JP2003262915A - Fixed star projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed star projector which can downsize a fixed star globe, can decrease the ineffective luminous fluxes leaking outside projection units, can improve the utilization efficiency of luminous fluxes, and can arbitrarily turn stars to be projected on and off over the entire surface or in a specific range and can change their brightness without changing the light quantity of a light source lamp. <P>SOLUTION: The light source lamp 5 with a mirror is lighted by a power source device 11 for a light source. The exit light thereof is reflected perpendicularly by the mirror 6 and is made incident through a focal position 13 on the interior of the fixed start globe 7. Part of the rays is refracted by a concave lens 9 having negative reflecting power and illuminates the projection units 2a, 2b, 2e, and 2f existing on the side opposite to the incident direction of the rays. The other rays are reflected by a convex mirror 10 having a hole at its center and illuminates the projection units 2c and 2d existing on the incident direction side of the rays. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a star projector used for planetarium and the like.

[0002]

2. Description of the Related Art When projecting a star on a hemispherical dome screen with a planetarium, a conventional star projection device 42 as shown in FIG. 5 is known. A light source lamp 43 is arranged at the center of a hemispherical star projection sphere, and projection units 41a to 41e are attached around the light source lamp 43 so as to surround the light source lamp 43.

The projection unit is constructed as shown in FIG. The light emitted from the light source is the condenser lens 51.
Then, a projection original plate 50 having fine transmission holes corresponding to an actual star is passed through a light-shielding film, and a projection lens 52 projects a star field in a predetermined range. Divide the whole sky into multiple projection planes, for example 32
A projection unit including projection original plates corresponding to six surfaces or more is mounted at a mounting angle corresponding to the projection surface. According to such a star projection sphere, the star field projected from the plurality of projection units 41 can be reproduced as if the starry sky was uniformly connected.

By constructing a star projection sphere as shown in FIG. 7 and inclining the daily rotation axis 44 at an angle equal to the latitude of the observing site, the starry sky of the observing site can be reproduced. Further, when the star projection sphere is rotated around the diurnal rotation axis 44, the diurnal motion of the starry sky and changes in longitude can be reproduced.

FIG. 8 shows an example of a conventional technique in which two star projection spheres are combined so as to face each other. By combining the star projection spheres 47 and 48 that include projection original plates corresponding to the southern and northern heavenly fields, respectively, it is possible to reproduce the entire heavenly starfield that combines the southern and northern heavens. Furthermore, rotating the diurnal rotation axis 44 as the center will reproduce the diurnal motion of the starry sky and changes in longitude, and rotating the diurnal rotation axis 45 as the center will reproduce changes in the latitude of the set observation site. You can 64
Is a light-shielding hemisphere for shading below the horizon, which serves to prevent stars from being reflected on floors below the horizontal plane.

FIG. 9 is a view showing an example of a publicly known horizon-bottom shading device attached to each projection unit. A light-shielding hemisphere 64 mounted so as to cover the projection lens 52 is held by a bearing 65 so as to be freely rotatable about an optical axis 66 and a bearing 68 about an axis 67. A weight 69 is attached to a part of the light-shielding hemisphere 64. By this function, the light-shielding hemisphere always keeps the horizontal position, and blocks the light rays emitted from the projection lens 52 that are directed downward from the horizontal. This can prevent stars from being reflected on the floor or walls.

FIG. 10 is a diagram showing another example of a known shading device that obtains the same effect as that of FIG. 9 by surrounding the entire star projector with a cover. A large number of light-shielding plates 60 are stacked and attached so that only light directed upward from the horizontal can pass through. This can prevent the stars from being reflected on the floor or walls.

FIG. 11 is a diagram showing an example of a conventional technique for improving the brightness of a star image projected by the projection unit. The light rays emitted from the light source are received by the condenser lens 53,
The light is focused on the end face of the optical fiber bundle 54 composed of a plurality of optical fibers. The position of the opposite end face of each optical fiber,
The brightness of the projected image is improved by matching the transmission holes of the original projection plate with each other and guiding the light rays to the transmission holes more efficiently than in the prior art of FIG.

