RU1778434C - Light reflector - Google Patents

Abstract

The invention relates to the construction of a lighting reflector and may find application in traffic signal lights and traffic lights. The purpose of the invention is to increase the reflector efficiency. The reflector consists of total internal reflection prisms made on a common carrier layer, has a front surface 1 formed by input 3 and output 4 refractive faces, and a rear surface 2 formed by 6 full internal reflection faces at angles close to the limiting and connecting faces 5. In the main embodiment of the design of the reflector and the light-signaling devices in which it is used, faces 5 are parallel to the faces 4 and illuminating the reflector of the rays 7, and faces 3 and 6 are arranged so that the 8 Frenets evskogo reflection rays 7 from the faces parallel to the main stream 3 7 rays undergoing sequentially refraction, reflection and refraction on the faces of the 3, 6 and 4, respectively. The use of a reflector provides high contrast light signals in the daytime and the absence of glare in the dark. 2 s. f-ly, 3 ill. C) VI VI 00 N CO CRi / i.

Description

FIELD OF THE INVENTION The invention relates to optics and can be used in directional lighting devices, in particular, in traffic lights and at traffic lights.

The purpose of the invention is to increase the efficiency of the reflector by increasing the coefficient of use of the light flux of the radiation incident on the reflector at reflection angles close to the limiting angle of total internal reflection.

In FIG. 1 shows the profile of the reflector and the path of the rays in it with optimal use; in FIG. 2 - reflector with a conical bearing layer used in a contrast lamp; in FIG. 3 is a reflector with a flat carrier layer used to increase the luminous surface and reduce the (blind) average overall brightness of the flashlight.

A reflector, the profile of which is shown in FIG. 1, is a solid-pressed part of a transparent optical plastic of arbitrary color, having a front refractive surface 1 and a rear reflective surface 2. The front surface 1 consists of input 3 and output 4 refractive faces, the back surface 2 is made of connecting faces 5 and faces b of total internal reflection. Facets 3 and 4 of surface 1, as well as faces 5 and 6 of surface 2, form, intersecting, obtuse concave and convex dihedral angles. The acute angle between faces 5 and 4 is always less than between faces 5 and 3, in particular, it can be zero; the acute angle between faces 6 and 3 is less than the acute angle between faces 6 and 4.

The following options are preferred.

Option 1: faces 5 and 4 are parallel.

Option 2: angles r and 9 satisfy the equation

fn sin (y - g)) cos (v + g)

Јnsin (y-0) cos2 (0 + J7). (1)

where n is the refractive index of the reflector material, and the parameter y, which has the meaning of the angle of incidence (and reflection) of the light beam from face 6, if it falls on the input face 3 parallel to the output face 4, lies within

45 ° at arcsin

1

(2)

In particular, it is possible to choose the parameter y equal to the limiting angle of total internal reflection

arcsin -.

(3)

Options 1 and 2 can be combined in one reflector, which is displayed on

FIG. 1.

The parallelism of faces 5 and A is optimal from the point of view of the translucency of the reflector in the rays of external illumination, but it can be violated, for example, in favor of

further reducing material consumption.

The implementation of equation (1) provides when illuminating the reflector in a direction parallel to the output faces 4,

reflection from faces 3 (Fresnel) in the direction strictly parallel to the rays that have undergone successive refraction, reflection and refraction on faces x 3,

6 and 4, respectively (angle $ in FIG. 1). In violation of relations (1) and the same

direction of illumination angle f} p, but

the difference (y)) may remain within the effective scattering angle of the device in which the reflector is used.

In the particular case of the refractive index, 5 relations (1) and (3) are satisfied

at at 24.4 °, t) 7.3 °, at 41.8 °.

The matching of the apertures of the faces 3, 6, 4 is determined in addition to the angles rj and in the relative position and relative sizes of these faces. The working area of the reflecting face 6 when illuminating the input face 3 along its entire surface parallel to the output face 4 is the base of an isosceles triangle with an angle of 2y at the vertex located at the intersection of faces 3 and 4 and is equal to 2tg y d, where d is the height of the triangle (Fig. . 1). Working area of the input face 3

(for the specified direction of illumination) coincides with the full width of the face 3 and is equal to a-. p / v - and: Work zone exit - p cos y t)

face 4 b.co82 () and can

make up only part of the total width S of the edge 4, with the connecting edge 5 parallel to the edge 4.

