JP3026742B2 - Glass reflector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass reflector in which a lamp such as a halogen lamp is mounted on a central portion of a concave reflecting surface to constitute a light source of lighting equipment.

[0002]

2. Description of the Related Art As is well known, general lighting, spotlights, projectors, overhead projectors (OHP),
Lighting equipment such as liquid crystal projection uses a light source configured by mounting a lamp such as a halogen lamp or a short arc metal halide lamp on a central portion of a concave reflecting surface of a glass reflecting mirror. The light source used in these lighting devices uses a glass reflecting mirror to transmit infrared rays emitted from the lamp in the rear direction, making it difficult for heat to be trapped therein, and is relatively small.

[0003] The prior art of a light source and a glass reflector of these lighting devices will be described below with reference to FIGS. 7 and 8 for an OHP light source, for example. FIG. 7 is a side view of the light source, and FIG. 8 is a plan view of the glass reflecting mirror as viewed from the rear side.

Referring to FIGS. 7 and 8, a light source 1 used for an OHP is configured by mounting a halogen lamp 3 on a glass reflecting mirror 2. The glass reflecting mirror 2 has a concave reflecting surface 5 on the front side of a bowl-shaped main body 4 having an outer diameter of about 50 mm.
Are formed.

The halogen lamp 3 is fixed to the lamp mounting portion 6 of the main body 4 by an adhesive, and the glass material forming the main body 4 has a coefficient of thermal expansion of 34 to 50.
Hard glass, which is relatively large at × 10 ⁻⁷ cm / cm / ° C. and inexpensive, is usually used.

The light source 1 configured as described above is mounted on an OHP body (not shown) and is used while being air-cooled by a cooling fan (not shown).

However, in the above prior art,
The halogen lamp 3 has a power of 200 W or more, and the heat at the time of irradiation causes distortion in the main body 4 of the glass reflecting mirror 2, and the main body 4 may be cracked by applying a slight impact, and in some cases, There was a possibility that the main body 4 would be broken.

On the other hand, in recent years, in lighting equipment including OHP, in order to make an irradiated surface or an object to be illuminated brighter, lamps used in the equipment have been increased in wattage. . Following this, in the above-mentioned OHP, the halogen lamp 3 is being made to have a higher wattage.

However, if a high wattage one is used,
The calorific value of the halogen lamp 3 becomes extremely large, and the possibility that the main body 4 made of hard glass having a relatively large coefficient of thermal expansion is damaged is greatly increased. Under such circumstances, the coefficient of thermal expansion is 30 to 33 × 10 ⁻⁷ c so that thermal damage is reduced.
Heat resistant glass such as hard glass having a relatively small m / cm / ° C and crystallized glass having a low coefficient of thermal expansion is used.

These heat-resistant glasses having a low coefficient of thermal expansion are several times to several tens of times more expensive than hard glass having a relatively large coefficient of thermal expansion, and their use is limited to light sources for special purposes. It has not yet been used as a light source for general-purpose equipment.

For this reason, even when the lamp is made to have a high wattage by using a hard glass having a relatively large thermal expansion coefficient as in the light source 1 described above, a low-cost glass reflecting mirror which is less likely to be damaged is strongly realized. Is desired.

[0012]

When the light source is made to have a high wattage as described above, there is a high possibility that a conventional glass mirror made of hard glass having a relatively large coefficient of thermal expansion will be broken. When heat-resistant glass is used, the risk of breakage is reduced, but the cost is high. In view of such a situation, the present invention has been made, in which a heat radiation fin is formed on the back side of a main body formed using hard glass having a relatively large thermal expansion coefficient, and the temperature of the main body is lowered, so that it is difficult to be damaged. It is an object of the present invention to provide a low-cost glass reflector.

[0013]

The glass reflector according to the present invention has a concave reflecting surface on the front side of a hard glass main body, and a lamp mounting portion for fixing a lamp at a central portion of the main body. In the glass reflector configured to transmit light, the main body has a thermal expansion coefficient of the hard glass.
34 to 50 × 10 ⁻⁷ cm / cm / ° C.
From the lamp mounting part to the back part of the concave reflecting surface
Radiation fins formed integrally with the main body on the back side of
The radiation fins are further provided radially from the lamp mounting portion to the back surface of the concave reflection surface. Japanese that is provided in the annular from the mounting portion to the rear portion of the concave reflecting surface
It is a sign.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

First, a first embodiment will be described with reference to FIGS. 1 is a side view, FIG. 2 is a plan view seen from the back side, and FIG. 3 is a longitudinal sectional view of a light source using the glass reflecting mirror of the present embodiment.

