JP2010027407A - Spotlight - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an irregular color from being generated in a spot light, without making the whole device get voluminous and complicating structure, in a spotlight having discharge lamps different in emission light colors emitted from upper and lower parts. <P>SOLUTION: The spotlight is provided with a metal halide lamp 3, a reflecting mirror 4 for reflecting a light emitted from the lamp 3, and an aperture 5, in a lens barrel 2. The reflecting mirror 4 includes the first, second and third elliptical reflecting mirrors 41, 42, 43. Primary reflection lights L41a, L41b by the first elliptical reflecting mirror 41 advance intactly toward the aperture without being reflected by the third elliptical reflecting mirror 43, primary reflection lights L42a, L42b by the second elliptical reflecting mirror 42 are reflected by the third elliptical reflecting mirror 43, and are vertically inverted to advance toward the aperture 5, the lights L41a, L41b, L43a, L43b arrived at the aperture 5 are thereby mixed each other, and the irregular color is prevented from being generated in the spot light, even when the difference is generated in the colors emitted from upper and lower portions of the lamp 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spotlight having a discharge lamp as a light source.

  In a discharge lamp, the gaseous metal sealed in the arc tube tends to be unevenly distributed downward due to the influence of gravity with the passage of time, and when the degree of uneven distribution increases, the discharge lamp is emitted above and below the lamp. There are also differences in the color of light. The above-mentioned problem is conspicuous in a spotlight in which a metal halide lamp is provided such that the longitudinal direction thereof is in the horizontal direction, and light emitted from the lamp is condensed forward in the horizontal direction by a lens.

  A conventional spotlight provided with a metal halide lamp as a light source will be described with reference to FIG. The spotlight 100 has a metal halide lamp 102 (hereinafter referred to as a lamp) as a light source, a reflecting mirror 103 that reflects light emitted from the lamp 102 and sends it forward, and an opening having a predetermined diameter. The aperture 104 which has and the condensing lens part 105 are provided.

  The reflecting mirror 103 has an elliptical shape formed by rotating an elliptical arc around the central axis 106 in the longitudinal direction of the lamp 102, and one focal point 103a is located at the light emitting portion of the lamp 102, and the other focal point 103b is It is provided so as to be positioned between the aperture 104 and the condenser lens unit 105. In the spotlight 100, the light 107 a emitted from the lower part of the lamp 102 is yellowish compared to the light 107 b emitted from the upper part, and passes through substantially the lower half of the opening of the aperture 104. On the other hand, the light 107b emitted from the upper part of the lamp 102 passes through substantially the upper half of the opening of the aperture 104, and both the light 107a and 107b are irradiated as they are without being mixed to form the spot light 108. Accordingly, the spot light 108 is more yellowish toward the top.

  In order to eliminate the disadvantages of the spotlight 100, there is a spotlight in which the shape of the reflecting mirror 103 is changed so that light emitted from the lamp 102 is mixed at the position of the aperture 104. As shown in FIG. 5, the spotlight 200 includes a reflecting mirror 203, a first elliptical portion 203a formed by rotating an elliptical arc around the central axis 106 in the longitudinal direction of the lamp 102, and the first elliptical portion 203a. The second elliptical portion 203b is formed by rotating an elliptical arc starting from the edge of the first elliptical portion 203a. The structure of the part other than the reflecting mirror 203 is the same as that of the spotlight 100.

  One focal point 203fa of the first elliptical portion 203a and one focal point 203fb of the second elliptical portion 203b are both positioned at the light emitting portion of the lamp 102, and the other focal point of the first elliptical portion 203a. 203fa is positioned closer to the lamp 102 than the aperture 104, and the other focal point 203fb of the second elliptical portion 203b is positioned closer to the lens unit 105 than the aperture 104.

  In the spotlight 200, the light reflected by the first elliptical portion 203a out of the light 207a emitted from the lower part of the lamp 102 passes mainly through the upper half of the opening of the aperture 104, and the second ellipse. The light reflected by the shape part 203 b passes mainly through the lower half of the opening of the aperture 104. Of the light 207b emitted from the upper part of the lamp 102, the light reflected by the first elliptical portion 203a passes mainly through the lower half of the opening of the aperture 104 and is reflected by the second elliptical portion 203b. The reflected light passes mainly through the upper half of the aperture 104 aperture.

