JP2000306402A - Light source unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source unit realizing extension of its service life by simply and surely preventing a reflector of a light-transmitting plate from cracking and enabling the light-transmitting plate to be surely positioned relative to a luminous tube fixed to the reflector. SOLUTION: In this light source unit U, a light-transmitting plate 20 is fixed to a reflector R being fitted into a groove part 22, thereby covering an opening part of the reflector R, and thus a structure suitable for explosion-proof is obtained. At the time of fixing, a side wall surface 22b of the groove part 22 is spaced apart from the side surface 20c of the light-transmitting plate 20. Even in the cases where the reflector R differs from the light-transmitting plate 20 in the amount of thermal expansion, the space can provide an appropriate escape for stresses. When the light-transmitting plate 20 is fitted into the groove part 22, a bottom wall surface 22a of the groove part 22 is brought into direct contact with a back surface 20d of the light-transmitting plate 20, thereby surely defining positional relation between a luminous tube and the light-transmitting plate 20 in the tube axis direction of the luminous tube. This is effective especially in the cases where the light-transmitting plate 20 is a lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source unit having a discharge tube for generating light of a predetermined wavelength by light emission of an arc, and a reflector for reflecting light from the discharge tube and emitting light in a predetermined direction. It is about.

[0002]

2. Description of the Related Art Conventionally, as techniques in such a field, there are JP-A-8-511902 and JP-A-4-263201. The light source units described in these publications are:
A transparent plate is fixed to the periphery of the opening of the reflector so that the lamp is fixed inside the reflector and the opening of the reflector is closed.

[0003]

However, the above-mentioned conventional light source unit has the following problems. That is, a transparent plate is fixed to the peripheral portion of the opening of the reflector via an adhesive, and the transparent plate is fitted so as to fit exactly into an L-shaped notch groove provided in the peripheral portion of the opening. In this case, the opening of the reflector is covered with the transparent plate, and the high heat generated from the arc tube exposes not only the reflector but also the transparent plate to a high temperature, and the air inside the reflector keeps maintaining an extremely high temperature. Will be. As a result, at the time of light emission, if the transparent plate thermally expands due to high heat, one or both of the reflector and the transparent plate bonded via an adhesive may be broken, and the light source unit has a long service life. This was a problem in achieving the goal.

The present invention has been made to solve the above-mentioned problems, and in particular, a light emitting device fixed to a reflector while easily and reliably preventing a reflector or a light transmitting plate from cracking and extending its life. An object of the present invention is to provide a light source unit capable of reliably positioning a light transmitting plate with respect to a tube.

[0005]

According to a first aspect of the present invention, there is provided a light source unit having a hollow light-emitting portion for accommodating a pair of discharge electrodes for generating an arc in a state where the discharge electrodes face each other. An arc tube having a pair of front and rear sealing portions and a rear sealing portion provided, a glass reflector to which a rear end portion of the arc tube is fixed, and a light transmitting portion provided at an opening end of the reflector. A plate housing portion, comprising a light-transmitting plate made of glass material and fixed to the light-transmitting plate housing portion, the light-transmitting plate housing portion,
A groove is provided on the periphery of the opening to accommodate the light-transmitting plate, and the groove is formed by a bottom wall surface extending in the radial direction at the opening periphery and a side wall surface extending in the tube axis direction of the arc tube. The side wall surface of the groove and the side surface of the light transmitting plate are separated from each other, and the bottom wall surface of the groove and the back surface of the light transmitting plate are in contact with each other.

In this light source unit, when the light-transmitting plate is fixed to the reflector so as to be fitted into the groove, the opening of the reflector is covered with a lid, which is a structure suitable for explosion-proof. At the time of the fixing, the side wall surface of the groove is separated from the side surface of the light transmitting plate. As a result, even if the amount of thermal expansion between the reflector and the translucent plate is different, relief of stress can be appropriately created by the gap. Furthermore, when fitting the light-transmitting plate into the groove, the bottom wall surface of the groove is brought into direct contact with the back surface of the light-transmitting plate, so that the positioning of the light-emitting tube and the light-transmitting plate in the tube axis direction of the light-emitting tube is ensured. Something. This is particularly effective when the light transmitting plate is a lens.

In the light source unit according to the second aspect, it is preferable that the projection provided on the back surface of the light-transmitting plate abuts against the bottom wall surface of the groove. Such a protrusion can reduce the contact area when the light-transmitting plate is brought into contact with the reflector, and contributes to improving the positioning accuracy of the light-transmitting plate with respect to the reflector.

[0008] In the light source unit according to the third aspect, it is preferable that a concave portion for filling with an adhesive is provided on the back surface of the light transmitting plate. With this configuration, as a result of filling the concave portion with the adhesive, the reflector and the light transmitting plate can be securely connected on the bottom wall surface side of the groove while directly contacting the bottom wall surface of the groove and the back surface of the light transmitting plate. Can be bonded and fixed.