[0009]

In these star projection devices according to the prior art, it is necessary to use a powerful light source in order to make the projected star image as bright as possible. For example, a light source such as a halogen lamp generates a strong heat. Accordingly, it is necessary to sufficiently cool the light source. However, the inside of the stellar sphere is a space with a limited volume, and in order to prevent leakage from the light source, it is impossible to unnecessarily provide a large cooling port, and it is difficult to suppress heat generation inside the stellar sphere. It was Moreover, because of this, a large wattage light source could not be used, and the brightness of the star image could not be sufficiently increased. Further, in order to prevent the light source and the projection unit from being damaged by the temperature rise due to heat generation, it is necessary to make the star projection sphere large to some extent, which hinders the miniaturization of the star projection sphere.

In the prior art, a large proportion of the light emitted from the light source is the light flux that is not made incident on the projection unit, resulting in a decrease in projector efficiency and a decrease in light quantity. It was necessary, and for this reason also hindered the downsizing of the projector. Moreover,
Since light source lamps such as halogen lamps have a limited lifespan, it must be constructed so that they can be replaced periodically.In the conventional technology, the light source lamp is placed in the center of the stellar sphere, so it is easy and safe to replace it. There was a design constraint in making such a structure possible, and there were constraints in downsizing and cost reduction of the projection apparatus.

When the brightness of a star is improved by the conventional technique shown in FIG. 11, it is necessary to connect the transmission holes randomly arranged on the projection original plate with the optical fibers of which the number is equal to the number of the stars. There has been a problem that the cost is high and the cost of the entire product is increased. Further, as shown in FIG. 8, when the light source is assembled so as to project all-sky stars, the light source is housed inside the rotating body, so parts such as a slip ring are required to send power to the light source. However, not only the cost is increased, but also the contact of the slip ring becomes a worn part, which causes a problem that maintenance is required.

Next, in the prior art as shown in FIGS. 7 and 8,
From zero to 100 by changing the power supply voltage as a light source
%, Halogen lamps that can control light in an arbitrary range have been widely used, but halogen lamps are inferior in terms of efficiency and color temperature compared to discharge lamps such as metal halide lamps, and produce a real bright star image. I couldn't reproduce it. In planetarium stellar projection devices, it is necessary to be able to smoothly change the brightness of the star from zero to 100% according to various effects, but in principle, discharge lamps such as metal halide lamps have a light intensity of zero to 100%. It is difficult to change smoothly up to%. When used as a light source for a planetarium, it is necessary to equip each projection lens with a mechanism such as a shutter and a diaphragm for dimming, which causes a cost increase of the projection apparatus.

Further, in the prior art as shown in FIG. 8, it is necessary to attach a special shutter device as shown in FIG. 9 to each lens in order to prevent stars from being reflected on the floor or walls.
However, there have been problems such as an increase in the cost of the device, malfunction, and maintainability. Further, in the device as shown in FIG. 10, since the cover surrounds the entire projector, the entire device is bulky, and there is an obstacle in transportability, and the design is restricted. It is an object of the present invention to provide a star projector capable of solving the above problems of the prior art.

[0014]

In order to achieve the above object, a star projector according to the present invention is a star projector for a starry sky in a planetarium for projecting a starry sky by a star projection sphere including a plurality of projection units. A light ray emitted from a light source placed outside the projection sphere is guided to the inside of the star projection sphere through a hollow rotation axis, and a lens having a negative refractive power or a reflector having a convex surface is arranged near the center of the star projection sphere. Divergent light is made by refracting or reflecting light rays by the optical unit, and each ray direction of the divergent light is made to coincide with the optical axis of the plurality of projection units so as to illuminate the star plane projection surface uniformly. There is. The present invention is the above star projector, wherein the surface of a lens having a negative refractive power or a reflecting mirror having a convex surface arranged near the center of the star projection sphere is constituted by a plurality of flat surfaces or curved surfaces, and divergence occurs at these surfaces. By arranging the lens or reflecting mirror and the projection units so that the respective light beams of the divergent light can be guided only in the direction in which the projection units exist, the light beams are efficiently guided to the projection units. Has been done. The present invention, in the above-mentioned stellar projector, directs an emitted light beam from a light source through a rotation axis that is orthogonal to the rotation axis of the stellar projection sphere and has a function of tilting the stellar projection sphere, and uses a mirror or prism to It is configured to guide light to the center of the rotation axis and efficiently guide light to each projection unit. The present invention is configured such that, in the above star projector, two sets of the star projectors are opposed to each other and are combined to eliminate the projection dead angle due to the rotation axis and to project the whole sky. The present invention, in the above star projector,
A dimming element capable of varying the optical density is arranged in the optical path from the light source to change the projected luminous intensity of a star. The light control element in the present invention is an element that can change the density or the transmittance in any pattern, or can change the reflectance or the reflection angle in any pattern, and changes the projected luminous intensity of a star in any pattern. It is configured to be possible. The light control element in the present invention is composed of a liquid crystal element, a movable shutter or a DMD (digital micro device) element.