  As described above, the light 207b and 207a emitted from the upper part and the lower part of the lamp 102 are mixed at the position of the aperture 104, and the light traveling from the aperture 104 as the pseudo light source toward the lens unit 105 has no color unevenness. Become light. However, the light reflected by the first elliptical portion 203a out of the light toward the lens unit 105 spreads at a large angle after passing through the aperture 104, so that the peripheral part is the holder 105a of the lens unit 105 or the lens barrel 101. There is a possibility that the unevenness of the color of the spot light 108 will not be eliminated without being contributed to the formation of the spot light 108.

  Further, in order to eliminate the problem that the peripheral edge of the light reflected by the first elliptical portion 203a is cut, a spot in which the diameter of the front portion 101b of the lens barrel 101 is increased as shown in FIG. The light 300 may be considered. In this case, however, the spotlight 300 as a whole has the disadvantage that the bulk of the spotlight 300 becomes large. In addition, the light passing through the periphery of the lens unit 105 is affected by the aberration of the lens. 108 has the disadvantage that the contour is blurred. In order to eliminate the influence due to the aberration of the lens, an aspheric lens may be used or the number of lenses may be increased. However, this increases the cost of the lens unit 105 and increases the cost.

On the other hand, in order to improve the utilization efficiency of light emitted from a lamp, a spotlight in which a part of an elliptical reflecting mirror is formed on a paraboloid is known (for example, see Patent Document 1). In this spotlight, a portion of the elliptical reflector close to the central axis in the longitudinal direction of the lamp is formed on the paraboloid, and the light emitted from the lamp and reflected by the paraboloid of the reflector is the center. The light quantity in the vicinity of the central axis is prevented from decreasing in parallel to the axis toward the aperture opening.
JP 2004-31056 A

  As described above, in spotlights using discharge lamps with different light colors emitted from the top and bottom as light sources, uneven color of spotlights is eliminated without increasing the overall volume of the device or complicating the structure. That was not easy.

  Therefore, the present invention solves the above-described problems, and does not increase the overall volume of the apparatus or complicate the structure, does not cause uneven color in the spot light formed on the irradiation surface, and blurs the outline. The object is to provide a spotlight that never happens.

  In order to achieve the above object, the invention of claim 1 is directed to a discharge lamp, a first elliptical reflecting mirror formed by rotating an elliptical arc around a central axis in a longitudinal direction of the discharge lamp, A second elliptical reflector formed by rotating an elliptical arc starting from the edge of the first elliptical reflecting mirror; and an elliptical arc starting from the edge of the second elliptical reflecting mirror. A spotlight including a third elliptical reflecting mirror and an aperture provided facing an opening edge of the third elliptical reflecting mirror, wherein the third elliptical reflecting mirror includes: Either the primary reflected light by the first elliptical reflecting mirror or the primary reflected light by the second elliptical reflecting mirror is reflected as secondary reflected light, and the second reflected light by the third elliptical reflecting mirror is reflected. Next reflected light and the first ellipse not reflected by the third elliptic reflector Primary reflected light from the reflecting mirror, or primary reflected light by the second elliptical reflector, characterized in that toward the central axis as it passes through the aperture.

  According to a second aspect of the present invention, in the spotlight of the first aspect, one of the two focal points of the second elliptical reflecting mirror is positioned at a light emitting portion of the discharge lamp, and the other is the second elliptical reflecting. It is located at the intersection of the boundary surface of the mirror and the third elliptical reflecting mirror and the central axis.

  According to the invention of claim 1, either the primary reflected light by the first elliptical reflecting mirror or the primary reflected light by the second elliptical reflecting mirror is reflected by the third elliptical reflecting mirror, Since the other is not reflected and goes to the aperture as it is, the light that is reflected by the third elliptical reflecting mirror and reaches the aperture and the light that reaches the aperture without being reflected are upside down in the plane of the aperture. The light passing through and emitted from the upper and lower portions of the discharge lamp mixes at the aperture position, and the spot light does not have color unevenness. In addition, since the light emitted from the discharge lamp and directed to the aperture becomes light directed to the central axis when passing through the aperture, the light is condensed near the center of the lens portion, and the lens diameter is enlarged, Even with a compact and simple configuration that does not take measures such as adopting an aspheric lens to improve aberrations, spot color does not cause color unevenness and the contour does not blur.

