EP0413088A1 - Work lamp - Google Patents

Abstract

Work lamps such as those which are preferably employed in office system work places put high demands on a uniform illumination of the working surface without dazzling the user in the process. As shown in practice, the necessary screening of the fluorescent lamp arrangement leads to disturbing reflected images, particularly given a low lamp installation height. It is proposed to provide the fluorescent lamp arrangement (LL), which is located here at the rear side of the housing trough (G), with a flat main reflector (R1), which is inclined forwards and reaches as far as the front edge of the housing trough (G), and with an auxiliary reflector (R2) below and in front of the fluorescent lamp arrangement (LL), which makes it impossible to see into the fluorescent lamp arrangement (G). The light exit opening is covered in this arrangement by a diffusing panel which has a fine prismatic structure on the lamp side. <IMAGE>

Description

Technical field

The invention relates to a workstation lamp of low installation height, consisting of a flat box-shaped housing trough, which takes up a fluorescent lamp arrangement including light-directing and other electrical components and is closed at the top with a diffuser for the light emission, in which the one at the rear in a predetermined height fixed above the work table, extending in the longitudinal direction of the worktop housing pan with its top down against the work table and in which the fluorescent lamp assembly is a linear light strip extending over the length of the housing pan.

Underlying state of the art

Workplace lights of this type, as are known for example from the literature DE 26 30 556 A1, have the task of compensating for strong shadows from daylight and general lighting. Such workplace lights are of particular importance in "office system workplaces" in open-plan offices that have been common for some years, in which the individual spaces are partitioned off by partitions and are often provided with cupboard attachments above the rear part of the work surface.

The lighting technology requirements placed on such workplace luminaires are by no means limited to an even distribution of illuminance on the work surface. Rather, the Avoidance of structured light reflections.

As can be seen, the shielding of the fluorescent lamp arrangement on shiny visual objects causes structured reflex images, which make the visual task far more difficult (interference information) than unstructured, informationless reflexes. Furthermore, it is shown with such workplace lamps that the illuminance in the rear part of the work surface is significantly higher than in the front work area, which usually contains the work task. This draws attention away from the task at hand. In addition, in the case of such workplace lamps, as long as a vertical partition is provided on the back of the work table, inappropriately high luminance levels occur. This can cause distracting reflections on the work item or on display devices placed opposite the rear wall. The use of such workplace lights without the partition mentioned is not possible here, because otherwise severe glare will occur in people whose workplace is on the opposite side.

Disclosure of the invention

The invention has for its object to provide a solution for a workplace lamp of the type described in the introduction, which on the one hand largely avoids structured reflex images on the work item and furthermore reduces the undesirable high illuminance in the rear part of the work surface to such an extent that the use of such workplace lamps also in double workplaces with people sitting opposite each other without a vertical partition in between.

This object is achieved according to the invention by the features specified in claim 1.

Due to the special design and arrangement of main and Auxiliary reflector with good shielding of the fluorescent lamp arrangement, in addition to uniform illumination of the work table in its longitudinal extension, also prevents the undesired increased luminance on the back of the work table and, in addition, a strong reduction of structured reflection images is achieved by a suitable design of the diffusing screen.

The auxiliary reflector that shields the fluorescent lamp arrangement can be used according to claim 2 in an extremely advantageous manner by selecting its width projected onto the horizontal to determine the luminance at the rear of the work table.

In order to optimize the reduction of the undesired structured reflex images on the work surface by means of light control via the lens, it is proposed to divide the lens into a wide front area and a narrow rear area and at least the wide front area as a prismatic plate with parallel prisms in To design a fine structure on the light incidence side with prisms running perpendicular to the longitudinal extension of the work table. The width of the rear narrow strip area is chosen so large that the transition between the two strip areas is shielded by the auxiliary reflector or its angled foot against the light directly incident on the lens.

Additional preferred embodiments of the subject matter of the invention are specified in the further claims 4 to 17.

