reflector systems related to When the target size approximates the size of the arc gap of the electromagnetic radiation source, the off-axis reflector system achieves higher efficiency and higher brightness at the target than the on-axis reflector system, thereby reducing the light Maximize the amount of light that can be collected by the fiber target. For targets that are much larger than the arc gap dimension of the electromagnetic radiation source, both on-axis and off-axis reflector systems collect, aggregate, and combine radiation from the radiation source into the waveguide. It is effective for.

  The light collecting and light aggregating system has various optical members such as a reflector and a lens that receive light energy from a light source such as a light bulb and direct the light energy toward a target. In particular, the optical system collects and aggregates electromagnetic radiation and couples the light energy into a standard waveguide, such as a single fiber or fiber optic bundle, or outputs the light energy to a projector homogenizer. . The functional purpose of the optical system is to maximize the intensity of electromagnetic radiation (ie, bundle intensity) at the target.

  An optical system for collecting and aggregating light from a light source is generally classified into either an on-axis type or an off-axis type. In the on-axis system, the reflector is located on the optical axis between the light source and the target. FIG. 1 illustrates a known on-axis system that uses a parabolic reflector with an imaging lens. This parabolic reflector is characterized in that light energy emitted from the focal point is substantially collimated (parallelized) and travels parallel to the optical axis. The optical system of FIG. 1 takes advantage of the same features of a parabolic reflector by placing the light source at a focal point to collimate the light from the light source. An aggregating lens located in the light stream receives this collimated light energy and directs the light energy toward the target. In this way, light energy is collected and aggregated on the target. Since a parabolic reflector is used, various optical filters can be used to further improve the durability of the optical system. However, the divergence of light varies continuously along the reflector, and especially light rays traveling near the optical axis show the greatest divergence. As a result, the magnification of the system changes depending on the various optical paths followed by the light emitted from the light source, resulting in degradation of system brightness. In addition, the focusing lens produces a distorted image even under perfect conditions, but in actual operation it usually forms an aberrated image, which effectively increases the image size, Reduce the bundle density at the target.

  FIG. 2 illustrates another known optical system. This system uses an ellipsoidal reflector and has the feature that all of the light emanating from one focus is directed to the second focus. The optical system of FIG. 2 uses an ellipsoidal reflector in which the light source is located at the first focus and the target is located at the second focus. Similar to the previous system, in this on-axis elliptical system, the divergence of light continuously changes along the reflector, and in particular, the brightness degradation caused by the light rays traveling near the optical axis exhibit the greatest divergence. There's a problem.

  Overall, on-axis systems generally have the fundamental limitation of loss of brightness in the combination, thereby reducing the overall efficiency of the light illumination and projection system. In particular, the divergence of reflected light in known on-axis systems reluctantly depends on the angle of radiation from the radiation source. Furthermore, the output of the on-axis system is substantially circular and symmetric, and may therefore be unsuitable for non-circular targets such as rectangular homogenizers used for projection.

  In the off-axis type condensing system, the reflector is arranged off the optical axis between the light source and the target. For example, FIG. 3 shows that the light source is located at the focal point of the retro-reflector and the target is located at the focal point of the main reflector, but these reflectors are located off the optical axis between the light source and the focal point. Show. In the optical system shown here, light energy from the light source is reflected from the retro-reflector and travels to the main reflector. The light energy is then reflected from the main reflector and converges to the target.

  In the off-axis system of FIG. 3, the magnification is very close to 1: 1 for all angles of light when the aperture ratio of the system is small. If the system uses a mirror with a higher aperture ratio (eg, trying to collect more light energy from the same light source), the relatively large angle light beam is reflected at a large divergence angle, so the magnification is Deviation from 1: 1. Thus, again, the brightness at the target decreases due to the enlargement, and the performance of the optical system as a whole decreases. The amount of magnification shift varies depending on the size of the mirror, the radius of curvature, the separation distance between the arc lamp and the target, and the like. Thus, the off-axis system of FIG. 3 is more suitable for applications that use a relatively small aperture ratio.

  Another type of off-axis optical system is also known. For example, US Pat. US Pat. No. 4,757,431 (Patent Document 1) discloses agglomeration and collection using an off-axis spherical concave reflector that enhances the maximum bundle density to irradiate a small target and the amount of bundle density that can be collected by the small target. The system is provided. The enhancement to the optical system of Patent Document 1 is disclosed in US Pat. No. 5,144,600 (Patent Document 2), and U.S. Pat. 5,430,634 (Patent Document 3). The toroidal system described in Patent Document 3 corrects astigmatism, and the elliptical system in Patent Document 2 provides more accurate coupling than the spherical reflector in Patent Document 1, but each of these systems is It requires the application of an optical coating to highly curved reflective surfaces, such optical coatings are relatively expensive and difficult to apply with uniform thickness.

  Overall, the known off-axis optical system provides a near-to-one (ie, unenlarged) image of the light source at the target and maintains brightness. However, in these known off-axis optical systems, the magnification shifts from 1: 1 as the amount of light collected increases with increasing reflector collection angle. Thus, the overall performance of the optical system degrades as a greater portion of the light energy from the light source is collected to increase the light intensity.

