LAMP STRUCTURE

Abstract: The invention relates to lighting apparatus. The lighting apparatus according to the invention comprises directable optical conductor (10) and a filament or halogen bulb (3) or other light source (3, 4) installed as stationary. The optical conductor (10) is articulated to the lighting apparatus preferably by means of a sleeve bearing (11, 2'), for instance, or by other means so that the position of the optical conductor in relation to the lighting apparatus and the fastening surface (2) of the lighting apparatus can be changed freely. In addition to this, the optical conductor can preferably also be attached in a manner which allows turning it around its central axis. The light beam formed by the lighting apparatus is directed by means of the optical conductor, whereby the mechanical stress caused by directing the beam does not affect the light source. Because the optical conductor and the light source are separate, and the light source (3, 4) is not within the optical conductor, the optical conductor does not warm up considerably, whereby handling it is comfortable for the user.

Description: LAMP STRUCTURE THE OBJECT OF THE INVENTION The invention relates to lighting apparatus, more particularly to directable, small- sized lighting apparatus. DESCRIPTION OF THE TECHNICAL BACKGROUND Figure 1 shows a cross-section of a prior art solution for implementing small, directable light sources. Lighting devices of this kind are very commonly used in coaches and airplanes, for instance. The construction comprises a globular lamp 1, which is attached to a wall 2 with fasteners 2' so that the lamp can be turned. The lamp 1 comprises a bulb 3 and a reflector 4, and the light is conducted out from the lamp through a collar 5 and a front glass 6, which are typical parts of the construction. In a construction like this, the directability of the light beam is limited in extreme positions by the fact that the collar 5 and the fasteners 2' touch each other. In constructions without a protruding collar 5, the fasteners or the wall shade the emitting beam. These factors limit the directability of the construction, which is typically about ±30° to the wall from the perpendicular direction. Heat is also a problem in a structure like this, because the bulb 3 warms the turnable lamp 1. Thereby the collar 5 and the front glass 6 also warm up considerably, which is uncomfortable for the user. Another problem is the fatigue of the conductors 8 caused by moving the lamp. In time, the conductors 8 break easily, especially if tin lamp 1 is turned around its central axis ranning through the bulb 3. Therefore, turning the lamp around its central axis has been prevented in many solutions. SHORT DESCRIPTION OF THE INVENTION It is an object of the invention to provide lighting apparatus, which is simple and can be manufactured at low cost. It is another object of the invention to provide lighting apparatus, which enables directing the light in a versatile fashion and directing the width of the light beam. In addition, the invention aims at providing lighting apparatus according to the aforementioned objects, which is also more durable that the prior art solutions. The objects are achieved by using a rigid optical conductor for directing the light, which optical conductor is articulated to the lighting apparatus by means of a sleeve bearing, for instance. The optical conductor can be, for instance, a transparent plastic rod, the sides of which are coated with a metal layer, but other solutions for the optical conductor are also possible. The light source is attached to the lighting apparatus in a stationary manner. The light beam of the lighting apparatus is directed only by means of the optical conductor, and the light source does not move as a result of the adjustment. A construction like this provides versatile directabiHty of the light beam and a longer service life of the light source compared to the prior art solutions. The system according to the invention is characterized in what is set forth in the characterizing part of the independent claim. Other preferred embodiments of the invention are described in the dependent claims. The lighting apparatus according to the invention comprises a movable optical conductor and a filament or halogen bulb or other light source installed as stationary. The optical conductor is articulated to the lighting apparatus preferably by means of a sleeve bearing, for instance, or by other means so that the position of the optical conductor in relation to the lighting apparatus and the fastening surface of the lighting apparatus can be changed freely. The optical conductor does not touch the light source. In addition to this, the optical conductor can preferably also be attached in a manner which allows nirning it around its central axis. In the solution according to the invention, the light source is an essentially rigid, non- flexible piece. The light beam formed by the lighting apparatus is directed by means of the optical conductor, whereby the mechanical stress