Portable device for control and measuring alternate-reflecting ability of light-returning articles

FIELD: the invention refers to optical measuring technique.

SUBSTANCE: the portable device for measuring of power of alternate-reflecting light designed for control of quality of light-reflecting articles has a source of light in a light-proof body for lighting of light-returning sample, an arrangement for stationing the sample under a given angle of lighting, a photo receiver for receiving alternate-reflective radiation and a half-transmitting mirror providing coordination of spatially dispersed channels of radiation and photo-receiving with the channel of lighting-reflective sample. The input opening of the photo receiver is fulfilled on a removable light-tight screen and its zones of light transmission are displaced from the axle of the photo receiver on a distance proportional to the required angle of divergence. At that a collecting lens is located between the screen and a light-sensitive element of the photo receiver.

EFFECT: increases accuracy of measuring.

3 cl, 6 dwg

The invention relates to the field of opto-mechanical and electronic instrumentation and can be used in devices for measuring and control of back-reflectivity of the road information signs and road button lights.

The level of technology

Known installation RETRO 1000 (and RETRO 2000, see [1], p.15 implemented in accordance with the scheme of [2], p.7, figure 3) to measure the back-reflectance (in another terminology, a "reflective" ability, or "factor svetovozvrascheniya" R, proportional to the ratio of the power I light back-reflected "cat's-eye" in this area (close to the direction of the light) to the value of its luminance: R˜I/E) retroreflective materials and products at given angles of divergence and lighting β (another frequent name divergence angle "angle", α is the angle between the direction of back-reflected (or "returned") beam and the direction is strictly the opposite of the incident beam, the normalized angles are very small, but, as a rule, is not equal to zero, because even when observed from the side of the light source, the photodetector (the eye of the observer - the driver of the car) and the source (headlight of the vehicle) do not coincide. Typical regulatory requirements (see GOST R 50577-93, Appendix G) shall apply to the corners, over the statement ("observations"), 0°12', 0°20', 1°30'. Lighting angle β characterizes the orientation of the reflective surface relative to the direction of light: β - the acute angle between the incident beam and the normal to this surface. The coefficient of svetovozvrascheniya as a function of these angles R(α, β) for good button lights very quickly decreases with α from 0 to 2° and slow - growth βproviding visibility retroreflective information signs in the back-reflected rays up to angles of light β about 45° and more), consisting of 1) a light source that generates directional (test specimen) radiation, 2) device (e.g., goniometer) for basing the test sample under a given illumination angle βremote on a large (10 m or more) distance L (base photometric measurements) from the source, 3) sensor return radiation that is located in the same plane as the source (normal to the direction of radiation) written on a small distance r≪L from the source. In terms of the following descriptions of the prototype and the claimed device in this device is the analog of optical channels radiation" and "important aspect" almost aligned with the main channel of the light-reflection" of the sample, the axis of which passes through the geometric center of the frame (aperture) of the sample, the OTF is nichiwa of incident luminous flux of the source (the presence in the premises of the other light sources is unacceptable). Set small (of the order of 0.3°) the divergence angle α ensures a certain offset value (value of r) of the center of the inlet of the photodetector from the axis of the main channel: a≈r/L. This setup requires a large, protected from external light space, while the sensitivity of the important aspect of small.

The well-known scheme of the portable device (see [3], p.4, figure 3) to control button lights in which to increase photosignal at a given angle of divergence used to ring the photocell mean radius of r≈α·L, covering the common axis of the channel, radiation, light-reflection and important aspect (passing through a Central hole in the cell), and the source is located behind the solar cell. The output of the device has a collecting lens that provides a constant illumination angle β over the sample area with a shorter base length L. the Disadvantage is the constant divergence angle α (to change it you need to replace the photocell complex shape), and the dimensions of the portable device is technically difficult for the scheme to provide value αless than 1° (no junction channels radiation and the important aspect is not possible to realize a sufficiently small values of r).

Known to be used as a prototype korotkobaznaya (hence, brightneedle development of the portable device) scheme Novikov (see [3], p.5, 7), also including the light source device based sample and the photodetector, and, in addition, the beam splitting device (beam splitter), which provides spatial separation channels radiation and important aspect of optical and coordination with the main channel of the illumination-reflectance of the test sample. The device is protected from external exposure) total light-tight enclosure. Optic radiation and important aspect intersect at a right angle, and the beam splitter is used semitransparent mirror, and the distance from the center of the mirror to the source and to the photodetector is equal to the same value of L₀, in which the sum of length L₁between the mirror and the test sample provides the basis electrophoretic L=L₀+L₁. The scheme provides a measurement of back-reflectance when the angle of divergence α≈0, but it does not allow for the possibility of measurements at more important (from the point of view informative back-and-reflecting devices) values of the angle α small, but not equal to 0, and there is no possibility of control angle α.

