CZ307029B6 - A light-conducting collector and a colour light mixer with convergent optics - Google Patents

Abstract

Light spot optics of variable traffic signs consisting of a light source (1) in which there is light permeable material is encapsulated by a group miniature LED crystals (2), single arm or multi-armed light guide rods (10; 100), at least one smooth opalescent cavities (115) and dioptre output lenses (40; 120). Single Output Area (38, 39; 108) The light-guide rods (10; 100) are located around the focus the individual exit surfaces (46, 47; 86) of the connecting lens (40; 120). Between at least one exit surface (38, 39; 108) light guide rods (10; 100) and exit face (46; 47; 86) of the continuous lens (40; 120) is smooth an opalescent cavity (115) that is deflected from the plane perpendicular to the optical axis (200) of the exit surface (46, 47; 86) connecting lenses (40; 120) at such an angle that they deflect the refraction or total reflection daylight over the horizon outside the light guide rod exit surface (38, 39; 108) (10; 100). Smaller amounts of daylight that follow passing through the light guide rod (10; 100) to the light source (1), results in greater contrast between dark and light points on a traffic variable markings, making information and symbols light points visible in the day.

Description

Technical field

FIELD OF THE INVENTION The present invention relates generally to an optical system for connecting, blending and transmitting light through a light guide, and more particularly to a convergent optical system for a light spot on a variable traffic sign or traffic information device consisting of LED colored light emitting crystals, shaped light guide bars, opalescent cavities and lighting dioptric lenses.

BACKGROUND OF THE INVENTION

When miniature LED light crystals entered the market, they were commonly used along with shaped plastic light guide bars to illuminate symbols, indicators or buttons on electronic boards. These shaped light guide rods made production cheaper because light was distributed from one light source to multiple locations or to a larger area.

When their luminous efficiency increased during the development of LED light crystals, they were used with light-guide rods as well as in outdoor lighting technology. An example of such use is in the solution of the light point (pixels) of the display panel in US 2013/0 258 700 A1, where, in addition, by grouping several LED crystals in one light point and electronically controlling the power of these LED crystals Especially in the display of texts and symbols in traffic, a narrow beam of light is required for only a few degrees at each individual light point, since the symbols are read from a long distance and in the direction of the lanes. Therefore, in those applications where a narrow beam of light is needed, converging optics with a light output directionality of only a few degrees is necessary in the semi-space of light emitting LED crystals. According to the patent, by combining the LED crystals of the primary colors (red, green and blue), one light guide rod not only mixes these colors, but also reduces the output surface of the convergent lens relative to the output surface of the optical system with one output convergent lens for each LED crystal separately. . The size of the output surface of the convergent lens and its curvature has a significant effect on disturbing reflections from external illumination (parasitic light at the light point).

From the perspective of the recipient of the message from the outdoor display panel, two parameters in its optical-mechanical design are important for readability and safety in traffic - the light output of a single point and the relative ratio (contrast) of luminance (on) these are reflections from the sun and scattered daylight). These parameters are precisely quantified by an international standard for road safety reasons.

An example of an interesting solution to the concentration of light output from LED crystals to light guides is represented by US Patent No. 8,534,890 B2 and one of the preferred solutions aimed at reducing glare from the Sun (and scattered solar radiation) in the LED light point design can be found in EP 0 930 600. In general, therefore, in the design of outdoor display panels, it is necessary to look for light point optical systems with sufficient light output (efficiency) and low reflection from natural daylight.

The light output of today's conventional miniature LED crystals of about 0.3x0.3x0.13 mm is already such that, when concentrated by convergent optics into narrower light beams (usually 0.1 to 0.015 steradians), they may impair visual comfort under certain conditions. That is why LED crystals are usually already powered by smaller outputs, which achieve higher energy efficiency and longer life. Improvement of the contrast (readability) can then be taken into account only by the point of view of the light point with lower disturbing reflections from the Sun and the light scattered from it by the sky.

- 1 GB 307029 B6

The disadvantage of the existing solutions is that the improvement of the contrast (readability) can no longer be efficiently achieved simply by increasing the luminous efficiency of the imaging point optics, but mainly by reducing the disturbing reflections from the Sun.