  In order to address the problems of the known light collection and aggregation system, US Pat. US Pat. No. 6,672,740 is a dual paraboloid on the optical axis that is advantageous in many respects, including achieving near one-to-one magnification in the case of small sized light sources, relative to the known system. Shaped reflectors. As shown in FIG. 4, the light collecting and aggregating system uses two substantially symmetrical parabolic reflectors, and these reflectors correspond to the light reflected from the first reflector by the second reflector. It is arranged to be received by the part to be. Specifically, the light emitted from the light source is collected by the first parabolic reflector and collimated toward the second reflector along the optical axis. The second reflector receives this collimated light beam and focuses this light on a target located at the focal point.

  To facilitate the description of this optical system, FIG. 4 shows the optical paths (a, b and c) of three different rays emitted from the light source. The ray a travels a relatively short distance before intersecting the first parabolic reflector, but the divergence of the ray a at the first parabolic reflector is relatively large. In contrast, ray c travels further between the light source and the first parabolic reflector, but the relative divergence at the first parabolic reflector is much smaller. Ray b located between rays a and c travels an intermediate distance before intersecting the first parabolic reflector and has an intermediate divergence. In this optical system, due to the symmetry of the two paraboloidal reflectors, the rays a, b and c have the same distance between the second paraboloidal reflector and the target, and the second paraboloidal surface. Is reflected at the corresponding position of the second parabolic reflector so that the distance between the reflector and the target is equal to the distance between the light source and the first parabolic reflector. In this way, the second reflector cancels the divergence. As a result, the optical system collects and aggregates the light energy from the light source at a magnification of approximately 1: 1, and maintains the luminance of the light source.

  The optical system of FIG. 4 further captures radiation emanating from the light source in a direction away from the first parabolic reflector, and the first paraboloid for reflecting the captured radiation back through the light source. A retro reflector can be used in combination with a reflector. Specifically, the retro-reflector is generally spherical and its focal point is located substantially close to the light source toward the first parabolic reflector (ie, the focal point of the first parabolic reflector), thereby The intensity of the reflected collimated light is increased.

  Since the advent of the on-axis dual paraboloidal optical system, the light source is very close to the apex side of the reflector in the above-described on-axis dual paraboloidal optical system. Create a large divergence angle near (ie, along a path similar to ray a). Specifically, light energy traveling along a path similar to ray a with a large divergence angle surrounds a relatively large area on the second paraboloidal reflector, thereby resulting in unintentional aberrations and luminance loss. . However, none of these documents describe a system that handles a large divergence angle and optimizes the magnification between the light source and the focused image in order to obtain maximum bundle strength with minimum distortion at the target. Absent.

U.S. Pat. No. 4,757,431 US Pat. No. 5,144,600 US Pat. No. 5,430,634 US Pat. No. 6,672,740

  Accordingly, there is a need to provide a method for collecting and aggregating electromagnetic radiation that uses an asymmetric parabolic reflector to maximize the bundle intensity of the focused radiation at the target.

  In accordance with one embodiment of the present invention, an improved system for collecting and aggregating electromagnetic radiation uses asymmetric reflectors opposite each other and a magnification between the light source and the focused image at the target. To produce the maximum focus intensity at the target. Specifically, the present invention collects electromagnetic radiation from a source of electromagnetic radiation and focuses the collected radiation onto a target irradiated by at least a portion of the electromagnetic radiation generated by the light source. About. The apparatus has first and second reflectors, each of which is composed of a part of a spheroid or a paraboloid, and has an optical axis A and a focal point on the optical axis A. A light source located in the vicinity of the focal point of the first reflector produces collimated radiation of radiation reflected from the first reflector in a direction parallel to the optical axis A. The second reflector is composed of a part of a spheroid or a paraboloid of revolution, and has an optical axis B and a focal point on the optical axis B. The second reflector is positioned and oriented with respect to the first reflector such that the radiation reflected from the first reflector is reflected by the second reflector and directed toward a target located near the focal point of the second reflector. ing. The first and second reflectors have slightly different shapes and sizes. Alternatively, the position and orientation of the second reflector are set with respect to the first reflector so that the radiation reflected from the first reflector converges at the focal point of the second reflector. The radiation then travels until it is reflected by the second reflector and focused toward a target located near the second focal point of the second reflector. Alternatively, the first and second reflectors can be optically substantially asymmetrically aligned with each other to optimize the magnification.

  Capturing radiation emitted by the light source in a direction away from the first parabolic reflector, and reflecting the captured radiation back through the light source (ie, through the focal point of the first reflector). Thus, a retro-reflector can be used in combination with the first parabolic reflector to increase the intensity of the reflected light beam.

  The first and second reflectors can be arranged in a facing relationship in which the optical axes are located in parallel with each other, or can be arranged so that the optical axes are located at an angle to each other, in which case A redirecting reflector is used to direct the light reflected by the first reflector to the second reflector.