  According to the invention of claim 2, one of the two focal points of the second elliptical reflecting mirror is located at the light emitting portion of the discharge lamp, and the other is the second elliptical reflecting mirror and the third elliptical reflecting mirror. Therefore, the inner diameter of the boundary surface can be made smaller than the maximum value of the inner diameter of the second elliptical reflecting mirror, and the reflecting mirror can be configured compactly. The entire apparatus can be configured compactly.

  Hereinafter, a spotlight according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 shows the entire spotlight of the present embodiment, and FIG. 2 shows an enlarged view of the reflector portion. The spotlight 1 of the present embodiment has a metal halide lamp 3 (hereinafter referred to as a lamp) as a light source and a light emitted from the lamp 3 directed forward (to the right in FIGS. 1 and 2) in a lens barrel 2. The reflecting mirror 4 which reflects, the aperture 5 provided in front of the reflecting mirror 4, and the lens part 6 provided in the opening end of the lens barrel 2 are provided. The lamp 3 is mounted such that the central axis 7 in the longitudinal direction is horizontal, and is turned on when power is supplied from a ballast 8 outside the lens barrel 2. The lamp 3 is a lamp in which a metal halide such as sodium or scandium and mercury are enclosed as a mixed vapor in an arc tube and emits light by arc discharge.

  The aperture 5 is provided at the focal position of the lens unit 6, and has an opening 5 a having a predetermined diameter for restricting the light emitted from the lamp 3. The shape of the spot light 9 formed on the irradiated surface is the same as that of the opening 5a. Although it is circular in this embodiment, it can be in any shape.

  The reflecting mirror 4 is formed, for example, by drawing an aluminum plate into a predetermined shape, or by forming a light reflecting film such as an aluminum film on a press-molded glass substrate. In addition, the reflecting mirror 4 may be an integrated body molded from the same material, or may be obtained by joining split molds that are produced by dividing into a plurality of parts.

  As shown in FIGS. 2 and 3, the shape of the reflecting mirror 4 is a combination of three oval portions 41, 42, and 43 having different focal points. Hereinafter, the three parts will be described in the order of the first elliptical reflecting mirror 41, the second elliptical reflecting mirror 42, and the third elliptical reflecting mirror 43 in order from the part closer to the lamp 3.

  The first elliptical reflecting mirror 41 is formed by rotating an elliptical arc with the central axis 7 in the longitudinal direction of the lamp 3 as the rotation axis, and the second elliptical reflecting mirror 42 is the first elliptical reflecting mirror 41. The third elliptical reflecting mirror 43 is formed by rotating an elliptical arc starting from the edge 41p of the second elliptical mirror with the central axis 7 as the rotation axis. The arc is rotated about the central axis 7 as a rotation axis.

  In the first elliptical reflecting mirror 41, one focal point 41 a is positioned at the light emitting portion of the lamp 3, and the other focal point 41 b is positioned closer to the lens unit 6 than the aperture 5. In the second elliptical reflecting mirror 42, one focal point 42 a is positioned at the light emitting portion of the lamp 3, and the other focal point 42 b is a boundary surface between the second elliptical reflecting mirror 42 and the third elliptical reflecting mirror 43. It is located at the intersection P between 50 and the central axis 7. In the third elliptical reflecting mirror 43, one focal point 43 a is positioned at the intersection P, and the other focal point 43 b is positioned closer to the lens unit 6 than the aperture 5.

  Since the other focal point 42b of the second elliptical reflecting mirror 42 is positioned at the intersection P between the boundary surface 50 and the central axis 7, the inner diameter of the boundary surface 50 is set to the inner diameter of the second elliptical reflecting mirror 42. And the bulk of the reflecting mirror 4 as a whole can be reduced. In other words, since the shape of the second ellipsoidal reflecting mirror 42 does not become a trumpet shape that opens forward, the inner diameter of the reflecting mirror at the boundary surface 50 can be reduced, and the third ellipsoidal reflecting amount correspondingly. The diameter of the mirror 43 can be reduced.