SUMMARY OF THE INVENTION

These disadvantages are eliminated or substantially reduced by the convergent optic light collector and color light mixer of the present invention, characterized in that a smooth opalescent cavity is disposed between at least one exit surface of the light guide rod and the exit surface of the bonding lens which is diverted from a plane perpendicular to the optical axis of the lens at an angle of at least 6 °, having a minimum thickness of more than 0,2 mm in the direction of the optical axis of the lens and having an upper edge situated above the optical axis of the lens.

The main advantage of the present invention is that it reduces the phantom reflections of the light point from the Sun by causing daylight entering the light point structure through the lens to deflect from the exit of the light guide towards the non-glazed / dark parts of the structure. This deflection of daylight entering the light spot through the lens occurs on a smooth opalescent cavity suitably positioned and inclined between the exit of the light guide (which is near the focus of the lens) and the exit surface of the lens. Most of the daylight above the horizon, this cavity is moved or diverted by refraction, or partially by total reflection, outside the light-guide section of the rod, so this disturbing (erratic, phantomic) light cannot return back after reflecting and scattering the bright and bright portions of the LED light source. a light guide rod into the field of view of the observer, which is the original essence of the invention. The smaller amount of daylight that is scattered on the light source results in greater contrast between the dark and light points on the variable traffic signs, making the information and symbols of the light points displayed in the day more readable.

It is advantageous for each connecting lens to have an optical axis vertically displaced to the lower edge of the respective exit surface of the light guide rod. This reduces the amount of light from the LED crystals that shines above the horizon (and does not fall into the viewer's field of vision), reducing the light pollution of the night sky.

It is also preferred that the opalescent cavity is deflected from a plane perpendicular to the optical axis of the lens at an angle of at least 6 ° and has a minimum thickness greater than 0.2 mm in the direction of the optical axis of the lens. Optimizing the deflection of the opalescent cavity from the vertical plane perpendicular to the optical axis of the lens increases its ability to deflect the incident light off the light guide rod and the minimum thickness of the opalescent cavity ensures its function even in an environment saturated with air humidity where moisture could precipitate in the cavity and micro-droplets partially fill it, which would negatively affect its properties and efficiency.

It is also advantageous if the thickness of the opalescent cavity is constant over the entire cross-section of the opalescent cavity, since such a cavity almost does not distort the luminous distribution in the output light beam. In contrast, in an opalescent cavity whose wedge thickness increases or narrows in the + Z direction (away from the Earth's surface to the sky), its volume can advantageously be minimized at its maximum efficiency in deflecting light falling on it outside the light guide rod.

In the simplest embodiment, the light guide rod is designed as a single-arm with one exit surface. Moreover, with a light guide rod branching away from the light source into two or more arms, the absolute amount of unwanted daylight entering the light point structure can advantageously be reduced.

The absolute amount of daylight entering the light point design depends on the size of the front surface of the transparent output lens. This surface can be minimized in the case of an optical structure with a shaped branching light bar, while still increasing its curvature, which results in

To more effectively disperse unwanted primary reflections of external daylight on this lens front face. Both can be achieved by distributing light from the LED crystals to multiple arms of the light guide in accordance with the following two technical ideas.

The first idea takes into account that instead of using one image in the focal plane of a single lens, we use two reduced images with two lenses with a shorter focus (this shorter focus is no longer than 70% of the original lens focus) and display these images at the same spatial angle as the image of the original single lens with a longer focal length, so the front surface of the two lenses is smaller than that of the original lens with a longer focal length. The second idea takes this into account. It is known that the cross-section of the light beam can be reduced by increasing its divergence. Thus, if we divide the light beam into two with less divergence, the cross-sections in these beams can be reduced by increasing their divergence to the divergence of the original beam.

By working together these two ideas, it is possible to effectively reduce and more curvature the output surface of the dioptric light optics of the display point powered by a group of LED crystals. Structurally, these ideas can be combined and realized, for example, as follows. Divide the light guide rod behind its input surface so that each arm receives a proportion of the light from the LED light beams (we simply optically pick up the LED light and cut it into smaller beams). The first part of each arm behind the input dividing node of the light guide rod is formed into a light scoop and concentrator (operating on the principle of total reflection), which will have a smaller cross-section at the output than at its input. The output reduced cross-section from the light-collecting and light-concentrating portions of each arm of the light guide rod is drawn into the focal plane of the reduced output lens, and the individual reduced output lenses are grouped as close together as possible.