In the light source unit according to the fourth aspect, it is preferable that a concave portion for filling the adhesive is provided on a side surface of the light transmitting plate. With this configuration, as a result of filling the concave portion with the adhesive, the reflector and the light transmitting plate can be securely bonded and fixed on the side wall surface side of the groove portion.

[0010] In the light source unit according to the fifth aspect, it is preferable that a cutout portion for filling the adhesive is provided in a corner portion formed by the side surface and the back surface of the light transmitting plate. With this configuration, the adhesive can be arranged at the corners of the light transmitting plate, and the reflector and the light transmitting plate can be securely bonded and fixed.

In the light source unit according to the present invention, it is preferable that an adhesive is disposed in a part of a gap formed by separating a side wall surface of the groove from a side surface of the light transmitting plate. In this case, the gap is not completely filled with the adhesive, but a part of the gap is filled with the adhesive while maintaining the gap between the side wall surface of the groove and the side surface of the light transmitting plate.

[0012] In the light source unit according to claim 7, the light transmitting plate is preferably a glass lens member. In this case, a lens member for generating a desired light beam while refracting the arc light in a desired direction is attached to an opening peripheral portion of the reflector. As a result, the reflector and the lens are integrated, and the compactness of the light source unit is promoted.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a light source unit according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing a light source unit according to the present invention. The light source unit U shown in the figure has a reflector R having a reflection surface on the back surface, and a mercury-xenon lamp 1 as an example of an arc tube is fixed to the reflector R. As shown in FIG. 2, the mercury xenon lamp 1 includes a bulb 2 made of glass (for example, quartz) or ceramics (for example, translucent ceramics).
The bulb 2 has a hollow light emitting portion 3 having a substantially elliptical sphere at the center, and a gas such as mercury is sealed inside the light emitting portion 3.

Further, the bulb 2 has a pair of sealing portions 4 and 5 extending from both sides of the light emitting portion 3, and when the bulb 2 is mounted on the reflector R, the sealing portion 4 becomes the rear side and the reflector R And the sealing portion 5 is placed in a free state in the reflector R with the front side thereof. Further, thin metal foils 7 and 6 made of molybdenum are sealed in the front sealing portion 5 and the rear sealing portion 4, and one end of the metal foil 6 has one direction in the light emitting portion 3. Discharge electrodes 8 projecting from the metal foil 6 are electrically connected to each other, and a first lead wire 9 exposed from the rear end of the sealing portion 4 is electrically connected to the other end of the metal foil 6.

Similarly, the discharge electrode 1 is provided on one end of the metal foil 7.
The second lead wire 11 exposed from the front end of the sealing portion 5 is electrically connected to the other end of the second lead wire 11. A metal base 12 is fixed to the rear end of the rear sealing portion 4 of the bulb 2, a first lead wire 9 is electrically connected to the base 12, and the base 12 is connected to the reflector 12. Fixed to R. And the male screw part 13 of the base 12
The second lead wire 11 is connected to an external power supply circuit (not shown) to generate a predetermined arc discharge between the discharge electrodes 8 and 10.

As shown in FIG. 1, a glass lens member 20, which is an example of a light-transmitting plate, is fixed to the opening end of the glass reflector R via an adhesive S.
The lens member 20 is formed as a concave lens whose thickness decreases from the outer periphery of the circle toward the center. That is, on the back surface 20d side of the lens member 20, a spherical concave surface 20B concentric with the tube axis L of the arc tube 1 is provided.

Therefore, the light reflected by the reflector R can be emitted as parallel light, and the lens member 20 and the reflector R can be integrated, and the light source unit U can be made more compact. Note that the lens member 2
For 0, borosilicate glass is generally used, but heat resistance,
In some cases, quartz glass having impact resistance is used.

The lens member 20 and the reflector R
As a means for easily integrating with the adhesive S
At the opening end of the reflector R, a light-transmitting plate housing 21 for receiving the peripheral portion 20A of the lens member 20 is formed. A groove portion 22 having an L-shaped cross section for fitting the lens member 20 is provided in an opening peripheral portion A of the light transmitting plate housing portion 21. It is formed over the entire circumference. Further, when the light-transmitting plate housing 21 is formed small, the groove 22 is made shallow, and the lens member 20 is made to protrude greatly from the light-transmitting plate housing 21.
The exposed surface area of the lens member 20 increases, and the cooling efficiency of the lens member 20 improves.

As shown in FIG. 3, the groove 22 has a bottom wall surface 22a extending in the radial direction at the opening of the reflector R.
And the side wall surface 22b of the arc tube 1 extending in the direction of the tube axis L, so as to form an L-shaped cross section. While the side surface 20c of the lens member 20 and the side wall surface 22b of the groove 22 are separated by a predetermined dimension (for example, about 1 to 2 mm) over the entire circumference of the groove 22, the bottom wall surface 22a of the groove 22 and the lens member 2 are separated.
0 is brought into contact with the back surface 20d.