  According to one embodiment of the present invention, the first and second reflectors are composed of a pair of asymmetric elliptical and hyperbolic surfaces, and one of the first and second reflectors has a substantially elliptical shape. The other of the first and second reflectors has a corresponding substantially hyperbolic surface shape, and each of the reflectors of the ellipsoid / hyperbolic surface pair is of radiation reflected by the surface portion of the first reflector. Each light beam is reflected towards the target by a corresponding surface portion of the second reflector, and preferably has a size corresponding to each other so as to optimize the magnification between the light source and the focused image on the target. Optical orientation.

  According to one embodiment of the present invention, an optical device for irradiating a target with electromagnetic radiation includes a first reflector and a second reflector. The first reflector has a first focal length, a first focal point, and a first optical axis, and the electromagnetic radiation is directed substantially near the first focal point of the first reflector. The second reflector has a second focal length, a second focal point, and a second optical axis that does not coincide with the first optical axis. The second reflector receives at least a portion of the radiation reflected from the first reflector to the first reflector and directs the portion of the radiation toward a target located substantially near the second focal point of the second reflector. As such, the position and orientation are set. The second reflector is asymmetric with respect to the first reflector.

  According to one embodiment of the present invention, the focal length of the second reflector is longer than the focal length of the first reflector, thereby reducing the incident angle of the radiation input to the target, thereby reducing the Fresnel reflection loss. Let

  According to one embodiment of the present invention, the asymmetric characteristics of the first and second reflectors are selected to maximize the net output coupling efficiency.

  According to one embodiment of the present invention, the focal length difference between the focal lengths of the two reflectors optimizes the trade-off between Fresnel reflection loss and image aberration, thereby maximizing the net output coupling efficiency. Selected as

  According to one embodiment of the present invention, an optical device for irradiating a target with electromagnetic radiation includes a first reflector and a second reflector. The first reflector has a first focal length, a first focal point, a second focal point, and a first optical axis. The electromagnetic radiation is directed substantially near the first focal point of the first reflector, is reflected from the first reflector, and is substantially converged at the second focal point. The second reflector has a second focal length, a first focal point, and a second optical axis that does not coincide with the second focal point and the first optical axis. The first of the second reflector is such that the target receives at least part of the radiation that passes through the second focal point of the second reflector and is reflected by the second reflector and substantially converges at the first focal point of the second reflector. It is arranged in the vicinity of the focal point. The second reflector is arranged and oriented with respect to the first reflector so that the second focal point of the first reflector and the second focal point of the second reflector are located in the vicinity of each other. The second reflector is asymmetric with respect to the first reflector, which optimizes the net output coupling efficiency.

  According to one embodiment of the invention, a method is provided for collecting electromagnetic radiation and focusing the collected radiation on a target. The method directs electromagnetic radiation to a near vicinity of a first focal point on a first axis of the first reflector, the first reflector receiving at least a portion of the radiation reflected from the first reflector. Positioning and orienting the reflector relative to the reflector, and positioning the target in the vicinity of the focal point of the second reflector so as to receive at least a portion of the radiation reflected from the second reflector, wherein Fresnel reflection In order to effectively reduce losses, the second reflector is asymmetric with respect to the first reflector.

  According to one embodiment of the invention, a method is provided for collecting electromagnetic radiation and focusing the collected radiation on a target. This method approximates electromagnetic radiation to a first focal point on the first optical axis of the first reflector so that the first reflector focuses the radiation reflected from the first reflector to a second focal point on the first optical axis. The second reflector is disposed so that the first focal point on the second optical axis of the second reflector is located substantially in the vicinity of the second focal point of the first reflector, thereby reflecting from the first reflector. The focused radiation passes through the first focal point of the first reflector and is redirected by the second reflector toward the second focal point on the second optical axis, and the target is directed to the second focal point of the second reflector. Wherein the second reflector is asymmetric with respect to the first reflector in order to effectively reduce the Fresnel reflection loss.

  A filter or other optical element can be provided between the collimating reflector and the focusing reflector.

  The shape of the first and second reflectors may deviate from an ellipsoid or a paraboloid depending on system requirements. Similarly, the first and second reflectors may have a toroidal shape close to an ellipse or a spherical shape close to an ellipse.

  Embodiments of the present invention will be described with reference to the accompanying drawings, in which like elements or features are indicated by like reference numerals in the different figures.

  Embodiments of the present invention will be described with reference to the drawings. These examples are illustrative of the principles of the present invention and should not be construed as limiting the scope of the invention.

  Referring to FIGS. 5-6 and 8-10 illustrating exemplary embodiments of the present invention, the present invention includes the following four major components: electromagnetic light source 10, first reflector 20, and second reflector. 30 and a target or tapered light pipe (TLP) 50 are associated.

  The electromagnetic light source 10 is preferably a light source having an envelope 12. Most preferably, the electromagnetic light source 10 is an arc lamp such as a xenon lamp, a metal halide lamp, an HID lamp, or a mercury lamp. For some applications, as detailed below, filament lamps such as halogen lamps can be used if the system is modified to fit the lamp's non-opaque filaments. However, any electromagnetic radiation light source (eg, fiber, filament lamp, gas discharge lamp, laser, LED, semiconductor, etc.) can be used if the size of the light source approximates or is small.