caused by directing the beam does not affect the light source. Because the optical conductor and the light source are separate, and the light source is not within the optical conductor, the optical conductor does not warm up considerably, whereby handling it is comfortable for the user. The end of the optical conductor, which is in the vicinity of the light source, is in this application called the inner end for clarity, and correspondingly the end of the conductor, which protrudes from the lighting apparatus and can be touched by the user, is called the outer end. The outer end of the optical conductor can preferably be shaped so as to achieve the desired shape and direction of the light beam. The outer end of the optical conductor can be shaped as a diagonally cut cylinder, for instance, whereby the diagonal cutting directs the beam at the desired angle to the optical conductor. Thus the light beam can be directed in a very versatile fashion by turning the optical conductor around its longitudinal axis and by turning the optical conductor in different positions in relation to the lighting apparatus and the fastening surface of the lighting apparatus. In the construction according to the invention, the light of the light source is directed to the inner end of the optical conductor. The side surfaces of the optical conductor reflect the light directed at the inner end of the optical conductor, whereby light is emitted from the outer end of the optical conductor. The width, intensity distribution and angle to the optical conductor of the light beam eπiitting from the outer end can be varied by the dimensioning of the optical conductor and its distance from the light source. The light source can be implemented so that light is reflected from the side walls of the optical conductor by total reflection. The side walls of the optical conductor can also be coated with a reflective layer. In order to minimize the warming up of the optical conductor, the inner end of the optical conductor can preferably be coated with a layer which reflects infrared radiation but passes visible light, if the optical conductor is made of solid material or if there is a lens at the inner end of the optical conductor. It is also possible to install a light-passing plate, such as a glass or plastic plate on which a layer like i_i has been formed, at the inner end of the optical conductor. A lighting apparatus according to the invention is especially suitable for use in applications in which light should be freely targetable and in which the direction should be steplessly directable in a very wide area, as much as ±90°. The optical conductor is preferably a solid, transparent glass or plastic rod, the side surfaces of which are coated with a reflective layer, e.g. an aluminium layer. Suitable materials include all transparent plastics, such as acrylic plastics, polystyrene plastics, polycarbonate plastics and different types of glass. However, the invention is not limited to this, but the optical conductor can also be a tubular piece with its inner or outer surface coated with a reflective layer. The optical conductor can also be formed by a tubular piece made on non-transparent material, the inner surface of which reflects light. Thus the optical conductor can be made of a metal tube with a polished inner surface, for instance. The ends of the optical conductor can be provided with various lenses, prisms or other kinds of refractive elements to form the desired shape of the lighting spot. If the optical conductor is made of solid material, its end can be shaped as the desired refractive element, and if the optical conductor is made of tubular material, an element like this can be attached to the end of the optical conductor in a known manner, such as gluing. SHORT DESCRIPTION OF THE FIGURES In the following, the invention will be described in more detail with reference to the examples of preferred embodiments and the accompanying drawings, in which Figure 1 shows a prior art lighting apparatus, Figure 2 shows a lighting apparatus according to a preferred embodiment of the invention, Figure 3 shows a lighting apparatus according to a preferred embodiment of the invention, in which the optical conductor can be moved in the direction of its longitudinal axis, Figure 4 shows examples of various shapes of the optical conductor used in different embodiments of the invention, and Figure 5 shows the construction of a preferred embodiment of the invention, The same reference numbers and markings are used for corresponding parts in the figures. A DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Figure 2 shows a preferred embodiment of the invention. The embodiment shown in Figure 2 is suitable for fastening to an essentially horizontal wall 2, such as the surface above the place of a passenger in a coach or airplane. Figure 2 shows a bulb 3 and a reflector 4, which direct the light produced by the bulb at the inner end of the optical conductor 10. The light passes through the optical conductor 10 and comes out from the outer