  Since the shape of each of the elliptical reflecting mirrors 41, 42, 43 is as described above, the primary reflected light L 42 a, L 42 b from the second elliptical reflecting mirror 42 is secondary by the third elliptical reflecting mirror 43. Reflected as reflected light L43a and L43b, the primary reflected light L41a and L41b from the first elliptical reflecting mirror 41 becomes light that converges at a gentle angle close to the horizontal, and travels toward the aperture 5 to form the third elliptical reflecting mirror. 43 is not reflected.

  Next, an optical path until the light emitted from the lamp 3 forms the spot light 9 will be described with reference to FIG. The primary reflected light L41a emitted from the lower part of the lamp 3 and reflected by the first elliptical reflecting mirror 41 becomes light directed toward the central axis 7 at a gentle angle close to the horizontal and substantially below the opening 5a of the aperture 5. The primary reflected light L41b that has passed through the half and emitted from the upper part of the lamp 3 and reflected by the first elliptical reflecting mirror 41 becomes light directed toward the central axis 7 at a gentle angle close to the horizontal, and the light of the aperture 5 It passes through substantially the upper half of the opening 5a. The primary reflected lights L41a and L41b that have passed through the aperture 5 are condensed by the lens unit 6 to form spot light 9.

  On the other hand, the light L42a emitted from the lower part of the lamp 3 and reflected by the second elliptical reflecting mirror 42 is subsequently reflected by the third elliptical reflecting mirror 43 to become the secondary reflected light L43a. It passes through substantially the upper half of the opening 5a of the aperture 5 at a steep angle. The light L42b emitted from the upper part of the lamp 3 and reflected by the second elliptical reflecting mirror 42 is subsequently reflected by the third elliptical reflecting mirror 43 to become the secondary reflected light L43b, which is also relatively steep. It passes through the substantially lower half of the opening 5a of the aperture 5 at a certain angle. The secondary reflected lights L43a and L43b that have passed through the aperture 5 are condensed by the lens unit 6 to form spot light 9.

  As described above, the primary reflected light L41a and L41b reflected by the first elliptical reflecting mirror 41 toward the central axis 7 at a gentle angle and the second and third elliptical reflecting mirrors 42 and 43 are sequentially reflected. The secondary reflected light L43a and L43b thus produced have opposite upper and lower phases at the position of the aperture 5, so that even when the light beams are mixed and the color of the emitted light is different above and below the lamp 3, the aperture Color unevenness does not occur at the 5 position.

  Further, the primary reflected lights L41a and L41b that pass through the aperture 5 and travel toward the lens unit 6 travel toward the central axis 7 at a gentle angle close to the horizontal, and thus are condensed near the center of the lens unit 6 and the peripheral edge is cut. And is not affected by lens aberration. Similarly, the secondary reflected lights L43a and L43b that pass through the aperture 5 and travel toward the lens unit 6 also travel toward the central axis 7, so that the diameter of the light beam does not suddenly increase and is collected near the center of the lens unit 6. Lighted. Thus, since the primary reflected light L41a, L41b and the secondary reflected light L43a, L43b are both condensed near the center of the lens unit 6, in order to enlarge the diameter of the lens unit 6 and remove the influence of aberrations. It is not necessary to make the lens of the lens unit 6 special.

  As described above, the primary reflected light L41a, L41b and the secondary reflected light L43a, L43b are mixed with each other at the position of the aperture 5, so both reflected lights L41a, L41b, L43a, L43b that have passed through the lens unit 6 are mixed. The spot light 9 formed by the above has no color unevenness. Further, both reflected lights L41a, L41b, L43a, and L43b have a small diameter even in the vicinity of the lens portion 6, and the peripheral portion is not cut or affected by aberration due to the peripheral portion of the lens. No. 9 has a clear outline and no color unevenness.

  The focal point 41b position of the first elliptical reflecting mirror 41 and the focal point 43b position of the third elliptical reflecting mirror 43 will be further described. When the focal point 41b of the first elliptical reflecting mirror 41 and the focal point 43b of the third elliptical reflecting mirror 43 are both too close to the aperture 5 when setting their positions, the light as a pseudo light source at the opening 5a of the aperture 5 There is a situation in which the uniformity is reduced, and if it is too far, the ratio of being cut by the aperture 5 increases. Therefore, both the focal points 41b and 43b are set at positions where the uniformity of light at the position of the aperture 5 becomes good and the cut ratio is minimized.