  Here, the size of the electromagnetic light source is better defined by the 1 / e-fold intensity of the intensity contour map characterizing the brightness (bundle density over the angular range) of this light source. Luminance is related to the size of the arc gap and determines the theoretical limit of coupling efficiency. In the arc lamp example, the contour line approximates the symmetry in the axial direction, and is a composite function of electrical rating, electrode design, composition, gas pressure, arc gap size, and gas composition. In an arc lamp embodiment having an aspheric envelope, the effective relative position and intensity distribution of the electromagnetic light source imaged by the reflector is subject to aberrations. This is caused by the shape of the envelope acting essentially as a lens, requiring an optical element to cancel. Optical cancellation can be achieved by altering the reflector design to cancel the astigmatism caused by the envelope, or by inserting corrective optics between the electromagnetic light source and the target. In addition, an optical coating can be applied to the envelope to minimize Fresnel reflections, thereby maximizing the radiation that can be collected at the target or controlling and / or filtering the radiant flux. .

The first reflector 20 is composed of a part of a spheroid having an optical axis 22 and focal points 24 and 26. The first reflector 20 preferably has a reflective coating 28 (eg, aluminum or silver) whose surface is well polished. Depending on the application, the first reflector 20 can be formed from glass coated with a wavelength selective multilayer dielectric coating. For example, the reflective coating 28 can be a cold coating that exhibits high reflectivity only in the visible wavelength range for application to visible light. When the light source 10 is disposed at the first focal point 24 of the first reflector 20, the electromagnetic radiation that strikes the first reflector 20 is reflected as an energy beam that converges on the second focal point 26 of the first reflector 20. When the light source 20 is an arc lamp, the arc gap is preferably smaller than the focal length of the first reflector 20.

The second reflector 30 is constituted by a part of a spheroid having an optical axis 32 and focal points 34 and 36. As described above, the second reflector 30 can also include a coating 38 that selectively reflects light energy. The second reflector 30 may be different in shape or size from the first reflector 20. In this case, the first and second reflectors are asymmetric with each other.

  The position and orientation of the second reflector 30 are set so that the electromagnetic radiation reflected by the first elliptical reflector 20 converges on the second focal point 36 of the second reflector 30. The radiation travels until it hits the surface of the second reflector 30, and then is focused toward the first focal point 34 of the second reflector 30. In order to optimize the magnification between the first reflector 20 and the second reflector 30 (i.e., an image of substantially the same size as the light source is focused) To achieve focusing at one focal point 34, each line of electromagnetic radiation reflected and focused by the surface portion of the first reflector 20 is reflected by the substantially corresponding surface portion of the second reflector 30. It is important to be scorched. In order to achieve focusing at the first focal point 34 having the maximum brightness possible, the magnification between the first reflector 20 and the second reflector 30 is optimized (ie substantially the same as the light source). Each line of electromagnetic radiation reflected and focused by the surface portion of the first reflector 20 is reflected by the substantially corresponding surface portion of the second reflector 30. It is important to be scorched. In the context of this disclosure, the position and orientation of the first reflector 20 and the second reflector 30 are such that each line of electromagnetic radiation collimated by the surface portion of the first reflector 20 is substantially equal to the second ellipsoidal reflector 30. It is set to be focused by the surface portion corresponding to.

  The target 50 is a small object that requires the highest possible intensity of illumination. In one embodiment of the present invention, the target 50 is a light pipe, a tapered light pipe, a single core optical fiber, a fused bundle of multiple optical fibers, a fiber bundle, etc., as shown in FIG. This is a waveguide. The input end of the target (eg, the proximal end of the optical fiber) is positioned at the first focal point 34 of the second reflector 30 to receive the focused radiation of the electromagnetic radiation reflected by the second reflector 30. Yes.

  When the light collection and aggregation system of the present invention is suitable for illumination or image projection applications, it is necessary to homogenize the output intensity profile at the target so that the output is more uniform. For example, in illumination during medical procedures such as endoscopy, it is desirable to obtain uniform illumination so that the doctor can observe the central area and the peripheral area of the illumination with equal clarity. In the case of illumination using an optical fiber, if a uniform intensity is obtained, it is possible to couple a higher output to a specific optical fiber structure without damage from hot spots. In the case of projection, a uniform intensity may be required to create a uniform intensity profile on the screen. In particular, for visual aesthetics, it is desirable that the center and the periphery of the display image have the same level of illumination.

  Therefore, as shown in FIG. 5, the target may be a homogenizer that adjusts the output luminance profile. The waveguide may have a polygonal cross section (square, rectangular, triangular, etc.) as shown in FIGS. 7a-7f, or a rounded cross section (circular, oval, etc.) as shown in FIGS. 7g-7h. Can be.