In optimal use, i.e. when illuminated in parallel with faces 4, a reflector whose profile satisfies equation (1). works as follows. The rays 7 are refracted by the faces 3, reflected at an angle near the faces 6 and, having refracted on the faces 4, exit at an angle p 2 (b + m}) to the original direction. In the same direction (p is ray 8, which experienced a Fresnel reflection from face 3, which therefore cannot qualify as loss.

When using a reflector in the indicated mode, the integral reflection coefficient, due to the 100% use of the light flux and the elimination of Fresnel losses on faces x 3 and their reduction on faces x 4, reaches 95% in the case of a sufficiently transparent material.

In FIG. 2 and 3 are schematic diagrams of devices in which a reflector is used. Depicted in FIG. 2, the light-signaling device with axis 00 contains a light source 9 in its focus F, an annular collecting lens 10 with the same focus F and an optical axis FQ passing at an angle p to its axis of symmetry 00 and the proposed reflector 11, made on a conical carrier layer so that its output faces 4 are parallel to the optical axis of the FQ lens. The reflector 11 directs the rays 7 and 8 of the source 9, refracted by the lens 10 and reflected by the faces 6 and 3, respectively, parallel to the axis 00 of the device. The rays of external illumination 12, incident at large angles to the bearing surface of the reflector 11, shine through the black housing 13 of the device; light rays 12 incident at small angles are reflected towards the blind hole in the reflector and are also absorbed by the walls of the housing 13. Thus, the phantom effect is eliminated and the contrast of the signals is improved.

In the apparatus of FIG. 2, the area of the reflector (and the outlet of the device) is minimized by the fact that the width of the working area of each outlet face 4 is equal to the total width of this face. In contrast, in the device of FIG. 3, it is possible to unlimitedly increase the distance between adjacent reflective faces 6 by increasing the connecting faces 5 and non-working sections of the faces 4 without loss of light on them, thereby reducing the average overall brightness of the outlet (combined with diffuser 14) of the device compared to the brightness of the collimator 10 illuminating the reflector 11. Here, the aim is to reduce the blind effect of the light signal device at small observation distances without affecting the visibility of signals from far ssto Nij. The reflector 11 of FIG. 3 executed on

it is a flat carrier layer and has the form of a right-angled coal plate whose width is equal to the diameter of the collimator 10 and the length is arbitrarily large due to the faces 5. Small prismatic angles (/ and 0) of the proposed reflector make it possible to reduce the glare of the external illumination (by rays 12). thereby improving daylight recognition.

0 The lighting reflector combines a number of useful properties, which in known (mainly catadioptric) reflectors can be realized only individually, 5 a high reflectance of the light flux, which can be used to increase the efficiency of lighting devices;

the possibility of a substantial increase in the transverse dimensions of the light beam, which can be used to increase the light opening of the device while reducing its dazzling brightness without reducing the light intensity (Fig. 3);

5 translucency in the rays of external illumination, which simplifies the design of anti-phantom light devices (Fig. 2,; 3);

small material consumption per unit of reflector area and manufacturability made of plastic (due to the small protrusions above the average level of the carrier layer) ensure the cost-effectiveness of the product in production.

5

Claims (3)

1. Lighting reflector made in the form of an optical element made of a transparent material, including a front refractive surface, consisting of alternating input and output faces, forming obtuse angles between themselves, and a rear surface of total internal reflection, different 5 in that, in order to increase the efficiency, the back surface of the reflector is made stepped in the form of alternating reflective and connecting faces, while the connecting faces form an angle with the input faces more than the output ones, and the number of reflective faces coincides with the number of input faces of the front surface. 2. The reflector according to claim 1, with the exception of 5 and with the fact that the connecting faces are parallel to the output faces. 3. Reflector 1 and 2, characterized in that the angles between the faces satisfy the following equations rj and b are the angles formed by reflecting faces with input and output faces, respectively; y is a constant defined by the inequality where n is the refractive index of the material with a 5th reflector; n sin (y -;) - cos (O-bc); n sln (y-0) cos2 (0-f t /), 45 ° at arcsln -. y- constant, defined 5th 45 ° at arcsln -.  n and