end of the optical conductor. The optical conductor 10 is fastened by means of a sleeve 11 and fasteners 2' to the wall 2 so that the optical conductor can be turned in different angles and rotated around its axis. In Figure 2, the different positions of the optical conductor 10 are illustrated by shapes drawn with dashed lines 10'. The arrows drawn with dotted lines illustrate the different directions of the light beam provided by different positions of the optical conductor 10. Figure 2 also illustrates a preferred embodiment of the invention, in which the end of the optical conductor 10 is cut diagonally for directing the beam in a direction differing from the longitudinal axis of the optical conductor. Figure 3 illustrates a preferred embodiment of the invention, in which the optical conductor 10 is fastened in such a manner that it can be moved in the direction of its longitudinal axis. A construction like this can be implemented e.g. so that the optical conductor 10 can move in relation to a sleeve 11. In the inner position, in which the optical conductor 10 is close to the light source 3, 4, the light beam coming from the outer end of the optical conductor is very wide. In the outer position, in which the inner end of the optical conductor 10 is further from the light source 3, 4, the light beam coming from the outer end of the optical conductor is narrower than in the inner position. If the outer end of the optical conductor is diagonally shaped, as in the example of Figure 2, this positioning in the axial direction also influences, besides the width of the emitting light beam, the angle between the emitting light beam and the longitudinal axis of the optical conduct »ι which angle is the larger the closer the inner end of the optical conductor is to the light source 3, 4. In an embodiment like the example of Figure 3, the movement of the optical conductor is limited to prevent it from touching the light source 3, 4 and from slipping out from the sleeve 11. In the examples of figures 2 and 3 the optical conductor 10 is straight. However, the invention is not limited to this, but the optical conductor can also have another shape, e.g. curved, according to the desired appearance. The cross-section of the optical conductor is preferably circular, but other shapes, such as triangular, are also possible. The shape of the sleeve 11 must correspond to the shape of the optical conductor 10 in each embodiment. In the embodiments in which the cross-section of the optical conductor is not circular, the tumability of the optical conductor around its longitudinal axis is preferably implemented by the tumability of the sleeve 11. The dimensions of the optical conductor 10, such as its thickness and length, can be selected according to the application in question, and the invention is not limited to certain dimensions or relations between dimensions. Figure 4 illustrates some shapes of the optical conductor 10, which are suitable for a lighting apparatus according to the invention. The component figures A, B, C and D show axial sections of four optical conductors 10 with different shapes. The light reflecting areas 12 are drawn with a double line and the light passing areas are drawn with a single line. In an embodiment in which the optical conductor is made of solid, transparent material, the areas 12 in Figure 4 represent areas coated with a reflective layer. The optical conductor with a diagonally cut end shown in the component figure A directs the light beam askew, as shown by the arrows drawn with a dotted line. The optical conductor of the component figure B, in which part of the skew surface reflects light, directs the light beam more strongly askew. In the component figure C, the skew portion reflects light, whereby the optical conductor 10 directs the light in an essentially perpendicular angle to the longitudinal axis. The component figure D illustrates the use of a refractive element 13 at the end of the optical conductor. In this example, the refractive element is a lens at the outer end of the optical conductor, which lens is formed by the shaping of the end of the solid optical conductor. However, the component figure D is only an example of a light refracting element, and the invention is not limited to the example shown. The light refracting element can also be formed at the inner end of the optical conductor, and it can be some other element than a lens. The element 13 can be e.g. a prism or a group of prisms, as was mentioned earlier in this specification. In Figure 4, the perpendicular end of the optical conductors A, B, C and D, the left end in the drawing, is the inner end of the optical conductor, and the right end in the drawing is the outer end of the optical conductor. Figure 5 illustrates a preferred application of the invention, namely a combined general and spot lighting apparatus attached to a wall 23. The construction according to Figure 5 is suitable for use in bedrooms, hotel rooms and ship cabins. The lighting solution shown in Figure 5 comprises a general light 21 