JPS5941161B2 - Lamp unit with controlled diffuse reflector and method for manufacturing the reflector - Google Patents

Abstract

For a lamp unit, a sagged glass reflector having a stippled, concave surface for providing controlled diffusion of light. The method of making the reflector comprises: providing a preheated concave mold having a uniform pattern of peened indentations in its surface and a plurality of vacuum drawing holes; placing a flat blank of glass across the opening of the mold; heating the glass to a plastic state; drawing a partial vacuum in the mold to force the plasticized glass to sag against the peened surface of the mold; cooling the glass to a rigid state; and applying a coating of reflective material on the concave surface of the sag-molded glass.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lighting device using a reflecting mirror with a lamp, and more particularly to a reflecting mirror that can control the diffusion of light and a method for manufacturing the reflecting mirror.

Controlling the diffusion means averaging the beam pattern without compromising the distribution of the initial three-dimensional light flux from the lamp, and obtaining a diffusion that eliminates the filament image. Reflectors having the above-described diffusion properties are useful in a variety of devices, such as floodlights and condensing devices in movie projectors. If the material can be processed, such as aluminum, the reflector can be made by spinning, electrolysis,
It can be made by fluid force, bursting, punching, etc.

Glass reflectors have been made by blowing glass into a mold, letting it sag (drop) by gravity, or press-fitting glass into a two-panel mold, but they are cheap and available in large quantities. It is not suitable to grind or polish a raw aspherical material. For reliable light control, the reflective mirror surface must be completely flat. However, in reality,
It is necessary to correct the uneven light distribution by spreading the light rays from each point on the reflecting mirror surface and creating a conical beam. In the commonly used diffusion techniques such as etching and sandblasting, diffusion cannot be suppressed, and the particles are diffused at angles as large as 2π steradians. Appropriate control can be achieved by providing a number of closely spaced small (relative to the entire mirror) sections on the mirror surface with curvatures different from that of the mirror. This small portion has conventionally been achieved by machining the reflective surface using tools. In this way, this technique was used for the metal reflector mentioned above and the reflector made by processing glass. Glass reflectors with controlled diffusion are particularly advantageous when the temperature of the light beam has to be reduced.

A glass reflector coated with cold dikreuzumira reflects visible light, but allows most infrared light to pass through. Such beam separation techniques are not possible with metal reflectors. The best that can be done with a metal reflector is to have the reflective surface coated with dichroic mirror absorb infrared rays, but doing so causes a local temperature rise on the reflective surface. However, the value of this dichroic mirror coating is not fully recognized at present. As an example of considering a reflector that diffuses light and the problems associated with it, there is a case where a lamp and a reflector are integrated.
5m77! Consider a reflective condensing system for a slide projector.

Such a collection system includes a lamp assembly having an objective lens, a film gate aperture, a relay lens, and a reflector. When a conventional projection 4-inch, f-3.5 objective lens and a relay lens of about 15 diopters near the optical axis are used in a normally spaced array, the reflection Mirror light collection systems require controlled light that is spread within a certain solid angle to prevent local inhomogeneities on the screen. Conventionally, for this purpose,
They used pressurized reflectors that were attached to expensive base sockets or heavy pressurized reflectors that were attached to the rim. When a tool is used to make a notch on the reflective mirror surface, the size of each lamp unit changes due to wear of the tool. Also, because its structure is extremely fine, it is difficult to make many similar ones. Recognizing the shortcomings of the above-mentioned known techniques, the main objective of the present invention is to provide a lighting device with improved controlled diffused light.

A further object of the invention is to provide a reflector made of glass or similar material which is stippled over almost its entire surface in order to obtain controlled diffused light.

A further object of the invention is to provide an improved method of making such a reflector.

In the present invention, when a plastic material such as glass is sagged into a concave mold having a stippled surface, and the sagged concave surface is coated with a reflective material, the curved surface of a normal reflective mirror is It has been found that it is possible to obtain a reflector that provides controlled diffused light having a controlled portion with increased or decreased curvature. The saturging process involves molding a material such as glass in a plastic state so that the mold contacts only the surface opposite to the surface that will ultimately be subjected to reflection.
It involves the process of pouring into a stippled mold surface using gas pressure and/or gravity. In this way, the finished reflective surface will not be scratched by contact with tools or the like. The stippled reflecting surface also reflects diffused light falling within a certain space from each point of the reflecting mirror. The reflector according to the invention is produced by inserting a heated and softened raw material, generally glass, into a mold using gravity and/or the differential pressure between the area between the glass and the mold and its surroundings. Made. The mold differs in thickness from the finished mirror surface by an amount that takes into account the thickness of the glass, which varies with the amount of glass inflow. Small deformations called stippling are made on the surface of the mold to correct the mirror surface. Generally, the stipples are concave spherical notches on the die surface, but spheroidal, ellipsoidal, flat, or non-conical indentations may also be made. Convex stipples can also be used. The size and shape of the portion containing the stippling or peen is defined. The parts are also arranged in a certain way so that the total spread of light emanating from each part is controlled and convenient for making copies from the mold. The size of the peen is determined by the tool used to make the peen (for example, in the case of a spherical peen, the radius of the spherical surface of the tool) and the average radius of the surface on which the peen is applied. How to create a reflective soil peen depends on how much light rays are spread in a particular direction.