That is, the light source lamp is installed outside the star projection sphere, and the emitted light from this is guided inside the star sphere using optical parts such as mirrors and prisms. By refracting and reflecting using an optical element composed of a convex mirror, a light beam is guided to each projection unit as if the light source is installed at the center of the star projection sphere. Also,
By constructing the concave lens and the convex mirror with not only a uniform curved surface but also a plurality of flat surfaces or curved surfaces, it is possible to reduce the invalid light flux leaking out of the projection unit and improve the light flux utilization efficiency. Characterize. further,
An element or shutter that can change the transmittance is inserted in the exit light path of the light source lamp to turn on / off the projected stars on the entire surface or in a specific range and change the brightness arbitrarily without changing the light intensity of the light source lamp. It is characterized by having done.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a first embodiment of a star projector according to the present invention. The light source lamp 5 with a mirror is turned on by the power source device 11 for the light source. The emitted light is reflected at a right angle by the mirror 6, passes through the focal point position 13 and enters the star projection sphere 7. A part of this ray is refracted by the concave lens 9 having a negative refracting power, and the projection unit 2 located on the side opposite to the ray incident direction.
Illuminate a, 2b, 2e and 2f. On the other hand, the other light rays are reflected by the convex mirror 10 having a hole in the center and illuminate the projection units 2c and 2d located on the light ray incident direction side.

Reference numeral 8 denotes a shutter capable of controlling transmission / non-transmission of light rays or a light control element (hereinafter referred to as “light control element etc.”) capable of uniformly changing the light transmittance. Controlled. By inserting this into the incident optical path, the star projection image can be turned on / off and the brightness can be changed without changing the light source lamp 5 with a mirror.

Further, it is possible to use a light control element capable of producing an arbitrary light-shielding pattern, for example, a matrix type liquid crystal element capable of producing an arbitrary light-shielding pattern such as used in a transmissive display. It is possible to block only the stars in an arbitrary range by installing this matrix type liquid crystal element at a position on the optical axis that is appropriately separated from the focal point position 13 and controlling the light blocking pattern of the liquid crystal element appropriately. . By using this liquid crystal element, for example, you can hide the stars in the area that you do not want to project by hiding under the horizon, or when superimposing some image on the starry sky, project only the part of the star that overlaps the image. It can be erased. In addition, a movable shutter or DMD element can be used as the light control element.

Although the embodiment of FIG. 1 shows an example in which a concave lens and a convex mirror are combined as an optical system for divergence arranged at the center of the star sphere 7, it may be constituted by only a concave lens or only a convex mirror. . When only the concave lens is used, the refractive index of the concave lens may be expanded so that the refracted light reaches the position where the light is reflected by the convex mirror in FIG. On the other hand, in the case of only the convex mirror, the reflecting surface of the convex mirror may be wide-angled and the installation angle may be adjusted so that the reflected light reaches the position where the light is refracted by the concave lens in FIG.