1 to 3, reference numeral 11 denotes a glass reflecting mirror having a concave surface 13 forming a paraboloid of revolution on the front side of a bowl-shaped main body 12 having an outer diameter of about 50 mm, and having an opening in a forward direction. A flange 14 is formed at the outermost peripheral portion of the concave surface 13 thus formed. The concave surface 13 is provided with a reflective layer 15 on which a dielectric multilayer film is vacuum-deposited to form a concave reflective surface 16.

Further, a lamp mounting portion 17 having a substantially rectangular tube shape protrudes from the rear side of the central portion of the main body 12, and a lamp mounting hole 18 is formed in the lamp mounting portion 17. The main body 12 is provided on the outer wall surface of the lamp mounting portion 17 and the rear surface of the concave surface 13 projecting in the rear direction, and is provided in the lamp mounting portion 17 in the protruding direction. Eight heat dissipating fins 19 are radially arranged toward the end flange 14 so as to provide a substantially equal angle between adjacent heat dissipating fins.

The radiation fins 19 have a height of 2 mm at the lamp mounting portion 17 and an arrangement pitch of 4 mm.
The draft angle is about 10 ° and half of the height (1m in height)
The fin thickness at the position m) is 2 mm. On the back side of the concave surface 13, the height at a portion continuing to the root portion of the lamp mounting portion 17 is 2 mm, the height gradually decreases toward the flange 14, and the height becomes substantially zero at the flange 14 portion. It is provided as follows. Thus, the radiation fins 19 have a high fin formation density at the lamp mounting portion 17 and its root portion.

On the other hand, the main body 12 of the glass reflecting mirror 11 configured as described above has a thermal expansion coefficient of 34 to 50 × 10 ^−7.
It is formed by press molding using hard glass having a relatively large size of cm / cm / ° C. That is, although not shown, a groove for forming the radial radiating fins 19 in the lower mold of the molding die is cut and formed so as to correspond to the shape of the rear side including the projection shape of the lamp mounting portion 17 of the main body 12, Further, the upper mold is formed by cutting a shape corresponding to the concave surface 13 and the lamp mounting hole 18 and pouring molten hard glass into these molding dies and solidifying in the mold.

The reflection layer 1 is formed on the concave surface 13 of the main body 12.
5 to form a concave reflecting surface 16, and then the lamp mounting portion 1
A halogen lamp 20 is fixed to the glass reflecting mirror 11 in the lamp mounting hole 18 by an adhesive 22, and a light source 23 is formed. Reference numeral 24 denotes a bulb made of quartz glass or the like of the halogen lamp 20, reference numeral 25 denotes a tungsten filament sealed in the bulb 24, and reference numeral 26 denotes an external lead wire which is connected to the tungsten filament 25 drawn out of the sealing portion 21. is there.

Then, a halogen lamp 20 was mounted on the glass reflecting mirror 11 to form a light source 23, and the temperature was measured when the halogen lamp 20 was turned on. In the temperature measurement, the halogen lamps 20 having different power consumptions were measured with a thermal expansion coefficient of 37 × 1.
A plurality of light sources 23 are configured by being mounted on a glass reflecting mirror 11 formed of hard glass of 0 ^-7 cm / cm / ° C. After repeating the cycle for 10 cycles, the maximum temperature of the concave reflecting surface 16 side portion of the lamp mounting portion 17 was measured with a thermocouple.

At the same time, the occurrence of cracks in the glass reflector 11 was observed. In addition, for the measurement of temperature and observation of occurrence of cracks, for comparison, a halogen lamp with different power consumption was similarly attached to a glass reflector having a conventional configuration formed of hard glass having the same coefficient of thermal expansion, and each light source was used. The test was also carried out in the case of repeating the energization / disconnection by incorporating the power supply into the power supply. The results of temperature measurement and crack generation were as shown in the following table.

[0023]

[Table 1]

According to the results of temperature measurement and observation of crack generation, the power consumption of the halogen lamp is 2
At 50 W, fine cracks were observed, and the temperature was 50
When the temperature reaches 0 ° C. and the power consumption further reaches 300 W, cracks occur and the temperature reaches 580 ° C. On the other hand, according to the present embodiment, the power consumption of the halogen lamp is 300
In W, there is no abnormality and the temperature is 440 ° C., and when the power consumption becomes 350 W, the occurrence of minute cracks can be seen for the first time,
The temperature at this time reaches 510 ° C., and the power consumption is 40
At 0 W, cracks occur and the temperature reaches 590 ° C.