Due to the principle of guiding the light inside the light-guide rod (by multiple total reflections of light from the side walls at different angles), it is uniformly mixed (homogenized) after a certain distance. In the elongated part of the light guide arm of the rod, in the part between the exit of the convex concentrator and the focus of the lens, there is effective mixing and homogenization of the light from the LED crystals. In the case of a multi-arm light guide, the minimum length required to homogenize the light is shorter than it would be in the case of a single arm with a larger cross-section. This is due both to the smaller cross-section (thereby causing more reflections per unit length) of the arm of the multi-light conducting rod, but also to the subsequent composition of the output light beams (cones) from the individual lenses into one resulting light beam perceived by the viewer.

According to the present invention, the problem of reducing the exit surface of the lens and increasing its curvature is solved as follows. Each arm of the light guide rod has two portions, a wider convex portion facing its entrance surface to the LED-crystal light source and the adjacent narrower prism portion facing the connecting lens. Each convex portion and the prismatic portion have four outer edges defining the outer upper and lower walls and two opposite side walls. The prismatic portion of the light-guide rod has a rectangular inlet cross-section that immediately follows the outlet cross-section of the convex portion. The two-arm light guide rod has an exit area in each arm of less than 63% of the light guide rod entry area facing the light source.

Further, it is preferred that the light guide rod is provided in at least one of its arms with at least one longitudinal slot which is guided by the convex portion and the adjacent prismatic portion, which parallel to the XZ plane with a minimum width greater than 0.2 mm. The minimum width of the slot ensures its effective functionality even in humid environments. Very efficient homogenization of light occurs especially in the elongated prismatic portion of the light guide, behind the convex concentrator, so that if at least in this part of the light guide there is a longitudinal slit or more slits, these slits actually increase the number of reflections of the light rays from the side walls. allows shortening the length of the light guide rod.

In terms of constructional arrangement, it is possible to choose variants where the connecting lens forms one non-detachable unit with the light-guide rod or its part, or vice versa, when the light-guide rod is

Separately detachable from the adjoining exit lens. The advantage of the detachable lens from the light guide rod is the simpler production of the opalescent cavity and the ability to vary the divergence of the radiating light beam by simply replacing the lens with a lens of another optical power.

Further, when the light guide rod is assembled from at least two separable units such as a convex portion and a prismatic portion, it is another advantageous alternative to changing the divergence of the radiating light beam by replacing the prismatic portion.

The LED crystals of the light source may be situated in a single housing or on a printed circuit board, and are grouped together in a single cluster with spacing greater than three times the largest dimension of the LED crystal. The minimal technological spacing of LED crystals leads to minimal cross-sections and dimensions of the light guide rod.

The LED crystals of the light source may be situated in a single housing or on a printed circuit board, arranged in one or two parallel lines with spacing not greater than three times the largest dimension of the LED crystal. The arrangement of LED crystals in a straight line offers the specific possibility of simply minimizing one cross-sectional dimension of the light-guide rod and minimizing the other cross-sectional dimension by branching in the plane of the straight line.

The LEDs of the light source may be encapsulated on the printed circuit board by a light guide rod or a detachable portion thereof. This reduces the overall cost of manufacturing the LED housing.

Clarification of drawings

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an axonometric side view of a partial longitudinal sectional view of a convergent optic light collector and color light mixer in the embodiment of a single-arm light-guide bar with an opalescent cavity and a lens Fig. 2 is a longitudinal cross-sectional view of a convergent optic light collector and mixer with a single-arm light-guide rod with opalescent cavity and a coupling lens; Fig. 3 an axonometric side view of a convergent optic optical collector and mixer with a single-arm light-conductor rod slit.