  Specifically, as shown in FIG. 2, the position of the focal point 41 b of the first elliptical reflecting mirror 41 is the outermost side reflected by the edge 41 p corresponding to the outermost periphery of the first elliptical reflecting mirror 41. The primary reflected light L41b ′ is set so as to pass through the edge of the opening 5a of the aperture 5. As a result, the diameter of the light beams of the primary reflected light L41a and L41b at the position of the aperture 5 is substantially the same as the diameter of the opening 5a, the light uniformity is improved, and the ratio of being cut by the aperture 5 is minimized. be able to.

  Similarly, the position of the focal point 43b of the third elliptical reflecting mirror 43 is such that the outermost secondary reflected light L43a ′ reflected by the opening edge 43p corresponding to the outermost periphery of the third elliptical reflecting mirror 43 is the aperture 5. It is set to pass through the edge of the opening 5a. Thereby, the uniformity of the light in the opening part 5a of the light flux of the secondary reflected light L43a and L43b is improved, and the ratio cut by the aperture 5 can be minimized.

  As described above, in the spotlight 1 of the present embodiment, the primary reflected light L42a and L42b from the second elliptical reflecting mirror 42 is reflected by the third elliptical reflecting mirror 43, and the first elliptical reflecting mirror 41 is obtained. Since the primary reflected lights L41a and L41b are not reflected and go to the aperture 5 as they are, both the lights L42a, L42b, L41a and L41b pass upside down in the plane of the aperture 5, and the spot light 9 has uneven color. Absent. Further, the light emitted from the discharge lamp 3 and traveling toward the aperture 5 travels toward the central axis 7 when passing through the aperture 5, and thus is collected near the center of the lens unit 6. Accordingly, even if the compact and simple configuration does not take measures such as increasing the diameter of the lens portion 6 or adopting an aspherical lens to improve the aberration of the lens, the spot light 9 does not have color unevenness. , The contour will not blur.

The longitudinal cross-sectional view of the spotlight which concerns on one Embodiment of this invention. The longitudinal cross-sectional view which shows the optical path of the light emitted from the principal part and the discharge lamp of the spotlight. The perspective view of the reflective mirror of the spotlight. The longitudinal cross-sectional view which shows an example of the conventional spotlight. The longitudinal cross-sectional view which shows the other example of the conventional spotlight. The longitudinal cross-sectional view which shows the other example of the conventional spotlight.

Explanation of symbols

1 Spotlight 3 Metal halide lamp (discharge lamp)
5 Aperture 7 Center axis 41 First elliptical reflecting mirror 41p Edge of first elliptical reflecting mirror 42 Second elliptical reflecting mirror 42a One focal point 42b of second elliptical reflecting mirror Second elliptical reflecting The other focal point 42p of the mirror The edge 43 of the second elliptical reflecting mirror 43 The third elliptical reflecting mirror 43p The opening edge 50 of the third elliptical reflecting mirror Boundary surfaces L41a, L41b Primary reflected light L43a, L43b Secondary reflected light P intersection

Claims (2)

A discharge lamp;
A first elliptical reflecting mirror formed by rotating an elliptical arc around the central axis in the longitudinal direction of the discharge lamp;
A second elliptical reflecting mirror formed by rotating an elliptical arc starting from an edge of the first elliptical reflecting mirror;
A third elliptical reflector formed by rotating an elliptical arc starting from the edge of the second elliptical reflector;
An aperture provided facing an opening edge of the third elliptical reflecting mirror, and a spotlight comprising:
The third elliptical reflector is
The primary reflected light by the first elliptical reflecting mirror or the primary reflected light by the second elliptical reflecting mirror is reflected as secondary reflected light,
Secondary reflected light by the third elliptical reflecting mirror and primary reflected light by the first elliptical reflecting mirror not reflected by the third elliptical reflecting mirror, or primary by the second elliptical reflecting mirror The reflected light travels toward the central axis when passing through the aperture.   One of the two focal points of the second elliptical reflecting mirror is positioned at the light emitting portion of the discharge lamp, and the other is the boundary surface between the second elliptical reflecting mirror and the third elliptical reflecting mirror, and the The spotlight according to claim 1, wherein the spotlight is located at an intersection with the central axis.