Brief description of the drawing

• Fig. 1 die Seitenansicht eines Bürosystem-Arbeitsplatzes mit rückseitiger Trennwand und Schrankaufsatz, bei dem die Arbeitsplatzleuchte in die Unterseite des Schrankauf­satzes eingebaut ist,
• Fig. 2 eine Aufsicht auf die Tischfläche des Arbeitsplatzes nach Fig. 1 mit Bereichen üblicher, durch die Abschir­mung der Leuchtstofflampenanordnung der Arbeitsplatz­leuchte bedingten strukturierten Reflexbildern,
• Fig. 3 eine schematische Explosionsdarstellung der erfindungs­gemäßen Arbeitsplatzleuchte,
• Fig. 4 eine Querschnittsdarstellung der Arbeitsplatzleuchte nach Fig. 3,
• Fig. 5 eine Aufsicht und eine Seitenansicht, der die Gehäuse­wanne der Arbeitsplatzleuchte nach den Figuren 3 und 4 abschließenden Streuscheibe,
• Fig. 6 ein Ausschnitt aus einer 45^o-Prismenrasterfolie, wie sie bei einer Streuscheibe nach Fig. 5 zur Anwendung kommt,
• Fig. 7 und 8 die Lichtlenkung und ihre Auswirkung auf die Herabsetzung von strukturierten Reflexbildern auf der Arbeitstischfläche erläuternde schematische Darstellungen,
• Fig. 9 und 10 weitere bevorzugte Gestaltungen der Strei­scheibe.

In the drawing, the figures used to explain the invention in more detail

• 1 is a side view of an office system workstation with a partition on the back and a cabinet attachment, in which the workplace lamp is installed in the underside of the cabinet attachment,
• 2 is a plan view of the table surface of the workplace according to FIG. 1 with areas of conventional structured reflex images caused by the shielding of the fluorescent lamp arrangement of the workplace lamp,
• 3 is a schematic exploded view of the workplace lamp according to the invention,
• 4 shows a cross-sectional view of the workplace lamp according to FIG. 3,
• 5 is a plan view and a side view of the diffusing screen that closes the housing trough of the workplace lamp according to FIGS. 3 and 4,
• Fig. 6 is a section from a 45 ^o -Prismenrasterfolie as it comes at a diffusion plate of FIG. 5 for use,
• 7 and 8 are schematic representations explaining the light control and its effect on the reduction of structured reflex images on the work surface,
• 9 and 10 further preferred designs of the streak disk.

Best way to carry out the invention

The work station AZ, which shows a side view of an office system work station, has a work table AT with a table height th = 730 mm, on the rear of which a vertical partition TW with a top cabinet AS is provided in a cabinet height sh = 500 mm above the work surface AF . The eye position AP of the user of this work station AZ is at an eye level ah = 400 mm above the work surface AF. The workplace lamp L with the fluorescent lamp arrangement LL, which is indicated in broken lines in FIG. 1, is built into the underside of the top cabinet AS.

The light LI of the workstation lamp L incident on the work surface AF, as is usually perceived at the predetermined eye position AP of the user, divides the work surface AF of the work table AT into three successive zones as viewed by the user, namely a zone of low light reflection intensity Z1 in the rear area of the work table AT, a zone of high light reflection intensity Z2, which adjoins this rear zone and a third zone without light reflections Z3 on the front of the work surface AF. These zones are shown in the plan view of the work surface AF shown in FIG. 2 with a usual width bt = 800 mm and a usual length lt = 1600 mm of such a work table AT. The zone of low light reflection intensity Z1 has a width of bz1 = 450 mm, the zone of high light reflection intensity Z2 a width of bz2 = 150 mm and the zone without light reflections Z3 a width of bz3 = 200 mm. The different intensity of the light reflections is indicated in Fig. 2 by larger and smaller nested circles.

As has already been stated, these usual intensities of the light reflections on the work surface AF result from the indispensable shielding of the fluorescent lamp arrangement LL of the work station lamp L. In FIG. 2 it is assumed that the work station lamp L extends over the entire length lt of the work table AT and that here the fluorescent lamp arrangement LL in the workplace lamp L is approximately adapted to this length.

The conventional reflection lamps of this type in addition to the structured reflection images on the work surface AF shown in FIG. 2 and the much too high luminance in the rear area of the work table AT and the partition wall TW can largely be achieved by the inventive workplace lamp shown in an exemplary embodiment in FIG. 3 reduce or eliminate.