Fig. 4 is a light guide and color light mixer with convergent optics in a dual-arm light guide design in axonometric front view, Fig. 5 is a light guide and color light mixer with convergent optics in a dual-arm light guide design in axonometric side view, and Fig. 6 axonometric side view A view of the light guide and color light mixer with convergent optics in a two-arm light guide with longitudinal slot in each light guide arm.

DETAILED DESCRIPTION OF THE INVENTION

Example 1 (Fig. 1,2,3)

The technologically advantageous construction of the invention is described in more detail herein on a single-arm light guide bar 100 with numerical references to Figures 1, 2 and 3, wherein the individual numbers in the figures represent individual parts of the invention.

-4GB 307029 B6

The LED crystals 2 in the light source i are aligned in a straight line parallel to the Y axis (horizontal for transport equipment) and are covered (encapsulated) for a light transmissive drop of epoxy resin, urethane, cyanoacrylate, polyester or silicone based blend. Encapsulation of crystals has its optical justification. The materials from which the LED crystals are made have a relatively high refractive index and a large portion of the emitted light in the crystal would be reflected by total reflection back at their planar interface with air, so it is advantageous to encapsulate (drip) LED crystals with higher refractive index. than the air and the crystal then leaves more light. LED crystals can emit light of different colors, for example, in the case of three LED crystals for full color displays, it can be red with a dominant wavelength of about 625 nm, green with a dominant wavelength of about 528 nm and blue with a dominant wavelength of about 470 nm.

The single-arm light guide 100 and the coupling lens 120 are made of an optically transparent material such as glass, plastic, and the like. The walls of the single arm light guide 100 are smooth and allow for total total light reflection with minimal scattering. The shape of the single-arm light-guide bar 100 is comprised of a wider, convex portion 61 and a narrower prismatic portion 71. To reduce the overall length of the single-arm light-guide bar 100, the bar may have a longitudinal slot 73 (shown in FIG. 3). XZ and applied over the convex portion 61 and the prismatic portion 71, with a minimum width greater than 0.2 mm. The side walls of the single-arm light guide 100 are parallel planes to the XZ plane, as in the figures, or they may wedge toward the bond lens 120. Similarly, the upper and lower walls of the prismatic portion 71 of the single-arm light guide bar 100 may wedge toward the bond lens 120.

The convex portion 61 of the single arm light guide bar 100 functions as a light-gathering concentrator that concentrates light from the entrance surface 51 into a rectangular cross section 76. In the single arm light guide bar 100 with concentrator 61, the effect of reducing the exit surface 86 of the lens 120 is negligible. Therefore, to guarantee a substantial reduction in daylight disturbing reflections, it is advantageous to insert a smooth opalescent cavity 115 between the exit surface 108 of the single-arm light guide 100 and the exit surface 86 of the lens 120 that changes total reflection or refraction of daylight passage within the optical system. in Figure 2.

The opalescent cavity 115 deflects the rays of daylight 333 (dotted lines are deflected rays) outside the exit surface 108 of the single-arm light guide 100, so that the interfering light cannot be reflected, after reflection or scattering, on shiny, semi-matt or diffuse portions of light source 1 sec. The LEDs 2 return the light guide bar 100 to the viewer's field of view. Depending on the size and shape of the opalescent cavity 115, there will be a decrease in light output at the exit 86 of the lens 120, but this will not exceed twenty percent even in cavities comparable in size to the exit surface 108 of the single arm light guide 100. decrease in light intensity of disturbing reflections in the field of view of the observer. Opalescent cavities 115 are highly effective with a deflection p from the vertical plane YZ greater than 9 ° and a thickness d greater than 0.3 mm. The surface of the opalescent cavity 115 has a minimum size of 72% of the smaller dimension of the exit surface 108 of the light guide bar 100 when projected onto the YZ plane. The projection of the surface of the opalescent cavity 115 into the YZ plane may have a rectangular contour as with opalescent cavity 115 in Figure 1. or it may be elliptical. The upper edge of the opalescent cavity 115 is situated above the optical axis 200 of the lens 120. The smallest dimension of the opalescent cavity 115 is its thickness d, which is either constant over its entire surface, or may wedge or increase along the + Z axis.