Then, as shown in FIG.
The adhesive S is filled in a desired portion of the gap B formed between the side surface 20c of the “0” and the side wall surface 22b of the groove 22, and the lens member 20 is fixed to the reflector R. in this case,
Instead of completely filling the annular gap B with the adhesive S, the side wall surface 22 b of the groove 22 and the side surface 2 of the lens member 20 are not filled.
The gap B is partially filled with the adhesive S while maintaining a gap between the gap B and the gap 0c. In this case, there are three places where the adhesive S is filled.

When the lens member 20 is bonded and fixed to the opening peripheral portion A of the reflector R in this manner, the flat plate 2
0 means that the opening of the reflector R is covered, and the configuration is suitable for explosion proof. Further, by actively creating a gap B between the side surface 20c of the lens member 20 and the side wall surface 22b of the groove 22, the reflector R and the lens member 20 are formed.
Even if the amount of thermal expansion is different, the clearance can be appropriately created by the gap B.

Further, at the time of light emission, the amount of thermal expansion of the adhesive S is larger than the amount of thermal expansion of the reflector R and the lens member 20, so that the adhesive S is filled between the reflector R and the lens member 20 at random. Then, the lens member 20 is displaced due to the expansion of the adhesive S, and this causes a reduction in the light collection efficiency of the lens member 20.

Therefore, when fitting the lens member 20 into the groove 22, the bottom wall surface 22a of the groove 22 and the back surface 20d of the lens member 20 are brought into direct contact. As a result, the arc tube 1 and the lens member 20 can be reliably positioned in the tube axis L direction (optical axis direction). This is because the adhesive S is not interposed when the bottom wall surface 22a of the groove 22 and the back surface 20d of the lens member 20 are brought into contact with each other. Such means is particularly effective when the light source unit U is used for a projection device such as a liquid crystal projector.

The present invention is not limited to the embodiment described above. Note that the same or equivalent components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 5 and 6, in the first modification, the outermost periphery of the back surface 30d of the lens member 30 has
A projection 31 is provided for projecting a part of the back surface 30d in the optical axis direction to form a step. The rear surface 30 d of the lens member 30 and the bottom wall surface 22 a of the groove 22 are in contact with each other via the protrusion 31.

Such projections 31 are provided on the entire circumference of the lens member 30 and reduce the contact area of the lens member 30 with the bottom wall surface 22a of the groove 22. As a result, the positioning accuracy of the lens member 30 with respect to the reflector R can be improved. Then, when the lens member 30 and the reflector R are bonded and fixed, the adhesive S is filled into the gap C formed between the rear surface 30d and the bottom wall surface 22a by the projection 31. The side surface 3 of the lens member 30
The adhesive S may be filled in a predetermined portion of the gap B provided between the groove 0c and the side wall surface 22b of the groove portion 22.

As shown in FIGS. 7 and 8, in the second modification, an elliptical adhesive filling recess 41 is provided on the back surface 40d of the lens member 40. Recess 41
Are formed at equal intervals in the circumferential direction of the back surface 40d. As a result of filling the recesses 41 with the adhesive S, the bottom wall surface 2a of the groove 22 is directly contacted with the bottom wall surface 22a of the groove 22 and the back surface 40d of the lens member 40.
On the 2a side, the reflector R and the lens member 40 can be securely bonded and fixed. It should be noted that the adhesive S may be filled in a predetermined portion of the gap B provided between the side surface 40c of the lens member 40 and the side wall surface 22b of the groove 22. Further, the concave portion 41 may be provided over the entire circumference.

As shown in FIGS. 9 and 10, in the third modification, a concave portion 51 for filling with an adhesive is provided on a side surface 50c of the lens member 50. The concave portion 51 is provided on the side surface 50.
6 are formed at equal intervals in the circumferential direction of c. As a result of filling each recess 51 with the adhesive S, the groove 2
The reflector R and the lens member 50 can be securely bonded and fixed on the side of the side wall surface 22b of the groove portion 22 while directly contacting the bottom wall surface 22a of the second and the rear surface 50d of the lens member 50. Further, the concave portion 51 may be provided over the entire circumference.

As shown in FIGS. 11 and 12, in the lens member 60 of the fourth modification, a notch 61 for filling the adhesive is formed at a corner portion formed at right angles between the side surface 60c and the back surface 60d. Is provided. The notch 61
Three portions are formed at equal intervals in the circumferential direction of the corner portion. As a result of filling the notch 61 with the adhesive S, the reflector R and the lens member 60 are securely bonded and fixed while the bottom wall surface 22a of the groove portion 22 and the back surface 60d of the lens member 60 are brought into direct contact. Can be done. The side surface 60c of the lens member 60 and the side wall surface 2 of the groove 22
2b at a predetermined position of the gap B provided between the adhesive S
May be filled. Also, the notch 6
1 may be provided over the entire circumference.