3 consists of a housing trough G with a rear side wall G1 and a front side wall G2 in the direction of view of the workplace user. The housing trough G is closed by a diffuser SS, which is fastened to the housing trough G in a light-tight manner at its edges. The fluorescent lamp arrangement LL, which extends practically over the entire length of the housing trough G, which in the simplest case is a single fluorescent lamp of corresponding length, is arranged in the vicinity of the rear side wall G1. In front of the fluorescent lamp arrangement LL there is a planar main reflector R1 which extends over the entire length of the housing wall. 3 in FIG. 4, the main reflector R1 extends forward to the front side wall G2 of the housing trough G and is inclined toward this front side wall at a small angle α to the horizontal. With its rear edge R11 running parallel to the fluorescent lamp arrangement LL above the fluorescent lamp arrangement LL, the main reflector R1 ends at a distance b shown in FIG. 4 in front of the fluorescent lamp arrangement LL, which is chosen such that the far larger proportion of the light LI at the main reflector R1 is less than one Angle γ> 30 ^o to the vertical against the lens SS is deflected.

As FIGS. 3 and 4 also show, in addition to the main reflector R1, the workplace lamp L also has an auxiliary reflector R2 which also extends over the entire length of the housing trough G and is arranged here directly above the lens SS in front of and below the fluorescent lamp arrangement LL. The auxiliary reflector R2 has a width e projected onto the horizontal and is also inclined toward the diffuser SS at a small angle β. On the part of the fluorescent lamp arrangement LL, the auxiliary reflector R2 merges into an angular base R22 which extends rearward under the fluorescent lamp arrangement LL and serves primarily to shield the lamp light which falls directly onto the lens from above. The width c of the angle foot ßes R22, and the mentioned width e of the auxiliary reflector R2 are dimensioned so that the desired light distribution between the front and rear part of the work table is achieved. As can also be seen in FIG. 3, the main reflector R1 and auxiliary reflector R2 are delimited on both sides at right angles to this by triangular or trapezoidal, plane end reflectors R3. The front reflectors R3 extend rearward beyond the rear edge R11 of the main reflector R1.

This design of the overall reflector arrangement, as shown in FIG. 4, has the effect that the major part of the light LI emitted by the fluorescent lamp arrangement LL is deflected at a relatively large angle γ to the vertical at the main reflector against the lens SS, as a result of which the desired uniform and low-reflection image is deflected Illumination of the work surface AF of the work table AT is favored. By a suitable choice of the angle α within the limits of 10 ^o ≦ α ≦ 20 ^o , the ratio of the light emitted downwards at a large angle γ to the vertical by the diffusing screen SS to the light emitted at a small angle to the vertical can be adapted to different lighting requirements within certain limits will. In the same way, the angle of the inclination of the auxiliary reflector R2 against the horizontal can be selected within certain limits, preferably within the limits 5 ^{o o} β ≦ 15 ^o .

The main reflector R1, the auxiliary reflector R2 and the end reflectors R3 are usually made of anodized aluminum sheet. The auxiliary reflector expediently has a high-gloss mirror surface. As the light LI drawn in in the form of rays in FIG. 4 shows, the auxiliary reflector R2 not only shields the fluorescent lamp arrangement when the user is in the normal eye position AP, but also amplifies the light via a double reflection of the light at the auxiliary reflector R2 and at the main reflector R1 at a large angle γ to the vertical emitted light component.

In a first exemplary embodiment, a diffuser SS with the width g is shown in plan view and side view in FIG. 5. The diffusing screen SS is designed as a prismatic plate with parallel prisms in fine structure on the light incidence side and also divided into a front wide strip area SB1 with prisms running perpendicular to the longitudinal extension of the work table AT and a rear narrow strip area SB2 in the extension of the housing trough G. In this first exemplary embodiment, the rear narrow strip area SB2 is designed with prisms that are parallel to one another and have a fine structure on the light incidence side, which extends in width bt at an angle δ in the limits 20 ^o ≦ δ ≦ 40 ^o and in mirror image to the center line M when the work table AT extends of the narrow strip region SB2, which is subdivided in its length in the middle. The width f of the narrow stripe area SB2 is chosen so large that the transition between the two stripe areas SB1 and SB2 is shielded by the auxiliary reflector R2 or its angled base R22 against the light LI of the fluorescent lamp arrangement LL which is directly incident on the diffusing screen SS.