In a particular embodiment, the exit surface 86 of the lens 120 may be elliptical, aspherical or bicononic. The traffic sign lens 120 has an optical axis 200 that is parallel to the + X axis, vertically displaced to the lower edge of the cross-section of the exit surface 108. The lower edge is an edge below in the + Z direction; the + Z axis points from the road surface towards the sky.

-5GB 307029 B6

Example 2 (Figs. 4, 5, 6)

Also contemplated is an alternative, although technologically more complex, but advantageous construction of the invention, wherein the light guide rod 10 is a two-armed, as in Figures 4, 5 and 6. In this embodiment, LED crystals 2 in the light source are also aligned in a single line. parallel to the Z axis, which is the vertical for transport equipment. In this particular case of the multi-arm light guide rod, the two arms are arranged one above the other along the Z axis, and the opalescent cavity 115 is in at least one of the two arms, i.e. in the upper, lower, or both. A substantially smaller or larger opalescent cavity 115 (not shown in FIGS. 4, 5, 6) between the focus and the exit surface 46, 47 of the twin lens 40 deflecting less or more daylight is beneficial to use dual arm light guide 10 on each arm LED crystals 2 have sufficient light output.

The two-arm light guide rod 10 has an entrance surface 11 facing the light source 1 with LED crystals 2, similarly to the previous exemplary embodiment. In this embodiment, the entrance surface 11 is connected to the crotch 12, from which two arms of the two-arm light guide rod 10, an upper and a lower arm, extend. Each arm carries a wider convex portion 21, 22 extending into a narrower prismatic portion 31, 32 terminated by an exit surface 38, 39 recessed into an output diopter, which is formed as a lens 40 of the two exit surfaces 46 and 47.

The input area H. and the crotch distance 12 of the two arms of the light-receiving concentrators of the convex portions 21 and 22 have parameters such that approximately the same (± 25%) amount of light from each LED crystal 2 in the light source 1 is emitted to each concentrator 21, 22. .

The side walls of the double-arm light guide 10 are parallel planes to the XZ plane. The cross-section of the entrance surface 11 of the light-guide rod 10 is reduced in the Z-axis direction of the concentrators 21 and 22 to their outlet cross-sections 36 and 37, in this case rectangular. The cross-sections 36 and 37 are immediately followed by the prismatic portions 31 and 32 of the light guide rod in which the light distribution from the cross-sections 36 and 37 is transmitted, blended and homogenized to the exit cross-sections 38 and 39 lying around the foci of the exit lenses. longitudinal through slits 33 and 34 (shown only in Figure 6) located in the convex portions 21, 22 and the prismatic portions 32, 33 help to minimize the length of the prismatic portions 31 and 32. as on all other side walls of the two-arm light-guide rod 10.

The exit surfaces 46, 47 of the twin lens 40 may again be elliptical, aspherical or bikonic in a particular embodiment, as is the exit surface 108 of the single arm light guide 100. The exit surfaces 46 and 47 of the twin lens 40 in the traffic sign design have optical axes 200 parallel to the + X axis) vertically displaced to the lower edge of the exit cross-sections 38 and 39 (the lower edge being the lower one in the + Z direction; the + Z axis pointing away from the road surface towards the sky).

The aforementioned constructions of the invention, used as individual light points (pixels) on the surface of variable traffic signs and traffic information devices, are assembled in a matrix arrangement or in a grouping into shapes of individual symbols.

The construction of the invention can also be used as a stand-alone powerful light source if the miniature LED crystals 2 are replaced by larger and larger quantities.

Said exemplary embodiments do not limit other possible alternative embodiments within the scope of the claims of the present invention.

-6GB 307029 B6

Industrial applicability

The best application finds the present invention on variable signage matrix plates on major city roads or highway junctions and on trailer labels where symbols and messages can be freely programmed depending on road traffic near work zones, sporting events, accidents , disasters and other temporary changes in road traffic. It can also be used in rail, water or air transport. The construction of the invention can also be suitably used in industrial and residential lighting technology.