Prerequisites improvements

The purpose of the invention: increasing the accuracy of back-reflectivity of the light reflective products portable (korotkobaznaya protected from external light) models of the device is ay more accurate selection of the total reflected flux) rays back-reflected under predetermined angles of divergence and increase the level of functionality (wider range of performance parameters) for by providing reconfiguration of the device at various angles of divergence.

The invention

The objective is achieved in a device for measurement and control of back-reflectance samples of retroreflective materials and products with a common light-tight housing containing 1) channel radiation, including light source, 2) the channel of the light-reflection ("main channel"), including device-based test sample of the product, 3) the important aspect of channel, including the sensor, and 4) the beam splitting device ("beam splitter"), for example, in the form of a semitransparent mirror, which is placed at the intersection of the axes of these channels, at the same distance from the outlet of the source and the inlet of the photodetector and provides spatial separation (spatial separation) radiation and important aspect of optical and coordination with the main channel of the light-reflection (so that the axis of one - any - channel radiation and important aspect is the geometric extension of the main channel, and another axis coincides with the mirror image of the first), characterized in that the inlet of the photodetector made in the form of light transmitting areas on a separate removable or movable - opaque screen between the screen and the photosensitive element fotop is amnike (small photocell or photomultiplier) coaxially with the element placed collecting short-focus lens, and the light transmitting area is offset from the axis of the important aspect for a distance proportional to the desired angle of divergence (the overall axis of the lens and photocell and the axis of the important aspect can be the same or may not be the same).

The entrance aperture of the photodetector can be made in the form of an arc, in particular annular, slotted, the center of curvature of which lies on the axis of the important aspect (which, as an additional effect, can significantly increase the sensitivity of measurements by increasing the area of the inlet opening).

The device is equipped with an additional control channel, the axis of which spatially coincides with the position of the mirror image of the axis of the main channel (channel lighting-reflection), while in the case of the device on the axis of the control channel is made additional observation hole.

List of drawings

The invention is illustrated by drawings. Figure 1 shows a variant of the optical system of the instrument as a whole. In figure 2, 3 - ways aperture of the light source and screen-aperture of the photodetector, respectively, and figure 4 - alignment of their images. Figure 5, 6 shows the options screen-aperture of the photodetector (with overlay image tag source), providing high sensitivity to weak reflexive reflection through integration of signals in different information-knowledge is imich directions of svetovozvrascheniya. Figs.4, 5, 6 indicate positions, not pointing to the real items and the pictures created by a translucent mirror, underlined, for example, while the inlet of the receiver is marked "15", his image - "15".

Information confirming the possibility of carrying out the invention, and the operation of the device

The device (1) contains a light-tight housing 1 of the following units and elements: the unit of the light source 2 with a conditional point O_andin the plane of its discharge opening; a device-based, which is the plane of the main light holes 3 in the housing 1 with conditional centre, covered with protective glass or a lens 4, and the adjacent (operable unit) to the subject of back-reflecting pattern 5; block of the photodetector 6 with conditional point O_fin the plane of its inlets. In the centre Of_Csystem for spatial isolation channel radiation O_and-O_Cand channel important aspect of O_C-O_fand optical coordinating with the main channel of the light-reflection About_C-Posted by the beam splitting device 7 in the form of a semitransparent mirror 8 or glued beam-splitting prism (In the case of manufacturing the beam splitter 7 in the form of a prism, you should consider some fracture (figure 1 not shown)that g is avna and the control axis of the instrument will undergo on the refracting faces of the prism, as these faces must be made with deviation from the normal (axial rays) provisions to ensure the reflection of the inevitable parasitic (Fresnel) reflection by the light-absorbing housing unit (i.e. away from the photodetector)!), containing flat translucent inner face of the mirror 8. The optimum reflectivity of the beam splitter is 50%.

In addition to the main hole 3, the housing 1 may be made auxiliary hole 9 with the center O', which during setup and adjustment of the device supplemented (outside) the Supervisory device 10 (a magnifying glass or eye tube), and in the operating mode can be overridden (from the inside) additional comparison photocell 11, and forms with the center O_Csystem control channel O_C-About'. The photodetector 6 and the comparison photocell 11 is connected to a common electronic display unit, which serves for reading (figure 1 not shown).