As a result, the glass reflecting mirror 11 of the present embodiment
, The temperature of the concave reflecting surface 16 side portion of the lamp mounting portion 17 becomes lower by about 100 ° C. to 150 ° C.,
Even when a halogen lamp 20 with a power consumption of 300 W is mounted, cracking due to thermal distortion is eliminated. In addition, it is possible to prevent the occurrence of injuries and the like due to cracking due to thermal strain, and it is possible to form the hard glass with inexpensive and easily available, thereby reducing the cost.

In general, the smaller the coefficient of thermal expansion, the higher the heat resistance, but the melting of the glass material and the molding temperature are increased, and the moldability is reduced. That is, the ability of the glass material to follow the mold becomes poor, and it is difficult to form a complicated and precise shape, and the production yield is low. On the other hand, when a hard glass having a relatively large thermal expansion coefficient of 37 × 10 ⁻⁷ cm / cm / ° C. is used, the melting and molding temperature of the glass material is low and the moldability is good, so that the heat radiation of a predetermined shape is achieved. It is easy to form the fins 19 and the heat load on the molding equipment is small,
Also, the production yield does not decrease.

The above-mentioned temperature measurement and the observation of the occurrence of cracks were performed using a glass reflector 11 made of hard glass having a thermal expansion coefficient of 37 × 10 ⁻⁷ cm / cm / ° C. Even in the case where the glass reflecting mirror 11 is formed using a hard glass included in the range of up to 50 × 10 ⁻⁷ cm / cm / ° C., substantially the same reduction in temperature and generation of cracks can be achieved.

Next, a second embodiment will be described with reference to FIGS. 4 is a side view, FIG. 5 is a plan view seen from the back side, and FIG. 6 is a longitudinal sectional view of a light source using the glass reflecting mirror of the present embodiment.

4 to 6, reference numeral 31 denotes a glass reflector having a concave surface 13 on the front side of a bowl-shaped main body 32 having an outer diameter of about 50 mm. A flange 14 is formed on the outer peripheral portion. The concave surface 13 is provided with a reflective layer 15 on which a dielectric multilayer film is vacuum-deposited to form a concave reflective surface 16. Further body 32
Has a substantially rectangular tubular lamp mounting portion 33 protruding from the rear side of the center portion thereof. The lamp mounting portion 33 has a lamp mounting hole 18 formed therein.

In the main body 32, three rectangular heat radiation fins 34 are provided on the outer wall surface of the lamp mounting portion 33 projecting in the rear direction so as to be arranged in the optical axis direction of the concave reflection surface 16. I have. Further, four annular heat radiation fins 35 are provided along the circumferential direction on the back surface of the concave surface 13 opened forward.
It protrudes from the base of the lamp mounting part 33 to the flange 14 at the opening end.

The radiation fins 34 of the lamp mounting portion 33 have a height of 2 mm and an arrangement pitch of 4 mm, and have a draft angle of about 10 ° and a half of the height (1 m in height).
The fin thickness at the position m) is 2 mm. Similarly, the height of the radiation fin 35 on the back surface of the concave surface 13 is 2 mm, the draft angle is about 10 °, and the height is ２ of the height (height 1).
mm), the fin thickness is 2 mm, the arrangement pitch dimension from the flange 14 side to the third fin is 6 mm, and the arrangement pitch dimension of the third and fourth fins is 4 mm.

The distance between the heat radiation fins 34 and the heat radiation fins 35 adjacent to each other at the base of the lamp mounting portion 33 is 4 m at the shortest distance between the corners of the lamp mounting portion 33.
m. As a result, the radiation fins 34 and 35 have a high fin formation density in the vicinity of the lamp mounting portion 33 and its base.

On the other hand, the main body 32 of the glass reflecting mirror 31 configured as described above has a coefficient of thermal expansion of 34 to 50 × 10 ^−7.
It is formed by press molding using hard glass having a relatively large size of cm / cm / ° C. That is, although not shown, the lower mold of the molding die is constituted by a split mold having a structure in which the lower mold is divided into two right and left, and a groove for forming the radiation fins 34 and 35 is formed in the lower mold of the split mold structure. 33 are cut out corresponding to the shape of the back side including the protruding shape of 33, and the shape corresponding to the concave surface 13 and the lamp mounting hole 18 is cut out in the upper die and melted in these forming dies. It is formed by solidifying hardened glass in a casting mold.

The reflection layer 1 is formed on the concave surface 13 of the main body 32.
5 to form a concave reflecting surface 16, and then the lamp mounting portion 3
The halogen lamp 20 is fixed to the lamp mounting hole 18 of the third by the adhesive 22 at the sealing portion 21 and is mounted on the glass reflecting mirror 31 to form the light source 36.