As the side view of the diffusion plate SS also shown in FIG. 5 indicates, it can consist of a carrier plate TP made of clear glass or a clear synthetic glass, for example acrylic glass, to which a commercially available prism film PF with the desired fine prism structure is adhered.

The fine prism structure preferably consists of a 45 ^o prism grid P, which is shown in the detail in FIG. 6. The fine structure of the 45 ^o -prism grid P has a grid width RB of 0.35 mm and a grid depth RT of 0.17 mm. Such a prism sheet is commercially available under the name 3M Scotch Optical Lighting Film.

Due to the design of the course of 45 ^o -Prismenrasters P of the rear narrow strip area SB2 at an angle δ to the center line M, the user is to look at the narrow directly above this strip area SB2 arranged Leuchtstofflam denied the pen arrangement and at the same time largely prevented the formation of structured reflex images in the zone designated Z1 in FIG. 2.

The reduction in reflection achieved by the alignment of the 45 ^o -Prismenrasters P in the wide strip area SB1 is explained in detail in the illustrations of FIGS. 7 and 8 The light LI emanating from the fluorescent lamp arrangement LL is directed in the direction transverse to the viewing direction of the user when passing through the diffusing screen SS and leads in the extension of the work table AT on the working surface AF to a central shielding area AB which is delimited on both sides by bright areas HB . In the shielding area AB, the diffusing screen SS has a transmittance of less than 10% and the light exit opening of the lamp appears in an almost structureless dark gray. Accordingly, the reflection image of the shielded area has no structure and its luminance is a factor of 1:80 below the luminance of the fluorescent lamp arrangement. In this way it is achieved that the reflection image is barely perceptible even on high-gloss materials under normal ambient conditions.

In the case of a work station AZ, as indicated as an exemplary embodiment in FIG. 1, a shielding area AB of a trapezoidal shape is very much obtained for the user's direction of gaze in accordance with the eye position AP, as the view of the working surface AF according to FIG. 8 shows low reflection luminance about the width of a DIN A4 page. According to FIG. 2, as shown in FIG. 8, for the zone of low light reflection intensity Z1, the zone of high light reflection intensity Z2 and the zone without light reflections Z3, luminances in the shielding area AB and in the zone Z1 are approximately 1:80 and in the bright areas HB the zone Z2 luminances of 1:20 compared to the luminance of the fluorescent lamp arrangement LL.

If the indicated direction of view is approximately maintained, The eye position AP can be changed as desired in the longitudinal direction of the working surface AF without the lighting conditions changing for the user because the low-reflection shielding area AB also moves.

As can also be seen in FIG. 7, the shielding area AB is illuminated without reflection by the light emerging laterally from the unshielded areas of the diffusing screen SS. The bright areas HB on both sides of the shielding area AB still have a reflection image, but due to the properties of the main reflector R1 and auxiliary reflector R2, the reflection image that occurs is unstructured and its luminance is, as indicated in FIG. 8, by at least a factor of 1 : 20 below the luminance of the fluorescent lamp arrangement LL, so that this results in only a slight complication of the visual task.

In the further preferred exemplary embodiments shown in FIGS. 9 and 10 for spreading discs in sandwich form, the prism film PF described in connection with FIG. 5 is clamped practically without adhesive between a clear glass plate representing the carrier plate TP and a cover TAP, likewise in the form of a clear glass plate. The clear glass plates are expediently plastic plates, for example made of acrylic glass or polycarbonate.

According to FIG. 5, the spreading disc SS is also subdivided in its extension into a front wide strip area SB1 and a rear narrow strip area SB2. In contrast to the embodiment according to FIG. 5, however, the rear narrow strip area SB2 on the light incidence side of the carrier plate TP is not designed with prisms that are parallel to one another in fine structure, but instead has a lacquer layer or a plastic film cover with a light transmittance of 5 to 10%.

The auxiliary reflector R2 is fastened by means of adhesive to the top of the cover TAP in such a way that the joint between the front wide strip area SB1 and the rear narrow strip area SB2 lies below the auxiliary reflector R2.

