JPH10142468A - Light source device and method for assembling light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new light source device excellent in assembly and constituted to be more compact than the conventional light source device. SOLUTION: This device is provided with one or more light source elements 20, one or more coupling lenses 30 corresponding to the individual light sources and casings 10 and 12 integrally holding the elements 20 and the lenses 30; it emits luminous flux from the element 20 after coupling it by the corresponding lens 30; and it is constituted by filling the inside of the casing hermetically sealed by the lens 30 and the element 20 with transparent liquid 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a light source device and a method for assembling the light source device.

[0002]

2. Description of the Related Art One or more light source elements, one or more coupling lenses respectively corresponding to one or more light sources, and a casing for integrally holding the light sources and the coupling lens are provided. A light source device that couples a light beam with a corresponding coupling lens and emits the light beam is known in relation to an optical scanning device or the like.

In such a light source device, in order for the coupling lens to exhibit a desired coupling function such as a collimating function, the position of the coupling lens with respect to the light source element is precisely adjusted in the optical axis direction. There must be. Conventionally, in this position adjustment, when assembling the light source device, the position of the coupling lens is finely adjusted using a tool, and the light source element is turned on each time the adjustment is performed to check whether a desired coupling function is realized. The steps were repeated until the above-mentioned coupling function was realized. That is, when the coupling lens is displaced in the optical axis direction by the tool, the tool hinders the coupling function and cannot be examined. Therefore, the position adjustment of the coupling lens by the tool and the inspection of the coupling function are performed alternately. It is necessary. For this reason, the workability of assembling the light source device is poor, and there is a problem that it takes time to assemble even a skilled assembler.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to realize a novel light source device which is excellent in assemblability and which can be made more compact than a conventional light source device. Another object of the present invention is to realize a method for assembling a light source device that can easily assemble the light source device.

[0005]

According to the light source device of the present invention, one or more light source elements, one or more coupling lenses corresponding to the individual light source elements, and the light source elements and the coupling lens are integrally held. And a light source device that couples and emits a light beam from a light source element with a corresponding coupling lens ”, which is characterized by“ one or more coupling lenses and one or more coupling lenses ”. A transparent liquid is filled in the casing sealed with the light source element "(claim 1).

[0006] The "transparent liquid" enclosed in the casing is water or alcohol (ethyl alcohol or methyl alcohol or a mixture thereof).
Can be used (claim 2). It goes without saying that various organic and inorganic liquids can be used as the transparent liquid.

As described above, when a transparent liquid is interposed between the coupling lens and the light source element, the transparent liquid has a higher refractive index than air, so that the transparent liquid has a higher refractive index than the conventional light source device. The optical distance required between the light source element and the coupling lens can be mechanically shortened as compared with the case where air is between the coupling lens and the light source device, so that the light source device can be made compact. .

Further, since a liquid has a much larger heat capacity than air, when a "plastic lens whose optical characteristics change due to temperature fluctuations" is used as a coupling lens, the influence of temperature fluctuations on the coupling lens is reduced. It can be effectively reduced.

The "casing" may be constituted as an "integral unit" as a whole, but a "light source holder" for holding one or more light source elements and a "lens holder" for holding one or more coupling lenses. May be integrated by a fixing means such as adhesion (claim 3).

As the "one or more light source elements" used in the light source device, a light emitting diode (LD) can be used, but a "semiconductor laser" is preferable (claim 4).

The function of the coupling lens may be a function of changing the light beam from the light source element into a "weakly divergent light beam" or a "weakly convergent light beam" depending on the use of the light source device. (Claim 5).

Since one or more light source elements are used in the light source device, one or two or more light source elements may be used. In particular, when two light source elements are used (in this case, naturally, two coupling lenses are used). The light source device may have "combining prism means" for combining two light beams coupled by the two coupling lenses (claim 6), and such a light source device is a light source for a two-beam scanning device. It can be suitably used as an apparatus.

A method for assembling a light source device according to the present invention is a method for assembling the light source device according to any one of the first to fifth aspects (including a portion excluding the combining prism means of the light source device according to the sixth aspect). Therefore, it has the following features (claim 7).

The casing has a portion for holding one or more light source elements and is formed with a "coupling lens holding hole, a liquid inlet / outlet, a fixing hole, and a discharge hole". The “coupling lens holding hole” is a hole for holding the coupling lens corresponding to the light source element held in the casing so as to be displaceable in the optical axis direction. The “liquid inlet / outlet” is a hole through which a fluid flows in / out of the casing. The “fixing hole” is a hole for fixing the coupling lens positioned with respect to the coupling lens holding hole to the casing.