[0031]

Since the light source unit according to the present invention is configured as described above, the following effects can be obtained. In other words, it has a hollow light emitting portion that accommodates a pair of discharge electrodes that generate an arc in a state of facing each other, and a pair of front and rear sealing portions provided on both sides of the light emitting portion. An arc tube, a glass reflector to which the rear end of the arc tube is fixed, a light-transmitting plate housing provided at the opening end of the reflector, and a glass material and fixed to the light-transmitting plate housing. A light-transmitting plate, wherein the light-transmitting plate housing portion has a groove provided on an opening peripheral portion of the reflector to receive the light transmitting plate, and the groove portion extends radially in the opening peripheral portion of the reflector. The groove is formed from a wall surface and a side wall surface extending in the direction of the tube axis L of the arc tube. The side wall surface of the groove is separated from the side surface of the light transmitting plate, and the bottom wall surface of the groove and the back surface of the light transmitting plate are abutted. By doing so, easily and reliably prevent cracking of the reflector or translucent plate, While achieving life, it is possible to reliably position the transparent plate with respect to the arc tube fixed to the reflector.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a light source unit according to the present invention.

FIG. 2 is a front view showing an arc tube applied to the light source unit.

FIG. 3 is an enlarged sectional view of a main part of the light source unit shown in FIG.

FIG. 4 is a front view of the light source unit shown in FIG.

FIG. 5 is a rear view showing a first modification of the lens member.

FIG. 6 is an enlarged sectional view of a main part of a light source unit to which the lens member of FIG. 5 is applied.

FIG. 7 is a rear view showing a second modification of the lens member.

8 is an enlarged sectional view of a main part of a light source unit to which the lens member of FIG. 7 is applied.

FIG. 9 is a rear view showing a third modification of the lens member.

FIG. 10 is an enlarged sectional view of a main part of a light source unit to which the lens member of FIG. 9 is applied.

FIG. 11 is a rear view showing a fourth modification of the lens member.

FIG. 12 is an enlarged sectional view of a main part of a light source unit to which the lens member of FIG. 11 is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Arc tube, 3 ... Light emitting part, 4 ... Rear sealing part, 5 ... Front sealing part, 8, 10 ... Discharge electrode, 20, 30, 40, 50,
60 ... Lens member (light transmitting plate), 20c, 30c, 40
c, 50c, 60c... side surfaces of the light transmitting plate, 20d, 30d,
40d, 50d, 60d: the back surface of the light-transmitting plate, 21: the light-transmitting plate housing portion, 22: the groove portion, 22a: the bottom wall surface of the groove portion, 22b ...
Side wall surface of groove portion, 31: Projecting portion, 41, 51: concave portion for filling with adhesive, 61: cutout portion for filling with adhesive, U: light source unit, R: reflector, A: peripheral portion of opening, B: gap, S …
Adhesive, L ... tube shaft.

Claims (7)

[Claims] 1. A hollow light emitting portion for accommodating a pair of discharge electrodes for generating an arc facing each other, and a pair of front and rear sealing portions provided on both sides of the light emitting portion. A light-emitting tube having a rear end portion of the light-emitting tube fixed thereto; a light-transmitting plate accommodating portion provided at an open end of the reflector; and a light-transmitting plate made of glass material. A light-transmitting plate fixed to the housing portion, wherein the light-transmitting plate housing portion has a groove provided in the opening peripheral portion to receive the light transmitting plate, and the groove portion is provided in the opening peripheral portion. A bottom wall surface extending in a radial direction and a side wall surface extending in a tube axis direction of the arc tube, separating the side wall surface of the groove from a side surface of the light transmitting plate, and forming a bottom of the groove; A light source unit wherein a wall surface and a back surface of the light transmitting plate are in contact with each other. 2. The light source unit according to claim 1, wherein a projection provided on the rear surface of the light transmitting plate is in contact with the bottom wall surface of the groove. 3. The light source unit according to claim 1, wherein a concave portion for filling an adhesive is provided on the rear surface of the light transmitting plate. 4. The light source unit according to claim 1, wherein a concave portion for filling an adhesive is provided on the side surface of the light transmitting plate. 5. The light source unit according to claim 1, wherein a notch portion for filling an adhesive is provided in a corner portion formed by the side surface and the back surface of the light transmitting plate. 6. An adhesive according to claim 1, wherein an adhesive is disposed in a part of a gap formed by separating said side wall surface of said groove and said side surface of said light transmitting plate. The light source unit according to claim 1. 7. The light source unit according to claim 1, wherein the light transmitting plate is a glass lens member.