  Depending on the output requirements regarding the aperture ratio and size, the homogenizer may be tapered from small to large, or vice versa. In this case, the target 50 can be a tapered waveguide that gradually increases as shown in FIG. 7i or a tapered waveguide that gradually decreases as shown in FIG. 7j. In this way, the homogenizer can change the output shape of the illumination. For example, in a projection display that produces a projected image 70 by placing a light source 60 in the output stream of the target 50 via a condenser lens 80 and a projection lens 90, the ideal output of the homogenizer is in the form of the display. Depending on the ratio, the width to height ratio would be 4 to 3 or 16 to 9 or some other rectangular shape. However, the illumination radiation angles in both directions should be approximate, and therefore the optical projection system 90 should be able to be used efficiently in this optical system.

  Although the target and light source are closely related to the collection and aggregation system of the present invention, the system according to one embodiment of the present invention shares a single focal point (ie, the second focal point 26 and the second focal point 26 of the first reflector 20). Two reflectors are used that are slightly different in size and / or shape so that the second focal point 36 of the two reflectors 30 is located at substantially the same position.

  Continuing the description of the collecting and aggregating system, in the configuration shown in FIGS. 5 and 6, the first reflector 20 and the second reflector 30 are arranged in a face-to-face relationship facing each other so as to be concave. 5 and 6, the first reflector 20 and the second reflector 30 are configured such that the optical axes 22 and 32 are on the same straight line, and the reflecting surface of the first reflector 30 is optimized to optimize the magnification. Optical symmetry is achieved by disposing the second reflector 30 so as to be in an opposing-facing relationship with respect to a substantially corresponding reflecting surface.

  In FIGS. 5-6, three rays a, b and c are shown to illustrate the action of both reflectors in terms of the various possible paths of electromagnetic radiation produced by the light source 10. In FIGS. 5-6, the rays a, b, and c are in substantially the same positions as in FIG. 4 to show the effectiveness of the optical system of the present invention to reduce aberrations. Each light ray a, b, and c emitted from the light source 10 collides with a different point on the first reflector 20, and each point is at a different distance from the light source 10. However, each ray a, b and c is also focused on the target 50 from the corresponding position of the second reflector 30, so that for these three rays the magnification is substantially 1: 1 or a slight increase. Is producing.

  As before, ray a produces the greater divergence compared to rays b and c because the distance from light source 10 and first reflector 20 is the shortest. In the optical system of the present invention, the radiation from the light source is focused from the first focal point 24 of the first reflector 20 to the second focal point 26. As a result, the travel distance of the radiation from the light source 10 is larger than the corresponding distance in the system of FIG. 4 using a parabolic reflector, even if it is emitted at a large angle, such as ray a. Since the distances of rays a, b and c are now relatively uniform, this large distance reduces the amount of aberration.

  To further reduce aberrations, FIG. 6 shows that the first reflector 20 ′ and the second reflector 30 ′ have greater eccentricity (ie, the first and second reflectors 20 ′ and 30 ′ are more circular). (Near) illustrates an embodiment of the present invention. In this embodiment, the radius of curvature of the first and second reflectors 20 'and 30' is large, resulting in a distance between the first focal point 24 'of the first reflector 20' and the first focal point 34 'of the second reflector 30'. Is decreasing. At the same time, the increase in the radius of curvature of these reflectors 20 'and 30' increases the distance along the ray a between the first reflector 20 'and its first focal point 24'. Similarly, the distance along the ray a between the second reflector 30 'and its first focal point 34' increases. As a result, the moving distance between the radiation source 10 'and the first reflector 20' for the rays a, b and c in FIG. 6 is more uniform than in the embodiment of FIG. This feature allows the system to reduce aberrations between the light source and the target, even in the case of electromagnetic energy moving in the vicinity of the optical axis 22 ', such as an energy path similar to the ray a.

  By comparing the same ray c path in FIGS. 5 and 6, the reflectors 20 ′ and 30 ′ used in the embodiment of FIG. 6 to collect the same angle of output radiation from the light source 10. You can see that it covers the larger part of the ellipse. However, it can be seen that the reflectors 20 ', 30' of FIG. 6 have substantially the same diameter as the reflectors 20 'and 30' of FIG.

  As shown in FIGS. 5 and 6, the collection-aggregation system of the present invention is amenable to the use of a retro-reflector 40, which is shown in the example as a spherical retro-reflector. The retro-reflector 40 is arranged so as to capture electromagnetic radiation emitted by the light source 10 that does not collide with the first ellipsoidal reflector 20 if the retro-reflector 40 is not present. Specifically, the spherical retro-reflector 40 returns so that the radiation emitted from the light source 10 in the direction away from the first reflector 20 is reflected by the retro-reflector 40 and passes through the first focal point of the first reflector 20. Then, it is constructed and arranged so as to face the first reflector 20. The radiation that is additionally reflected by the first reflector 20 is added to the radiation that impinges directly on the first reflector 20 from the light source 20, thereby increasing the intensity of the radiation reflected towards the second reflector 30. Let As a result, the intensity of radiation at the first focal point 34 of the second reflector 30 also increases.

  If a filament lamp is used as the light source 10, the retroreflected radiation is blocked by the opaque filament located at the first focus 24, so that the retroreflector and the radiation pass the first focus 24 of the first reflector 20. It cannot be oriented to return to focus through. In this case, the position of the retroreflector 40 should be adjusted so that the retroreflected radiation does not strictly pass through the first focal point 24 but passes through its vicinity.