In the present invention, since the light source lamp is located at a substantially fixed position, a slip ring or the like is not required for connection with the power supply device 11, and a structure in which the light source lamp is directly connected by an electric wire can be adopted. Further, since the light source lamp is arranged outside the stellar sphere, the amount of heat generated inside the stellar sphere is much smaller than that of the conventional example, and the size of the stellar sphere can be reduced. Furthermore, it is not necessary to provide a large cooling port for cooling the inside of the star sphere,
Shading is also simple. Further, since the light source lamp is arranged at a substantially fixed position, not only the light source lamp can be cooled easily, but also maintenance workability such as replacement is improved.

FIG. 2 is a schematic diagram showing a second embodiment of the star projector according to the present invention. This embodiment incorporates two northern star spheres and a southern star sphere. Light emitted from the mirror-equipped light source lamp 15a turned on by the power supply device 21a is controlled by the control device 22a.
After passing through, the exit angle is adjusted by the concave lens 31a, and the light is reflected by the mirror 32a at a substantially right angle. Further prism 33a
After the angle is corrected by, the lens 19a having a negative refractive power
The divergence, that is, the exit angle is expanded by the
Projection units 23a, 23b, 23c and 23 in a
Illuminate d. On the other hand, the light emitted from the mirror-equipped light source lamp 15b, which is located at a position relative to 15a, is similarly emitted from the south star sphere 3
Projection units 24a, 24b, 24c and 2 in 4b
Illuminate 4d. As a result, stars can be projected on the whole sky with almost no blind spots.

By rotating both the northern and southern star spheres around the diurnal axis 4, the diurnal motion of the starry sky can be reproduced, and by rotating around the latitudinal axis 3, the change in latitude can be reproduced. . If the light control elements 18a and 18b can form an arbitrary light-shielding pattern, for example, if a transmissive liquid crystal panel is used,
Of course, it is possible to block the stars below the horizon and to erase only the stars in a specific range, as in the above embodiment.

FIG. 3 shows that in the first and second embodiments, the surfaces of the lenses 9 and 19a and 19b having negative refracting power are not a uniform curved surface but a plurality of curved surfaces 39a to 39a.
It is an external view of the concave lens system comprised by 39j. The surface is cut so that the refractive index increases outward from the optical axis of the concave lens system. Each cut surface may be a flat surface instead of a curved surface.

FIG. 4 is a partial sectional view of a star sphere using the concave lens of FIG. An incident light flux 35 from the light source side is incident on the multifaceted lens 36, and exit surface 37a, 37b and 3 are formed.
After 7c, the light enters the projection units 38a, 38b and 38c, respectively. At this time, the projection units 38a, 38
b and 38c and the emitting surface 37a, 37b and 37
By properly maintaining the positional relationship of c, the emission component surface 37
Light that has passed through a, 37b and 37c is incident on the projection unit at a higher rate than if a single curved lens were used. With such a configuration, the loss of luminous flux, which has been a problem in the past, can be significantly reduced, the brightness can be improved, and the required lamp power can be reduced. In FIGS. 3 and 4, an example in which a polyhedral lens is used as a lens having a negative refractive power as a divergence optical system has been described.
Of course, the same effect as that obtained by forming the surface of the convex mirror by a plurality of surfaces can be obtained.

[0025]

As described above, according to the present invention,
Since the light source may be arranged inside the star sphere as in the prior art, the star sphere can be made much smaller than the conventional example. Further, since the light source lamp is arranged outside the star sphere, not only the light source lamp can be easily cooled, but also replacement and maintenance of the lamp are facilitated.
Furthermore, in the conventional example, since the light source needed a wide light distribution characteristic, the type of light source that could be used was extremely limited.
According to the present invention, since it is possible to easily perform dimming without changing the light amount of the light source lamp, it is difficult to dimming, so that it is easy to adopt a discharge lamp whose application to the planetarium is limited. Is possible. Furthermore, since a light source that emits emitted light can be used for one side, for example, metal halide lamps for projectors, high-pressure mercury lamps, etc., which have become popular for liquid crystal projectors in recent years, and whose cost and performance are significantly improved with the expansion of the market. It will be possible to use it, and open the way to increase the degree of freedom in design, reduce the cost of light source lamps, improve procurement, and improve brightness.