With aluminum, silver, interference filters and other reflective materials,
The reflective surface that is finally coated is susceptible to scratches and other irregularities when the peen is formed using a tool. A projection lamp using a reflector according to the invention is shown in FIGS. 1 and 2.

The spheroidal reflecting mirror 10 has a dichroic cold mirror on its inner conical surface having stippling or peen for controlling projection light. The large peen on the convex surface 14 is made directly from the female mold. The lamp base 16 is used to fixedly support the lamp within the reflector. Lamp 18 is most commonly a tungsten halogen lamp with an incandescent filament. This lamp 18 is also inserted from the top of the reflector. The lamp is located within or in the immediate vicinity of the space defined by the reflective mirror surface 12 and the aperture surface. A typical sagging process is illustrated in FIG.

In this figure, a central cross-section of a mold for making a stippled reflector according to the invention by sagging is shown. The concave surface 24, which forms the outer surface of the reflector during sagging, is stippled, indicated by notches 26, to obtain the desired shape. It is preferable that this stippling is performed according to a certain pattern. The mold surface 24 is therefore provided with spherical indentations following a substantially uniform pattern. To create a vacuum between the mold and the sagged glass, the stippling surface has a number of small holes, approximately 0.051 cm (0.020 inch) in diameter, typically hole 28. Illustrated by. In the central convex part of the mold, the glass is thinned and a central hole 20 (FIG. 2) of the reflector is provided there. The shape of this convex portion is not very important. The small deformation at the top of the mold is determined by the way the glass is shaved and finished after molding. Preferred embodiments of the present invention will be described below.

The Dojo mold is first preheated to between 1100 and 1200°C. Next, a flat glass blank 32 is placed over the preheated mold 22 with sufficient margin to form a tight seal. Generally, the glass used for raw material is approximately 0.1
78 cm (0.07 inch) thick, 0-300°C
The composition consists of conventional soda-lime glass having an average coefficient of thermal expansion of 87 to 93.times.10@-7 / DEG C. Instead of glass, the green material 32 can also be made from other rigid materials that have a plasticity after heating that is suitable for mirror formation. next,
The glass is heated to a plastic state and allowed to sag under gravity, while the holes 28 are used to create a vacuum between the green glass and the mold. In this way, the plasticized glass can be sagged into a stippled surface without tools, and the glass can be made into a stippled concave surface without tools. By creating a vacuum state, the problems that tend to occur when using only gravity-based suction,
This will prevent gaps from forming between the glass and the mold. As the most common manufacturing method, the above-mentioned process is carried out by placing several molds on a conveyor and passing them through a furnace adjusted to 1100-1200°C. The shaped glass is cooled until it becomes solid.

FIG. 4 is a partial cross-sectional view showing changes in the thickness of the molded glass 34.

The central portion 36 created by the protrusion 30 is cut away around the point 38 to create the hole 20. An enlarged view of area 40 of the glass cross section is shown in FIG. The convex outer surface 42 is created by direct contact with the mold;
On the other hand, the stippled portion 26 having a small optical effect is formed on the inner surface 44 by the flow of plastic glass. The inner surface of the glass 44 is molded with a thin reflective material such as aluminum.
It is coated to reflect light. Coating 44 can be a cold dichroic mirror coating that reflects visible light from the incandescent filament of lamp 18 and transmits infrared light toward the back of the reflector.

The basic model (first model) of a reflector suitable for the 35mm projector mentioned above.
Figures 2 and 2) have a major axis of 3.655 cm (1.4 cm).
It is part of an ellipsoid of revolution with a minor diameter of 2.342 cm (0.922 inch).

The female mold 22 for this reflector has a glass thickness of 0.0 at the apex.
61 centimeters (0.024 inches), with the glass thickness increasing by 0.097 centimeters (0.038 inches) every 2.54 centimeters (1 inch) as you move away from the apex along the major axis. It is being created. Therefore, the aforementioned spheroidal surface is cut by the aforementioned thickness. The actual value of this incision depends on the type and thickness of the flat glass blank used and on the temperature distribution during the sagging process, the time required and the pressing equipment. 32 vacuum creation holes 28 to create a uniform vacuum state
are arranged arbitrarily on the mold surface. The degree of beaning is subjective, as there is no specific relationship between peening and uniform light without unwanted bands, concentrations, or other striations. The uniformity of each point on the projection screen, expressed as the ratio of corners to center, is not the primary factor determining the degree of peening. The required amount of diffusion provided by peen processing was determined by experts who agreed on the tolerances of the projection equipment. In this way, tolerances are generally determined. Considering that the optical effect of the peen on the front side of the reflective surface is reduced due to the flow of plastic glass over the peen of the mold, the peen on the rear side of the reflective surface is placed on the mold by 1.586 cm. 0.625 inches) and an average circumferential diameter of 0.152 centimeters (0.060 inches). In this way,
Concave spherical stipples 26 can be provided in a substantially constant pattern on the concave surface of the sagged glass. The function of the stipple or peen is illustrated in FIG.