  Several types of retro-reflectors 40 are known and any can be used in the present invention. For example, instead of the spherical retro-reflector 40, a retro-reflecting function can be performed by a two-dimensional corner cube array (not shown) having unit elements having the same or smaller size as the arc size of the light source 10. It is. The use of a two-dimensional corner cube array eliminates the need for precise placement of retro-reflectors and creates a tighter focus in the light source 10 arc.

  Furthermore, in the above embodiment, the first and second reflectors have been described as having an elliptical surface or a parabolic shape. However, in the present invention, these first and second reflectors 20 and 30 are ideal elliptical surfaces or parabolic surfaces. It has been found and expected to use a slightly different shape from the object geometry. For example, the first and second reflectors 20 and 30 may have an elliptical or parabolic shape modified to compensate for various parameters such as bulb envelopes and filters. In this case, the deviation in the shape of the substantially elliptical or parabolic reflectors 20 and 30 may be small and the final output may be slightly different from the optimum value. In order to reduce the cost of the reflectors 20 and 30 or to improve performance in special lamp types and arc shapes, reflector shape modifications can be introduced. For example, in the present invention, reflectors 20 and 30 have been found to be similar as toroidal reflectors (with two vertical and different radii of curvature) or spherical reflectors that can be manufactured at a lower cost, and , That is expected. If non-elliptical reflectors are used, the output coupling may not be optimal, but the cost savings due to the first and second reflectors 20 and 30 are sufficient justification for losses due to inefficient coupling. To do.

  In a standard DPR system, the two reflectors are symmetric with respect to each other. The arc image is generally not distorted or blurred, as is the case with elliptical or parabolic reflector systems. The coupling efficiency is higher, especially for applications with a small emission area. A feature of a standard DPR system is that light incident on a tapered light pipe or target 50 can reach ± 90 °, which is a glazing angle with high Fresnel reflection loss, as shown in FIG. 8b. Referring now to FIG. 8a, according to one embodiment of the present invention, a dual parabolic reflector (DPR) system 100 includes a first reflector 20 and a second reflector 30 that are asymmetric with respect to each other. Alternatively, the first and second reflectors 20, 30 can be replaced by a single reflector comprising two parts of different shape and / or size. A slight magnification occurs due to the asymmetric relationship between the two reflectors 20 and 30, which causes distortion of the image. However, the light or radiation input to the TPL 50 has a smaller angle of incidence than the standard SDR system, thereby maximizing the net output coupling efficiency.

  According to one embodiment of the present invention, the DPR system 200 of FIG. 9a includes an electromagnetic light source 10, a first reflector 20, a second reflector 30, and a TLP 50, where the two reflectors 20, 30 are a few. Is asymmetrical so that it is magnified. Alternatively, the first and second reflectors 20, 30 can be replaced by a single reflector comprising two parts of different shape and / or size. According to one aspect of the present invention, the second reflector 30 is larger than the first reflector 20 and has a longer focal length than the second reflector 30. Although slight magnification causes a small amount of image distortion, Fresnel loss is reduced because the light or radiation input to the TPL 50 has a smaller angle of incidence than the standard SDR system.

  The first reflector 20 is preferably a parabolic reflector having an optical axis 22 (or focal axis 22), and the second reflector 30 is a parabolic reflector having an optical axis 32 (or focal axis 32). A surface reflector is preferred. The two optical axes 22 and 32 do not coincide. As a result, the light incident on the TLP 50 from the second reflector 30 is shown in FIG. 9b. When the output or second reflector 30 is adjusted to the same focal plane 22 as the input or first reflector 20, the focal axis 32 of the output or second reflector 30 is the DPR system 200, as shown in FIG. Located outside. This reduces the effect of Fresnel reflection because the incident angle is less than ± 90 °.

  The DPR 200 or dual ellipsoidal reflector (DER) system 300 can be designed using ray tracing. The benefits gained by the reduced Fresnel reflection in the present invention are partially lost by slight distortion of the image due to the asymmetry of the DPR or DER system 200. As a result, the system optimizes the tradeoff between Fresnel reflection loss and image aberration or distortion that maximizes net output coupling efficiency.

  In accordance with one embodiment of the present invention, the DER system 200 of FIG. 10 includes an electromagnetic light source 10, a first reflector 20, a second reflector 30, and a TLP 50, where the two reflectors 20, 30 are a few. Is asymmetrical so that it is magnified. According to one aspect of the present invention, the second reflector 30 is larger than the first reflector 20 and has a longer focal length than the second reflector 30. Although a small amount of image distortion is caused by a slight enlargement, the incident angle of the input light to the TPL 50 is small, thereby reducing the Fresnel loss.

The first reflector 20 is preferably an ellipsoidal reflector having an optical axis 22 (or focal axis 22), and the second reflector 30 preferably has an optical axis 32 (or focal axis 32). An ellipsoidal reflector. As shown in FIG. 10, the two optical axes 22 and 32 do not coincide . By this, the incident angle is smaller than ± 90 °, whereby the effect of Fresnel reflection is reduced.