The "discharge hole" is a hole for discharging the air inside the casing to the outside of the casing.

One or more light source elements are held in a casing, and a “lens cell fixedly holding a coupling lens” is fitted in the coupling lens holding hole so as to be slidable in the optical axis direction of the coupling lens. I do. In this state, while introducing the liquid into the casing through the liquid inlet / outlet (by means such as a pump or an injector), the air inside the casing is discharged from the discharge hole to fill the inside of the casing with the introduced liquid, and then discharged. Close the hole.

Next, the amount of liquid in the casing is adjusted (by the pump or the like), and the coupling lens is displaced in the optical axis direction by the "difference between air pressure and liquid pressure" acting on the coupling lens in the optical axis direction. At least the position of the coupling lens in the optical axis direction is adjusted, and the adjusted coupling lens is fixed to the casing using the fixing hole. At this time, the light source element emits light, and the function of the coupling lens can be detected. That is, the position of the coupling lens can be adjusted while turning on the light source element and checking the coupling function of the coupling lens.

One or more coupling lenses are fixed to the casing as described above, and the liquid filling and closing holes are closed to seal the liquid filling the casing in the casing.

In the invention according to claim 7, the casing has a structure in which the fixing hole for fixing the coupling lens to the casing also serves as a discharge hole for discharging air inside the casing to the outside of the casing. It may be used (claim 8).

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view for explaining an embodiment in which the assembling method according to claim 7 is applied to "assembly of a single beam light source device". It is assumed that a parallel light beam is emitted from the light source device. Therefore, the coupling function of the coupling lens is a collimating function (claim 5).

In FIG. 1 (a), a light source holder 10 is a plate-shaped and fixedly holds a semiconductor laser 20 as a "light source element" in a light source element holding portion formed therethrough. ). The lens holder 12 is a holder for holding the coupling lens 30, and is integrated with the light source holder 10 as illustrated. Light source holder 1
The means for integrating the lens holder 12 with the lens holder 12 is "adhesion" in the illustrated example, but may be mechanical means such as screwing. The light source holder 10 and the lens holder 12 integrated with each other constitute a "casing" (claim 3).

The lens holder 12 has a liquid inlet / outlet 121 for allowing a fluid to flow into and out of the casing, a coupling lens holding hole 120, and a coupling lens 30 positioned with respect to the coupling lens holding hole 120. Hole 123 for discharging the air inside the casing to the outside of the casing.
22 are formed.

As shown in FIG. 1A, a coupling lens 3 is inserted into a coupling lens holding hole 120 in a casing holding a semiconductor laser 20 as a light source element.
The lens cell 32 fixedly holding 0 is fitted slidably in the direction of the optical axis AX of the coupling lens 30. This “fitting” is performed such that the outer peripheral surface of the lens cell 32 and the inner peripheral surface of the coupling lens holding hole 120 “smoothly rub” each other so that the sliding is performed in the “airtight state”. . In this state, the held optical axis AX of the coupling lens 30 matches the light emitting unit of the semiconductor laser 20.

When the lens cell 32 holding the coupling lens 30 is fitted into the coupling lens holding hole 120 as shown in FIG. 1A, the fixing hole 123 is closed by the outer peripheral surface of the lens cell 32. On the other hand, the light source holder 10
The hole of the light source element holding portion is closed by the semiconductor laser 20 in an airtight state. Of course, if necessary, appropriate sealing means can be used to ensure the airtight state of the hole of the light source element holding portion.

In the above state, as shown in FIG. 1 (a), a transparent liquid, for example, water or alcohol (Claim 2) is introduced into the inside of the casing through the liquid inlet / outlet 121 while the inside of the casing is being introduced. The air is discharged from the discharge holes 122 to fill the inside of the casing with the introduced liquid. The introduced liquid is allowed to slightly overflow from the discharge hole 122 so that the inside of the casing is completely filled. Also,
To introduce the liquid, a tube for injection (not shown) is connected to the liquid inlet / outlet 121 and a pump or the like (manual or automatic) may be used.
Is performed by injecting a liquid.

As shown in FIG. 1B, when the inside of the casing is filled with the introduced liquid 50, the discharge holes 122 are formed.
Means for closing (in the example shown, packing and locking screws) 6
Close by 1. In this state, the semiconductor laser 20 is turned on to emit a light beam from the coupling lens 30.