Then, similarly to the first embodiment, the halogen lamp 20 was mounted on the glass reflecting mirror 31 to form the light source 36, and the temperature when the halogen lamp 20 was turned on was measured. The temperature measurement was performed using a halogen lamp 20 with different power consumption.
Is mounted on a glass reflector 31 made of hard glass having a coefficient of thermal expansion of 37 × 10 ⁻⁷ cm / cm / ° C. to prepare a plurality of light sources 36, and these light sources 36 are respectively incorporated in an OHP for one hour. 1 cycle with 1-hour power interruption as one cycle
After the 0 cycle was repeated, the temperature of the portion of the lamp mounting portion 33 on the concave reflecting surface 16 side was measured.

At the same time, the occurrence of cracks in the glass reflecting mirror 31 was observed. The results of temperature measurement and crack generation were as shown in the table above. That is, according to the result of the temperature measurement and the observation of the occurrence of cracks, according to the embodiment,
When the power consumption of the halogen lamp was 300 W, there was no abnormality and the temperature was 450 ° C., and when the power consumption reached 350 W, fine cracks were observed for the first time.
When the temperature reaches 0 ° C. and the power consumption further reaches 400 W, cracks occur and the temperature reaches 600 ° C.

As a result, the glass reflecting mirror 31 of this embodiment
As in the first embodiment, the temperature of the concave reflecting surface 16 side portion of the lamp mounting portion 33 is 100 ° C.
It will be about 150 ° C lower. And power consumption 300
Even when the halogen lamp 20 of W is mounted, the occurrence of cracks due to thermal distortion is eliminated, and the occurrence of injuries and the like due to the occurrence of cracks can be prevented. Further, it is possible to form the glass reflecting mirror 31 with hard glass which is inexpensive and easily available, so that the cost can be reduced.

Further, since the glass material used is a hard glass having a relatively large coefficient of thermal expansion, it is easy to form the radiation fins 34 and 35 of a predetermined shape because of its good formability, and the heat load on the molding equipment And the production yield does not decrease.

The glass reflector 31 made of hard glass having a thermal expansion coefficient of 37 × 10 ⁻⁷ cm / cm / ° C. was used for the temperature measurement and the observation of the occurrence of cracks. In the case where the glass reflecting mirror 31 is formed using hard glass contained in the range of about 50 × 10 ⁻⁷ cm / cm / ° C., substantially the same reduction in temperature and generation of cracks can be achieved.

The heights, fin thicknesses, and arrangement pitch dimensions of the radiating fins 19, 34, and 35 in each of the above-described embodiments are exemplified in consideration of the heat radiating effect and formability, and may be appropriately changed. It can be implemented.

[0041]

As is apparent from the above description, the present invention provides a heat radiation fin on the back side of a hard glass body having a concave reflecting surface and a lamp mounting portion provided at the center to transmit infrared rays. With such a configuration, it is possible to reduce the temperature of the main body so that the main body is less likely to be damaged, and it is possible to easily reduce the cost.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment of the present invention.

FIG. 2 is a plan view of the first embodiment of the present invention as viewed from the rear side.

FIG. 3 is a longitudinal sectional view of the light source according to the first embodiment of the present invention.

FIG. 4 is a side view showing a second embodiment of the present invention.

FIG. 5 is a plan view of a second embodiment of the present invention as viewed from the rear side.

FIG. 6 is a longitudinal sectional view of a light source according to a second embodiment of the present invention.

FIG. 7 is a side view of a light source according to a conventional example.

FIG. 8 is a plan view of a conventional example viewed from the back side.

[Explanation of symbols]

 12, 32 body 16 concave reflection surface 17, 33 lamp mounting part 19, 34, 35 radiation fin

Claims (3)

(57) [Claims] 1. A glass having a concave reflecting surface on the front side of a main body made of hard glass and a lamp mounting portion for fixing a lamp at a central portion of the main body so as to transmit infrared rays. In the reflecting mirror, the main body is formed by heat of the hard glass.
When the expansion coefficient is 34 to 50 × 10 ⁻⁷ cm / cm / ° C.
In both cases, the rear part of the concave reflecting surface is from the lamp mounting part.
The heat sink formed integrally with the body on the back side
Glass reflector, characterized in that it comprises a fin. 2. The glass reflecting mirror according to claim 1, wherein the radiating fins are provided radially from the lamp mounting portion to the back surface of the concave reflecting surface. 3. The glass reflector according to claim 1, wherein the radiation fin is provided in an annular shape from the lamp mounting portion to the back surface of the concave reflection surface.