Several specific examples of the present invention are provided below. These examples are intended to illustrate some possible implementations of the invention and are not intended to limit the scope of the invention.
Example

  The first pair of example optical systems according to the present invention uses a low wattage lamp of about 100 watts as its light source. In the reflective system according to the embodiment of FIG. 5, each of the first and second reflectors has a diameter of 2.5 inches, and the separation between the light source and the target (ie, the distance between the focal points) is about 5 inches. It is. In contrast, the highly eccentric low watt reflection system according to the embodiment shown in FIG. 6 uses similarly sized first and second reflectors each having a diameter of about 2.5 inches. The distance between the light source and the target is about 2 inches.

  In high wattage applications, the optical system is made relatively large to accommodate the desired collection of higher electromagnetic energy levels and potentially larger lamps. For example, if a high wattage lamp of about 5,000 watts is used in the configuration of FIG. 5, each of the main reflectors has a diameter of 20 inches and the spacing between the light source and the target is about 40 inches. As before, the embodiment of FIG. 6 uses a similarly sized main reflector, but the distance between the light source and the target is reduced. For example, the embodiment of the high watt optical system according to the embodiment of FIG. 6 also has first and second reflectors with a diameter of about 20 inches, but the distance between the light source and the target is 16 inches.

  While the invention has been described above, various modifications will be apparent to those skilled in the art without departing from the spirit and scope of the invention. All these modifications are understood to fall within the scope of the claims.

Schematic diagram illustrating in cross section a known on-axis agglomeration-collection optical system using a parabolic reflector and a focusing lens. Schematic diagram showing in cross section a known on-axis agglomeration-collection optical system using an ellipsoidal reflector. Schematic diagram showing a known off-axis agglomeration-collection optical system in cross-section. Schematic diagram showing in cross-section a known on-axis agglomeration-collection optical system using two parabolic reflectors. FIG. 2 is a schematic diagram illustrating, in cross-section, a known off-axis agglomeration-collection optical system using two larger parabolic reflectors, according to an embodiment of the present invention. Sectional view of an aggregation-collection optical system using two reflectors with greater eccentricity according to embodiments of the present invention Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic cross-section of multiple waveguide targets that can be used in embodiments of the present invention. Schematic of a dual parabolic reflector system according to an embodiment of the present invention. Schematic of the angle of incidence for a standard parabolic reflector system. Schematic of a dual parabolic or ellipsoidal reflector system according to an embodiment of the present invention. Schematic of a dual parabolic or ellipsoidal reflector system according to an embodiment of the present invention. Schematic of a dual parabolic or ellipsoidal reflector system according to an embodiment of the present invention.

Claims (29)