Next, by injecting or withdrawing a liquid into the casing to adjust the amount of liquid in the casing, the difference between the pressure acting on the optical axis of the coupling lens 30 in the optical axis direction and the liquid pressure causes the coupling. The lens cell 32 holding the lens 30 is displaced in the direction of the optical axis AX to adjust the position of the coupling lens in the direction of the optical axis so that the light beam coupled by the coupling lens 30 becomes a “desired parallel light beam”. To

In this state, the coupling lens 30 whose position has been adjusted is fixed to the casing by using the fixing hole 123, and then the liquid filling and closing hole 121 is closed, so that the liquid filling the casing is filled into the casing. Seal. In the illustrated example, an adhesive 62 is used as “fixing means” for fixing the coupling lens 30 to the casing by the fixing hole 123, and the lens cell 32 is adhesively fixed to the inner wall of the coupling lens holding hole 120. . In addition, the closing means 63 using packing and locking screws is used to close the liquid inlet / outlet 121.

The light source device thus obtained (FIG. 1 (c))
Are one light source element 20, one corresponding coupling lens 30, and casings 10, 1 for integrally holding the light source element 20 and the coupling lens 30.
A light beam from the light source element 20 is coupled (collimated) by the corresponding coupling lens 30 and emitted, and is provided inside a casing sealed by the coupling lens 30 and the light source element 20. It is filled with a transparent liquid 50 (claim 1).

The exhaust hole 122 in the lens holder 12 can be omitted as follows. That is, instead of providing the exhaust hole 122, the fixing hole 123 also serves as the exhaust hole. In this case, first, the lens cell 32 holding the coupling lens 30
Is fitted “shallowly” into the coupling lens holding hole 120 so that the lens cell 32 does not block the fixing hole 123. The air inside is exhausted from the fixing hole 123, and the inside of the casing is filled with the liquid 50. In this state, the lens cell 32 is connected to the coupling lens holding hole 12.
Then, the fixing hole 123 is closed with the outer peripheral surface of the lens cell 32.

Thereafter, by adjusting the amount of liquid in the casing by injecting or withdrawing the liquid into the casing, the difference between the pressure acting on the optical axis of the coupling lens 30 in the optical axis direction and the liquid pressure is applied. The position of the coupling lens in the optical axis direction is adjusted by displacing the lens cell 32 holding the ring lens 30 in the direction of the optical axis AX, and the position of the adjusted coupling lens 30 is fixed to the casing using the fixing hole 123. By fixing and then closing the liquid inlet / outlet 121, the liquid filling the casing may be sealed in the casing.

In the above, the assembling of the "single beam light source device" has been described, but the above description has been changed to "a light source device having two or more light source elements and two or more couplings".
The case is easy to extend.

FIG. 2 shows an embodiment of the light source device according to the sixth aspect. As shown in FIG.
0A and 10B are semiconductor lasers 2 as light source elements, respectively.
0A and 20B, and are integrated with the lens holder 12A. The light source holders 10A and 10B and the lens holder 12A constitute a "casing" and form "two independent spaces" inside the casing.

The lens holder 12A holds the semiconductor laser 20
Coupling lenses 30A, 30 corresponding to A, 20B
B (each fixedly held by the lens cells 32A and 32B), and has two coupling lens holding holes.
A, 30B are fitted.

A transparent liquid 50 is filled and sealed in two independent spaces inside the casing. The liquid is sealed “per space” in the manner described above. In FIG. 2, reference numerals 63A and 63B denote “packing and locking screws” which are closing means for closing the liquid inlet / outlet, and reference numerals 62A and 62B denote “lens cells using a fixing hole also serving as an exhaust port. 32A and 32B are integrated with the casing. "

In FIG. 2, a “composite prism” indicated by reference numeral 70 is held by a prism holder 90. The combining prism 70 has a reflection slope 71 and a polarization reflection / transmission film 72. In addition, the half-wave plate 80 is
It is affixed as shown in FIG.

The light beam emitted from the semiconductor laser 20A passes through the liquid 50, is collimated by the coupling lens 30A, passes through the polarization reflection / transmission film 72 of the combining prism 70, and exits from the combining prism 70. The light beam emitted from the semiconductor laser 20B passes through the liquid 50,
Collimated by the coupling lens 30B,
By passing through the two-wavelength plate 80, the polarization plane is turned by 90 degrees, is sequentially reflected by the reflection slope 71 and the polarization reflection / transmission film 72, and exits from the combining prism 70.