Further, according to the present invention, the stars under the horizon can be shielded from light without using a complicated mechanical shutter mechanism or a cover having a large size unlike the conventional one, so that the cover can be manufactured at a lower cost than the mechanical shutter. The device can be made more compact than the method used.

[Brief description of drawings]

FIG. 1 is a schematic view showing a first embodiment of a star projector according to the present invention.

FIG. 2 is a schematic diagram showing a second embodiment of a star projector according to the present invention.

FIG. 3 is a perspective view showing an example of a surface shape of a lens having a negative refractive index.

FIG. 4 is a partial schematic view showing a state where the lens of FIG. 3 is applied.

FIG. 5 is a partial schematic diagram for explaining an example of a conventional star projection device.

FIG. 6 is a cross-sectional view for explaining the structure of the projection unit.

FIG. 7 is a schematic view showing an example of assembly of the star projection device of FIG.

FIG. 8 is a partial schematic view for explaining another example of a conventional star projection device, which is a combination of two star projection spheres facing each other.

FIG. 9 is a cross-sectional view for explaining another structure of the projection unit, which is an example in which an optical fiber is used for introducing a light beam.

FIG. 10 is a schematic view showing an example of a conventional under-horizontal light shielding device attached to each projection unit.

FIG. 11 is a schematic view showing another example of a conventional horizon under-light shielding device.

[Explanation of symbols]

2a to 2f, 23a to 23d, 24a to 24d, 38a
˜38b Projection unit 4 Diurnal axis 5, 15a, 15b Mirror light source lamp 6, 32a, 32b Mirror 7 Stellar sphere 8 Dimmer element 9, 31a, 31b Concave lens 10 Convex mirror 11 Power source device for light source 12 Control circuit 13 Focus position 18a, 18b Dimmer element 19a, 36 Lens 21a, 21b Power supply device 22a, 22b Control device 33a, 33b Prism 34a Northern star sphere 34b South star sphere 35 Luminous flux 37a-37c, 39a-39j Emission configuration surface

Claims (7)

[Claims] 1. A star projector for a starry sky in a planetarium for projecting a starry sky by a star projection sphere including a plurality of projection units, wherein a light beam emitted from a light source placed outside the star projection sphere is
A divergent light is guided through the hollow rotation axis into the star projection sphere, and is refracted or reflected by an optical unit composed of a lens having a negative refractive power or a reflecting mirror having a convex surface, which is arranged near the center of the star projection sphere. The stellar projector is characterized in that each ray direction of the divergent light is aligned with the optical axis of the plurality of projection units to uniformly illuminate the projection plane of the star field. 2. The star projector according to claim 1, wherein a surface of a lens having a negative refractive power or a reflecting mirror having a convex surface arranged near the center of the star projection sphere is constituted by a plurality of flat surfaces or curved surfaces. By arranging the lens or the reflecting mirror and the projection units so as to guide the respective light ray directions of the divergent light diverged on these planes only to the directions in which the projection units exist, the projection units are efficiently arranged. A stellar projector characterized by directing light rays. 3. The star projector according to claim 1 or 2, wherein an output light beam from a light source is guided through a rotation axis that is orthogonal to the rotation axis of the star projection sphere and has a function of tilting the star projection sphere, and a mirror or A star projector characterized by using a prism to guide the light to the center of the rotation axis of the star projection sphere and efficiently guide light to each projection unit. 4. The stellar projector according to claim 3, wherein two sets of the stellar projectors are combined so as to face each other, thereby eliminating a projection dead angle due to a rotation axis and projecting the whole sky. Stellar projector characterized by. 5. The star projector according to claim 1, 2, 3 or 4, wherein a dimming element capable of changing optical density is arranged in an optical path from the light source to change a projected light intensity of a star. A stellar projector characterized in that 6. The stellar projector according to claim 5, wherein the light control element is an element capable of varying a density or a transmittance in an arbitrary pattern or a reflectance or a reflection angle in an arbitrary pattern. , A stellar projector characterized by making it possible to change the projected luminosity of a star in an arbitrary pattern. 7. The star projector according to claim 6, wherein the light control element is a liquid crystal element, a movable shutter, or a DMD.
A stellar projector characterized by being an element.