An optical device for illuminating a target with electromagnetic radiation, comprising:
A first reflector having a first focus and a first optical axis, the electromagnetic radiation is directed in the vicinity of the first focus of the first reflector;
A second reflector having a second focal point and a second optical axis, the second reflector receives at least a portion of the radiation reflected from the first reflector to the first reflector, and the one of the radiations. parts so as to reflect the target located in the vicinity of the second focal point of the second reflector and arrangement, are oriented, the second reflector Ri asymmetric der to said first reflector,
The first reflector has a first focal length, the second reflector has a second focal length different from the first focal length;
Wherein the second focal length of the second reflector is longer than the first focal length of the first reflector, the optical device thereby characterized Rukoto reduce the angle of incidence of the radiation to be input to the target .   The optical apparatus of claim 1, wherein the asymmetry of the first and second reflectors is selected to maximize output coupling efficiency. The focal length difference between the second focal length and said first focal length, according to claim 1, characterized in that it is selected to optimize the tradeoff between Fresnel reflection loss and image aberration Optical device.   2. The optical device according to claim 1, wherein each of the first and second reflectors includes at least a part of a spheroid or a paraboloid of revolution.   2. The optical device according to claim 1, wherein each of the first and second reflectors includes at least a part of a spheroidal surface or a rotating toroid surface.   The optical apparatus according to claim 1, wherein the second optical axis does not coincide with the first optical axis. The per part of the electromagnetic radiation directly to said first reflector, said portion of electromagnetic radiation which does not hit directly the first reflector, and said apparatus further, to increase the flux intensity of the convergence line An additional reflector configured and arranged to reflect at least a portion of the portion of the electromagnetic radiation that does not directly impinge on the first reflector toward the first reflector through the first focal point of the first reflector; The optical apparatus according to claim 1, further comprising: The additional reflector reflects the electromagnetic radiation emitted away from the first reflector to the first reflector via the first focal point of the first reflector and to the first reflector of the first reflector. The optical apparatus according to claim 7 , further comprising a spherical retro-reflector disposed on the opposite side of the first reflector. Said first optical axis and the second optical axis are parallel to each other, and said first and second reflectors, opposite - optical device according to claim 1, characterized in that it is arranged in facing relationship .   An image light source illuminated by the radiation collected and aggregated at the target, the image light source including a stored image, and the stored image is projected by the radiation. 1. Optical device.   2. The optical device according to claim 1, wherein each of the first and second reflectors has a diameter larger than a distance between the first focal point of the first reflector and the target.   The optical device according to claim 1, wherein the target is a tapered light guide. An optical device for illuminating a target with electromagnetic radiation, comprising:
A first reflector having a first focal point, a second focal point, and a first optical axis; the electromagnetic radiation is directed to the vicinity of the first focal point of the first reflector and reflected from the first reflector; A second reflector that converges to two focal points, and has a first focal point, a second focal point, and a second optical axis, reflected by the second reflector through the second focal point of the second reflector, and the second reflector A target that receives at least a portion of the radiation that converges to the first focal point of the second reflector is located in the vicinity of the first focal point of the second reflector, the second reflector with respect to the first reflector, The second reflector of the first reflector and the second reflector of the second reflector are arranged and oriented so that they are located in the vicinity, and the second reflector is asymmetric with respect to the first reflector Der is,
The first reflector has a first focal length, the second reflector has a second focal length different from the first focal length;
The optical apparatus according to claim 1, wherein the second focal length of the second reflector is longer than the first focal length of the first reflector, thereby reducing an incident angle of radiation input to the target . 14. The optical device of claim 13 , wherein the asymmetry of the first and second reflectors is selected to maximize output coupling efficiency. The focal length difference between the second focal length and said first focal length, according to claim 13, characterized in that it is selected to optimize the tradeoff between Fresnel reflection loss and image aberration Optical device. 14. The optical apparatus according to claim 13 , wherein each of the first and second reflectors includes at least a part of a spheroid. 14. The optical apparatus according to claim 13 , wherein each of the first and second reflectors includes at least a part of a spheroid or a toroidal surface. 14. The optical apparatus according to claim 13 , wherein the second optical axis does not coincide with the first optical axis. The per part of the electromagnetic radiation directly to said first reflector, said portion of electromagnetic radiation which does not hit directly the first reflector, and said apparatus further, to increase the flux intensity of the convergence line And having an additional reflector constructed and arranged to direct at least a portion of the portion of the electromagnetic radiation that does not directly strike the first reflector through the first focal point of the first reflector to the first reflector. 14. An optical device according to claim 13 , characterized in that The additional reflector is related to the first focus of the first reflector to reflect electromagnetic radiation emitted away from the first reflector through the first focus of the first reflector toward the first reflector. The optical apparatus according to claim 19 , further comprising a spherical retro-reflector disposed on the opposite side of the first reflector. Further, the image light source illuminated by the radiation collected and aggregated at the target, the image light source includes a stored image, and the stored image is projected by the radiation. The optical device according to claim 13 . 14. The optical device of claim 13 , wherein each of the first and second reflectors has a diameter that is greater than a distance between the first focal point of the first reflector and the target. The optical device according to claim 13 , wherein the target is a tapered light guide. A method of collecting electromagnetic radiation and focusing the collected radiation on a target, the method comprising the following steps:
Directing the electromagnetic radiation to a vicinity of a first focal point on a first optical axis of the first reflector;
Positioning and orienting a second reflector relative to the first reflector to receive at least a portion of the radiation reflected from the first reflector; and at least a portion of the radiation reflected from the second reflector. placing the target in the vicinity of the focal point of the second reflector to receive, wherein said second reflector in order to optimize the output coupling efficiency Ri asymmetric der to said first reflector,
The first reflector has a first focal length, the second reflector has a second focal length different from the first focal length;
Reducing the incident angle of the radiation input to the target by making the second focal length of the second reflector longer than the first focal length of the first reflector . The method of claim 24 , further comprising selecting asymmetric characteristics of the first and second reflectors to maximize output coupling efficiency. 25. The method of claim 24 , further comprising optimizing a trade-off between Fresnel reflection loss and image aberration so that output coupling efficiency is maximized. A method of collecting electromagnetic radiation and focusing the collected radiation on a target, the method comprising the following steps:
Directing the electromagnetic radiation to the vicinity of the first focal point on the first optical axis of the first reflector so that the first reflector focuses the radiation reflected from the first reflector to the second focal point on the first optical axis. The process of
Arranging the second reflector so that the first focal point on the second optical axis of the second reflector is located in the vicinity of the second focal point of the first reflector, thereby converging the reflected light from the first reflector; Radiation passes through the first focal point of the first reflector and is redirected by the second reflector toward a second focal point on the second optical axis; and the target is moved to the second reflector of the second reflector. placing in the vicinity of the focal point, where, in order to reduce Fresnel reflection losses effectively, the second reflector Ri asymmetric der to said first reflector,
The first reflector has a first focal length, the second reflector has a second focal length different from the first focal length;
Reducing the incident angle of the radiation input to the target by making the second focal length of the second reflector longer than the first focal length of the first reflector . 28. The method of claim 27 , further comprising selecting asymmetric characteristics of the first and second reflectors to maximize output coupling efficiency. 28. The method of claim 27 , further comprising optimizing a trade-off between Fresnel reflection loss and image aberration so that output coupling efficiency is maximized.

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