and a shade 22, and an directable spot light 3, 4, 10 according to the invention, implemented in the same construction. The general light 21 can be a filament lamp, a fluorescent tube or other known lighting apparatus. The lighting solution according to Figure 5 can be used as general lighting in the room. If a person in the room wants to sleep, the general light 21 can be switched off, whereby the directable spotlamp 3, 4, 10, 11 can be used as reading light without any notable disturbance caused to the person who is sleeping. For the sake of clarity, the constructions related to the electric wires and light switches have been left out from Figure 5. The construction according to the invention enables a very wide area of directability for the light. In addition, in a preferred embodiment of the invention in which the optical conductor is made of plastic, the optical conductor is not essentially heated, whereby it can be comfortably turned with bare hands. In the lighting apparatus according to the invention, the electric wires 8 of the light source 3, 4 are not susceptible to fatigue and are not easily broken, because the light source 3, 4 if installed as stationary. Because of stationary installation, the ventilation possibly needed by the light source 3, 4 is easier to implement than in the prior art solutions according to Figure 1. In the lighting apparatus according to the invention, the moving parts 10, 11 are not as susceptible to the warming effect of the light source 3, 4 as in the known constructions like the one shown in Figure 1. In addition, the lighting apparatus according to the invention has the advantage of simple and low- cost construction. The invention was described above with reference to some of its preferred embodiments, but obviously the invention can be modified in many ways according to the inventive idea defined by the attached claims.

Claims: Claims 1. A lighting apparatus intended for concealed installation in a wall, in which lighting apparatus the light beam can be directed in a desired direction, characterized in that it comprises a light source (3, 4), which is installed as stationary in the lighting apparatus, and which light source is a bulb, and an optical conductor (10), - which is fastened to the lighting apparatus in a turnable manner for directing the light beam formed by the lighting apparatus in the desired direction, and - which optical conductor (10) is an essentially rigid uniform piece, and - which optical conductor (10) can be turned around its longitudinal axis directing the light beam formed by the lighting apparatus, - and which optical conductor has a first end and a second end, whereby said optical conductor is arranged to receive the light produced by the light source through said first end and to direct the light to said second end. 2. A lighting apparatus according to Claim 1, characterized in that the optical conductor (10) can be moved in the direction of its longitudinal axis for adjusting the width of the light beam formed by the lighting apparatus. 3. A lighting apparatus according to Claim 1, characterized in that the optical conductor (10) is a closed piece formed of transparent material, and part of the surface (10) of the optical conductor is coated with a light reflecting layer. 4. A lighting apparatus according to Claim 3, characterized in that the optical conductor is made of glass. 5. A lighting apparatus according to Claim 3, characterized in that the optical conductor is made of plastic. 6. A lighting apparatus according to Claim 1, characterized in that the optical conductor is essentially in the shape of a straight circular cylinder. 7. A lighting apparatus according to Claim 1, characterized in that the outer end of the optical conductor comprises a surface which forms and angle differing essentially from perpendicular in relation to the longitudinal axis of the optical conductor. 8. A lighting apparatus according to Claim 1, characterized in that the optical conductor comprises a light refracting element at least at one end thereof. 9. A lighting apparatus according to Claim 8, characterized in that said light refracting element is a lens. 10. A lighting apparatus according to Claim 8, characterized in that the optical conductor (10) is a closed piece formed of transparent material, and said light refracting element is formed by the shaping of the end of the optical conductor. 11. A lighting apparatus according to Claim 1, characterized in that the optical conductor (10) is a hollow tube. 12. A lighting apparatus according to Claim 11, characterized in that said the inner surface of the optical conductor is coated with a light reflecting layer. 13. A lighting apparatus according to Claim 1, characterized in that the lighting apparatus also comprises a general light (21).

Inventors: RUUTTU JARI, TOERNROOS FILIP, RUUTTU, JARI, TOERNROOS, FILIP
Applicants: RUUTTU JARI, TOERNROOS FILIP, RUUTTU, JARI, TOERNROOS, FILIP
Application year: 1999
Main classification: F21V21
IPC codes: B60Q3, F21S8, F21V8, F21V14, F21V17, F21V21