Claims (16)

PATENT CLAIMS A light-guide and color-convertor with convergent optics, comprising a light source (1) with several LED crystals (2) with a common output surface for LED crystal light (2), directly connected to the optical input of a light-guide rod with at least one output a light area, and one focal lens adjacent each individual light guide exit, characterized in that between the at least one light guide exit surface (38, 39; 108) and the exit surface (46; 47); 86) the at least one opalescent cavity (115) is disposed from the plane perpendicular to the optical axis (200) of the exit surface (46, 47; 86) of the lens (40; 120) by an angle ( β) of at least 6 °, having a minimum thickness (d) of more than 0.2 mm in the direction of the optical axis (200) of the exit surface (46, 47; 86) of the lens (40; 120) and having an upper edge situated above are (200) exit surfaces (46, 47; 86) of the lens (40; 120). A convergent optic color light collector and mixer according to claim 1, characterized in that each individual output surface (46, 47; 86) of the lens (40; 120) has an optical axis (200) vertically displaced to the lower edge of the individual lens. exit surfaces (38, 39; 108) of the light guide rod (10; 100). The convergent optic optic color light collector and mixer according to claim 1, characterized in that the thickness (d) of the opalescent cavity (115) is constant over the entire cross-section of the opalescent cavity (115). The convergent optic optic color light collector and mixer according to claim 1, characterized in that the thickness (d) of the opalescent cavity (115) is wedge-shaped or tapered along the axis direction (+ Z). The convergent optic color light collector and mixer according to claim 1, characterized in that the light guide rod is designed as a single-arm light guide rod (100) with one arm or a two-arm light guide rod (10) with two arms. The convergent optic color light collector and mixer according to claim 1, characterized in that each arm of the light guide rod (10; 100) has two parts: a wider convex portion (21, 22; 61) whose entry surface ( 11; 51) facing the light source (1) with LED crystals (2) and a narrower prism (31, 32; 71) whose output face (38, 39; 108) faces the lens (40; 120) wherein each convex portion (21, 22; 61) and the prismatic portion (31, 32; 71) have four outer edges defining the outer upper and lower walls and two opposite side walls. The convergent optic color light collector and color light mixer according to claim 6, characterized in that the prismatic portion (31, 32; 71) of the light guide rod (10; 100) has A rectangular inlet cross-section (36, 37; 76) which immediately follows the outlet cross-section of the convex portion (21, 22; 61). A convergent optic color light collector and mixer according to claim 5, characterized in that the two-arm light guide rod (10) has an individual exit surface (38, 39) in each arm of less than 63% of the entrance surface (11) facing the light sources (1). The convergent optic color light collector and mixer according to claim 5, characterized in that the light guide rod (10, 100) is provided in at least one of its arms with at least one longitudinal slot (33, 34; 73) which is guided in a convex shape. part (21, 22; 61) and the adjacent prismatic part (31, 32; 71) and is parallel to the plane (XZ) with a width (s) of greater than 0.2 mm. The convergent optic optic color light collector and mixer according to claim 1, characterized in that the output coupling lens (40; 120) forms an integral part with the light guide rod (10; 100) or a part thereof. The convergent optic photocell collector and color light mixer according to claim 1, wherein the light guide rod (10; 100) is separately separable from the downstream output coupling lens (40; 120). A convergent optic color light collector and mixer according to claim 1, characterized in that the light guide rod (10; 100) is composed of at least two separable units, such as a convex portion (21, 22; 61) and a prismatic. part (31, 32; 71). The convergent optic color light collector and mixer according to claim 5, characterized in that the single-arm light guide rod (100) is free of the convex portion (61) and the cross-section of the entrance surface (76) of the prismatic portion (71) immediately adjoins the exit surface. light source (1). The convergent optic color light collector and mixer according to claim 1, characterized in that the LED crystals (2) of the light source (1) are situated in a single housing or on a printed circuit board and are grouped together in a single cluster with spacing to one another. not more than three times the largest LED crystal size. A convergent optic color light collector and mixer according to claim 1, characterized in that the LED crystals (2) of the light source (1) are situated in one housing or on a printed circuit board, arranged in one or two parallel lines. with spacing not greater than three times the largest LED crystal size. A convergent optic color light collector and mixer according to claim 1 or 5, characterized in that the LED crystals (2) of the light source (1) are encapsulated on the printed circuit board by a light guide rod (10; 100) or a detachable part thereof.