As can be seen from the embodiment of the diffusion plate SS according to FIG. 10, it differs from the embodiment according to FIG. 9 in that here the front wide strip area SB1 of the carrier plate TP extends into an elongated central strip area covered with the prism plate PF on the light incidence side SB11 and two short edge strip areas SB12 and SB13 is divided. The short edge strip areas SB12 and SB13 are covered on the light incidence side with a lacquer layer or a plastic film, which have a light transmittance of 10 to 20%.

The lacquer layers or plastic films in the area of the narrow rear stripe area SB2 and in the area of the short edge stripe areas SB12 and SB13 must be designed so that they appear structureless in transmitted light, i.e. have a uniform "cloud-free" pigmentation. Furthermore, the light transmission must be aselective, i.e. the light from the fluorescent lamp arrangement must not have a color cast after it has passed through the lacquer layer or the plastic film. A varnish or a plastic film in white, gray or silver color is useful.

In order to ensure that in the embodiment according to FIG. 10 no disturbing gaps occur in the transition area between the elongated central stripe area SB11 and the short edge stripe areas SB12 and SB13, it is expedient here to overlap the prismatic film PF with the lacquer layer or the plastic film cover from 5 mm.

It is for lighting workplaces where electrostatic sensitive devices are used It is advisable to provide acrylic glass or polycarbonate with a conductive coating as the carrier plate TP of the diffusing screen SS. Such material is commercially available, for example, under the name "ESLON DC-PLATE".

In this case, the carrier plate TP of the diffusing screen must then be treated on the edge side with a conductive "final coating liquid" and, moreover, a ground contact must be attached to the carrier plate by means of a conductive adhesive.

In a preferred embodiment of the workplace lamp for a workplace according to FIG. 1, the following dimensions result:
α = 10 ^o
β = 8 ^o
γ> 30 ^o
δ = 20 ^o
a = 12 mm
d = 26 mm
b = 42 mm
c = 12.5 mm
e = 38 mm
f = 35 mm
g = 240 mm
Prism grid film: "3M Scotch Optical Lighting Film (grid dimensions corresponding to FIG. 6).

Claims (17)