Normal to the plane of the main hole 3 - plane-based sample 5 forms an angle β with the axis O_Cequal to the desired angle of illumination of the sample 5. If you need to provide constant illumination angle β over the entire area of the sample hole 3 will need to override the collecting lens 4 with a focal length equal to L or (if for example a certain spread angle of the light relative value β) the big L.

Source block 2 includes either the aperture to the outlet opening 12 defined, often circular shape of diameter d_and; the center of the hole (figure 2) is on the axis O_C-O_and. Aperture is illuminated by an incandescent light bulb or other source with a compact luminous body 13. Lighting either directly (when the luminous body must be larger than the opening 12 of the diaphragm), or through a lens 14 that generates an image (enlarged about a/b, where a and b are distances from the lens to the luminous body and the diaphragm, respectively) of the body 13 near the aperture, covering its outlet 12. But the "outlet" of the source can be very luminous body or his image, if it is compact ("dot"). Aperture in this case is absent or replaced, to reduce stray light, black screen with hole 12, a large body of 13 (or its image).

The inlet 15 of the photodetector 6 round diameter d_f(3) or more complex forms (figure 4, 5) is performed on the opaque screen 16 that intersects the axis of the important aspect in the point O_fand its light transmitting areas distant from the point O_ffor a given value of r=α·L (where α in radians). This shift light hole 15 from the axis O_f-O_Cspecifying the dimensions of the screen 16 may be substantially larger than the dimensions of the light-sensitive the part of the receiver photocell 17. Therefore, directly behind the screen posted by collecting short-focus lens 18, and then near the image plane of the main holes 3 of the device produced by the lens 18 is itself light-sensitive element 17. The size of the photocell 17 is consistent with the image size of the hole 3 (coincident with the size of the luminous area of the sample 5): it should fit on the light-sensitive area of the photocell and can be many times (namely, L/f, where f is the focal length of the lens 18) less holes 3 of the device. Dimensions (diameter) of the lens 18 (screen 16) are consistent with the maximum value of the angle d (at the Central position of the point O_fthe diameter of the lens not less than the value 2α·L+d_f).

Position (relative to axis O_f-O_C), the shape and the size of the input svetopropusknaya holes 15 in the screen 16 sets the value of the divergence angle αa position of the observation plane (plane angle α) relative to the plane of light (plane angle βand the balance between the accuracy of the determination of the angle α and the sensitivity of the device. Appropriate selection of the position and shape of the light holes 15 (to which the screen may be removable), you can provide the measurement of back-reflectivity of the sample 5 with different values of angle α and in different planes angle α and (relatively pleskot the lighting angle β ), as well as integral performance (total return reflection in directions that meet almost the most important information values α).

For example, if the inlet sensor has the shape of an arc or even the ring slots with radius r and width h≤r/3 (figure 5), and the outlet 12 of the source (figure 2) is a round, diameter d_and˜h, and if the location of these elements in relation to the mirror 8 provides the alignment hole 12 and the image (in the mirror) arc (circular) holes 15 (this can be controlled while observing through hole 9), then the measurements will be integrated signal from the sample 5 in all planes of reflection with the values α=r/L±h/L, which significantly increases the sensitivity of measurement of the return reflection for a given angle of divergence by increasing the area of the inlet opening.

Figure 6 shows another variant of the translucent zone 15, which is extended in the radial direction from r1 to r2. Here γ - the angle between the plane b-b' lighting (sample 5) and the plane electrophoretic reflected rays (i.e. between the planes of angles β and α). The device measures in this case, a certain integral (largest α) characteristics of the sample 5, which simulates the most common situation in practice use is of retroreflective materials on the road (the driver of the vehicle observes in light of its high reflective informative sign. The angle α this is changing (decreasing) from the values of r2/L to r1/L; angle γ approximately characterizes the plane of observation).

On the front (facing the center O_Cside ) of the aperture of the source 2 may be caused visible (using the observation device 10) markup (crosshair), indicating the position of the point O_andfacilitating the alignment of the optical system of the device. The same applies to the diaphragm-screen 16 of the photodetector 6, its reference point O_fapplied most often (in particular, 1, 5, 6) in the center of the screen 16 on the axis of the photocell 17 and lens 18, but may be away from this axis (srig, 4, where the axis of the important aspect About_C-O_fdoes not coincide with the axis of the block elements 17 and 18 of the device), which allows to reduce the dimensions of the screen 16 (and the diameter of the lens 18) at a given angle α.