Consider a beam of light 48 that is incident on a smooth reflective surface 50. If the reflected pencil ray 52 is unpeened, there will be substantially no change in diffusion upon reflection. When there is a non-uniformity in brightness, such as in a coiled incandescent filament, this non-uniformity is accompanied by an "image" in the broad sense of the word, causing an undesirable non-uniform light surface. When the pin 54 is at the point of reflection, the spread of the reflected pencil ray is large, such as at a solid angle 56. In this way, partial reflections in the system can be eliminated. However, the incident pencil ray is still reflected within a solid angle. If global diffusion were to be used, the reflected light would be spread out over a large solid angle approaching 2π steradians, thus reducing or eliminating the mirror's directional control ability. . Therefore, the stipples that reflect light within a solid angle are provided on the reflective surface of the sagged glass,
Useful for improved directional control in devices such as floodlights or projection lamps. In summary, the present invention provides a three-dimensional reflector in which plasticized glass or similar material is poured into a mold by gravity and/or glass pressure.
This invention relates to a three-dimensional reflector in which the surface in contact with the mold is located at a position opposite to the reflective surface, and the reflective surface is coated with a reflective material such as aluminum.

Furthermore, there is a method to control the degree of light spread by adding
It is provided by providing unevenness while maintaining the three-dimensional properties as a whole. Reflectors are commonly used to control light in conjunction with, or as an integral part of, a lamp or light source. The process by sagging has special advantages in various cases. The finished reflective surface is not subject to tool contact. However, if the original surface is of good quality, its quality will not deteriorate even if it comes into contact with six tools. Methods of manufacturing reflectors of a certain size and shape have economic advantages over other methods. Furthermore, the use of stippled and sagged glass to control the diffusion of the reflector is advantageous, especially with regard to thermal control and heat resistance. That is,
Glass allows the use of dichroic coatings that can reduce the heat of the beam without the localized temperature increase that occurs with metal reflectors.
Also, by using the sagging process, glass can be made much thinner than normally required for pressed glass. For example, the maximum thickness of a sagged glass reflector is well over 0.1 inch. In contrast, the thickness of pressurized glass reflectors is typically 0.25
It is considerably larger than 4 centimeters (0.1 inch), for example about 0.457 centimeters (0.18 inch). Thin glass has strong heat resistance, so reflective mirrors using sagging are cheaper. It can be made from a glass with a higher expansion coefficient, such as ordinary soda-lime glass. Furthermore, the reflector according to the present invention obtained by processing glass or plastic by suction method has a wall thickness that decreases as it approaches the light source and is coated with a cold mirror coating, so that infrared rays near the light source are It has good permeability and excellent heat resistance. Due to their lower heat resistance, thicker fabricated glasses typically use more expensive materials with lower expansion coefficients, such as borosilicate glasses, to increase their heat resistance. Although the invention has been made with respect to particular embodiments, it should be noted that variations therein can be made by those skilled in the art without departing from the spirit and scope of the invention.

[Brief explanation of the drawing]

Fig. 1: A perspective view of a lamp unit having a reflector by sagging according to the present invention, Fig. 2: A front view of the lamp unit of Fig. 1, Fig. 3: Fabrication of the reflector of Figs. 1 and 2. A schematic cross-sectional view of the mold used for this purpose, Fig. 4; a partial cross-sectional view of the molded glass in the reflector of Figs. 1 and 2, Fig. 5; A partially enlarged view of the cross-sectional view of the reflecting mirror in FIG. 4. FIG. 6: A diagram showing the optical effect of the pin on the reflecting surface. The main components and reference numbers in the figures are as follows. 10: Spheroidal reflector, 18: Lamp, 22: Mold, 26
: Stipple, 32: Unprocessed material.

Claims (1)

[Claims] 1. An object made of glass or plastic with a concave surface formed by saturation so as to produce a stipple effect over almost the entire surface, and a cold mirror coating of a reflective object applied on the concave surface. It is a reflecting mirror for projecting controlled diffused light, and the object formed by the saturation becomes thinner toward the center, and the surface side has a plurality of concave spherical surfaces due to the stipple effect. A reflecting mirror comprising a concave surface and a concave surface on the back side having a plurality of protrusions corresponding to the concave spherical surface.