1.Workstation lamp of low installation height, consisting of a flat box-shaped housing trough, which takes up a fluorescent lamp arrangement including light-directing and other electrical components and is closed at the top with a diffuser for the light emission, in which the at the rear at a predetermined height above the Worktop fixed, extending in the longitudinal direction of the worktop housing pan is oriented with its top down against the work table and in which the fluorescent lamp arrangement is a linear light strip extending over the length of the housing pan,
characterized,
- That in front of the fluorescent lamp arrangement (LL), which is arranged in the direction of view to the rear of the work table (AT) in the rear area of the housing trough (G), a flat main reflector (R1) extending over the entire length up to the front side wall (G2) is provided which is inclined forward at a small angle α within the limits 10 ^o ≦ α ≦ 20 ^o to the horizontal and with its rear edge (R11) running parallel to the fluorescent lamp arrangement (LL) above the fluorescent lamp arrangement (LL) in such a large one Distance (b) in front of the fluorescent lamp arrangement (LL) ends that the far greater proportion of the light (LI) on the main reflector (R1) is deflected at an angle γ> 30 ^o to the vertical against the lens (SS) and
- That immediately before and below the fluorescent lamp assembly (LL) is also provided over the length of the housing trough (G) extending auxiliary reflector (R2), which is inclined at a small angle β in the limits 5 ^o ≦ β ≦ 15 ^o to the front and whose projected width (c + e) is greater than the distance (b) of the rear edge (R11) of the main reflector (R1) from the fluorescent lamp arrangement (LL). 2. workplace lamp according to claim 1,
characterized,
- That the auxiliary reflector (R2) at its end facing the fluorescent lamp arrangement (LL) merges into an angle foot (R22) which extends into the space under the fluorescent tube arrangement (LL) and whose width (c) the degree of shielding directly below light (LI) radiating onto the lens (SS). 3. workplace lamp according to claim 1 or 2,
characterized,
- That the lens (SS) is divided into a front wide strip area (SB1) and a rear narrow strip area (SB2) in the extent of the housing trough (G),
- That at least the front wide strip area (SB1) is designed as a prism plate with mutually parallel prisms in fine structure on the light incidence side, with prisms running perpendicular to the longitudinal extension of the work table (AT) and
- That the width (f) of the rear narrow strip area (SB2) is chosen so large that the transition between the two strip areas (SB1 / SB2) from the auxiliary reflector (R2) or its angled foot (R22) against that on the lens (SS) direct light) is shielded. 4. workplace lamp according to one of the preceding claims,
characterized,
- That the main reflector (R1), including the auxiliary reflector (R2), is delimited on both sides at right angles by triangular or trapezoidal, flat end reflectors (R3). 5. workplace lamp according to one of the preceding claims,
characterized,
- That the length of the housing trough (G) including the length of the linear fluorescent lamps arranged thereon voltage (LL) and the length (lt) of the work table (AT) are adapted to each other. 6. workplace lamp according to one of the preceding claims,
characterized,
- The prisms of the diffusion plate designed as a prism plate (SS) are a 45 ^o -prism grid (P). 7. workplace lamp according to one of the preceding claims,
characterized,
- That the 45 ^o -prism grid (P) of the diffuser (SS) designed to a prismatic plate has a grid width (RB) of 0.35 mm and a grid depth (RT) of 0.17 mm. 8. workplace lamp according to one of the preceding claims,
characterized,
- That the main reflector (R1) and the two front reflectors (R3) made of anodized aluminum sheet with silk matt mirror surfaces and the auxiliary reflector (R2) made of anodized aluminum sheet with a high-gloss mirror surface. 9. workplace lamp according to one of the preceding claims,
characterized,
- That the projected on the horizontal width (e) of the auxiliary reflector (R2) is chosen so large that the fluorescent lamp arrangement (LL) is not visible at normal eye position (AP) in the direction of view to the rear of the work table (AT). 10. Workplace lamp according to one of the preceding claims,
characterized,
- That the lens (SS) is light-tightly attached to the edges of the housing trough (G). 11. Workplace lamp according to one of the preceding claims,
characterized,
- That the diffuser (SS) designed as a prismatic plate consists of a carrier plate (TP) made of clear glass or clear synthetic glass, for example acrylic glass, which is provided on the side of the light with a clear prismatic film having the desired prismatic structure (PF). 12. Workplace lamp according to one of the preceding claims,
characterized,
- That the rear narrow strip area (SB2) of the lens (SS) is also designed with mutually parallel prisms in fine structure on the light incidence side and
- That here the prisms in the extension of the work table (AT) in width (bt) at an angle δ in the limits 20 ^o ≦ δ ≦ 40 ^o and mirror image to the center line (M) of the narrow strip area divided again in the middle in length (SB2) run. 13. Workplace lamp according to one of claims 1 to 11,
characterized,
- That the rear narrow strip area (SB2) of the support plate (TP) of the lens (SS) on the light incidence side is provided with a light transmittance of 5 to 10% having a lacquer layer or plastic film cover. 14. Workplace lamp according to one of the preceding claims,
characterized,
- That the wide front stripe area (SB1) of the carrier plate (TP) of the lens (SS) in its extension in a prismatic elongated central stripe area (SB11) and two prism-free short edge stripe areas (SB12, SB13) is divided,
- That these edge strip areas (SB12, SB13) are provided on the light incidence side with a light transmittance of 10 to 20% varnish layer or plastic film cover and
- That the width of the edge strip areas (SB12, SB13) have approximately the width of the narrow rear strip area (SB2). 15. Workplace lamp according to one of the preceding claims,
characterized,
- That the carrier plate (TP) of the lens (SS) is provided on its light incidence side including the foil cover or paint coating carrying it with a cover (TAP) in the form of a clear glass plate or clear synthetic glass plate, for example acrylic glass. 16. workstation lamp according to claim 15,
characterized,
- That the clear prism film (PF) having the desired fine prism structure is largely clamped without adhesive between the carrier plate (TP) and the cover (TAP) and for this purpose the carrier plate (TP) and the cover (TAP) are glued together at the edges7 so that the space between them is sealed between the two panels to the outside at the same time. 17. workplace lamp according to one of the preceding claims,
characterized,
- That the carrier plate (TP) of the lens (SS) is provided with a conductive layer which is in a good conductive connection with ground potential.

Images