Setting the device to use for measurements at a given value of the divergence angle α is carried out using a control channel O'-O_Cin the following way. Open observation hole 9 and is extracted to the comparison photocell 11, overlying the hole, if there is one) and the main hole 3 (retroreflective sample is not required). Through the hole 3 by any extraneous light source (own source 2 is disabled) covers the internal components of the device, and (with the Supervisory condition the device 10) is controlled by the combination of image reference points About _andand O_fon the diaphragms of the source 2 and the photodetector 6, or rather the combination of one of the points About_andand O_fimage (created by the mirror 8) other (Fig.4-6). In the absence of combining it must be achieved or the necessary lateral displacement of one of the blocks 2 and 6, or a gradual change in the slope of the mirror 8 (at least one of these three options, the adjusted offset (least number of adverse side effects, from the point of view of the possible impact on the lighting conditions of the sample 5, it should be expected from the displacement unit 6) it is desirable to provide in a construction of the device in advance).

In operating mode, the 9 hole must be closed (against the penetration of external illumination), the comparison photocell 11 is installed in the control channel O'-O_Cthe main hole 3 is provided in contact with the test back-reflective sample 5, source 2 is turned on. The light source 2, breaking the beam splitting device 7, is divided into two beams, one of which is absorbed by the solar cell 11, the other at an angle lighting β falls on the sample 5, is experiencing a return reflection and, again overcoming a beam splitter 7, partially lost ("back" to the source 2), partially falls on the photodetector 6. Rays, "return" sample 5 at an angle of divergence αthat is configured device, pass through sweep the starting zone 15 screen 16, go collecting lens 18 on the photocell 7, create a photocurrent and form an electronic signal that the display is converted into information about back-reflectivity of the sample 5. The signal from photocell 11 comparison, proportional to the brightness of the source 2, corrects the result of measurements, depending on the possible instability of this brightness.

The effectiveness of the invention is to improve functionality and increase the accuracy of back-reflectance (ratio of svetovozvrascheniya) portable (korotkobaznaya, portable) circuits devices that is provided by the possibility of easy reconfiguration of the device at various angles of divergence due to the use of mobile in the transverse direction or (shift) of the diaphragm-screen sensor with offset from the center of the light hole and the elimination of uncertainty in the divergence angle due to the use of the control channel. An additional effect is to increase the sensitivity of the measurements by increasing the area of the inlet opening (for example, in the form of a ring), integrating the signals, back-reflected in different directions. Possible base electrophoretic L (it also defines the main dimensions of the device), in which the most useful application of the proposed scheme in then the exploring and portable devices from 0.3 m to 0.7 m But it is possible to apply the scheme in korotkobaznaya fixed installations up to 2-3 m, while the permissible angles of divergence α limited to reasonable (up to 10 cm) dimensions of the lens 18.

Sources of information

1. Brochure "LMT Photometers Colorimeters", 1998, Productinformation, p.15.

2. International Standard ISO 6742/2. Cycles - Lighting and retro-reflective devices - Photometric and physical requirements - Part 2: Retro-reflective devices, 1985, p.7, fig.3.

3. Abstract collection of "Automotive electrical equipment", no 2, 1967, p.1-6.

1. Portable device control and measurement of back-reflective retroreflective articles having common light-tight enclosure containing a channel radiation, comprising a source of light, channel light-reflection ("main channel"), including device-based test sample product, channel important aspect, which includes the photodetector and the beam splitting device ("beam splitter"), which lies at the intersection of the axes of these channels, at the same distance from the outlet of the source and the inlet of the photodetector and provides spatial separation channels radiation and important aspect of optical and coordination with the main channel, characterized in that order improve functionality, the entrance aperture of the photodetector made in the form of light transmitting areas on a separate opaque screen between the screen the nome and the photosensitive element of the photodetector aligned with the element placed collecting short-focus lens, and the light transmitting area is offset from the axis of the important aspect for a distance proportional to the desired angle of divergence.

2. The device according to claim 1, characterized in that, in order to increase sensitivity, the entrance aperture of the photodetector made in the form of an arc of the slot, the center of curvature of which lies on the axis of the channel of the important aspect.

3. The device according to claim 1 or 2, characterized in that, to increase the measurement accuracy, it is equipped with an additional control channel, the axis of which coincides with the image of the axis of the main channel in the mirror of the beam splitter, while in the case of the device on the axis of the control channel is made vantage point.