The light emitting portion of the semiconductor laser 20B is slightly shifted from the optical axis of the coupling lens 30B.
Therefore, the two parallel light beams emitted from the combining prism 70 form a slight angle with each other. Such a light source device is used as a light source device for a two-beam scanning device, and two emitted parallel light beams are imaged as two light spots separated from each other on a surface to be scanned by a common optical system.
Note that the two light beams emitted from the combining prism 70 are made into a “circularly polarized state” by a 波長 wavelength plate (not shown) in order to correct so-called shading. Synthetic prism 70
The half-wave plate 80 and the prism holder 90 constitute "composite prism means".

In order to assemble the light source device shown in FIG.
With the combining prism means removed, the position of the coupling lenses 30A and 30B is adjusted, and the liquid 50 is sealed in the casing. At this time, the light emitting section of the semiconductor laser 20B is positioned on the optical axis of the coupling lens 30B.

Next, after assembling the combining prism means, the amount of deviation between the light emitting portion of the semiconductor laser 20B and the optical axis of the coupling lens 30B is adjusted, and the minute angle between the two light beams emitted from the combining prism means is adjusted. I do.

[0041]

As described above, according to the present invention, a novel light source device and a method for assembling the same can be realized. According to the “assembly method” of the present invention, the coupling lens is continuously displaced in the optical axis direction by the inflow and outflow of the liquid into the casing in the lighting state of the light source element, and the coupling lens is examined while examining the coupling function. Since it is assembled, the coupling function can be easily adjusted and realized, and the light source device can be easily assembled.

Further, the light source device of the present invention is easy to assemble, and the space between the light source element and the coupling lens is filled with a transparent liquid, so that the light source device is more effective than the conventional one. In the case where a plastic lens is used as the coupling lens, the effect of temperature fluctuation can be effectively reduced.

[Brief description of the drawings]

FIG. 1 is a view for explaining an embodiment of an assembling method of a light source device according to the present invention.

FIG. 2 is a view for explaining one embodiment of a light source device according to claim 6;

[Explanation of symbols]

Reference Signs List 10 light source holder 12 lens holder (constituting casing with light source holder 10) 20 semiconductor laser (light source element) 30 coupling lens 50 liquid

Claims (8)

[Claims] 1. A light source device comprising: at least one light source element; at least one coupling lens corresponding to each light source element; and a casing integrally holding the light source element and the coupling lens. Wherein the light flux is coupled by a corresponding coupling lens and emitted, wherein a transparent liquid is filled in a casing sealed by the at least one coupling lens and the at least one light source element. Light source device. 2. The light source device according to claim 1, wherein the transparent liquid sealed in the casing is water or alcohol. 3. The light source device according to claim 1, wherein a light source holder holding one or more light source elements and a lens holder holding one or more coupling lenses are integrated to form a casing. A light source device characterized by the above-mentioned. 4. The light source device according to claim 1, wherein at least one of the light source elements is a semiconductor laser. 5. The light source device according to claim 1, wherein the coupling function of the coupling lens is a collimating function. 6. A light source device according to claim 1, further comprising two light source elements and two coupling lenses, wherein said light source device comprises two light beams. A light source device comprising: 7. A method for assembling the light source device according to claim 1, wherein the casing has a liquid inlet / outlet through which a fluid flows in and out of the casing, and a coupling lens holding hole in the casing. Holds one or more light source elements using a hole formed with a fixing hole for fixing the coupling lens positioned to the casing to the above-mentioned casing and a discharge hole for discharging air inside the casing to the outside of the casing. A lens cell fixedly holding the coupling lens is fitted slidably in the optical axis direction of the coupling lens in the coupling lens holding hole in the casing, and the liquid enters and exits the casing through the liquid inlet / outlet hole. While introducing, the air inside the casing is discharged from the discharge hole to fill the inside of the casing with the introduced liquid. The closed, then by adjusting the amount of liquid inside the casing,
The position of the coupling lens in the optical axis direction is adjusted by displacing the coupling lens in the optical axis direction by the difference between the atmospheric pressure and the hydraulic pressure acting on the coupling lens in the optical axis direction. A method of assembling a light source device, wherein a liquid filling a casing is sealed in a casing by fixing the casing to a casing by using a fixing hole and closing a liquid inlet / outlet. 8. The method for assembling a light source device according to claim 7, wherein the casing has a fixing hole for fixing the coupling lens to the casing, and a discharge hole for discharging air inside the casing to the outside of the casing. A method for assembling a light source device, characterized in that a light source device is used.