JPH0931633A - Optical thin film forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical thin film forming device capable of forming optical thin films having accurate optical characteristics by monitoring the forming state of the optical thin films. SOLUTION: A vacuum bell-jar 1 is internally provided with a shutter 13 which separates the upper part to a vacuum film forming chamber 11 for forming the optical thin films by vapor deposition on the end face of an optical fiber 2 and the lower part to an evaporating chamber 13 disposed with an evaporating device 12b, etc., for evaporating the thin film material in a crucible 12a and is controllable in opening and closing between the evaporating chamber and the vacuum film forming chamber and an optical fiber drawing-out port 11b in the prescribed place in the vacuum film forming chamber. The other end of the optical fiber is drawn out to the outside of the vacuum film forming chamber. The outside of the vacuum bell-jar is provided with a half prism 4 which introduces part of the light from a standard light source 3 into the other end of the optical fiber and reflects the rest by 90 deg., an optical sensor 5 which detects the intensity of the reflected light from this half prism and a control circuit 6 which controls the shutter by monitoring the detection signal from this optical sensor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical thin film forming apparatus, and more particularly to a device for monitoring a thin film forming state and controlling a shutter of a dissolving layer for dissolving a thin film material.

[0002]

2. Description of the Related Art Conventionally, there is no apparatus for forming a thin film such as an antireflection film or a dichroic filter on the end face of an optical fiber. For example, as shown in FIG. 2, a vacuum film forming chamber, an evaporation chamber, and the vacuum film forming unit. A vacuum bell jar is installed between the chamber and the evaporation chamber to control the opening and closing from the outside.To form an optical thin film such as an antireflection film or dichroic filter on the end face of the optical fiber by vacuum evaporation, the optical fiber is vacuum-formed. It is possible to deposit the thin film material on the end face of the optical fiber by putting it in a film chamber to make a vacuum, closing the shutter, putting the thin film material in a crucible provided in the evaporation chamber and heating it, and opening the shutter for a predetermined time. However, with this configuration, in order to set the forming conditions such as the thin film material, the melting temperature, and the vacuum state according to the predetermined optical characteristics, it is necessary to repeat the test in advance to determine the set value, which requires a lot of labor and time. In addition, the optical characteristics of the finished optical thin film required a lot of variations and could not be used.

[0003]

SUMMARY OF THE INVENTION The present invention solves the problems described above and forms an optical thin film while monitoring the formation state of the optical thin film, thereby forming an optical thin film having accurate optical characteristics. It is an object of the present invention to provide an optical thin film forming apparatus that can be used.

[0004]

In order to solve the above-mentioned problems, the present invention has a vacuum film forming chamber for forming an optical thin film by vapor deposition on the end face of an optical fiber inside a vacuum bell jar, and a lower part inside a crucible. A shutter which is separated into an evaporation chamber in which an evaporation device for evaporating a thin film material and the like is provided, and a shutter which can be opened and closed from the outside between the evaporation chamber and the vacuum film forming chamber and a predetermined place of the vacuum film forming chamber An optical fiber outlet is provided to draw the other end of the optical fiber to the outside of the vacuum film forming chamber, and a standard light source such as a laser beam and a part of the light from the standard light source are passed to the outside of the vacuum bell jar to the other end of the optical fiber. And a light sensor such as a photomultiplier (PM) that detects the intensity of the reflected light from the half prism and a detection signal from the light sensor. It provided a control circuit for controlling the shutter monitor.

[0005]

According to the optical thin film forming apparatus of the present invention configured as described above, the light from the standard light source is guided to the other end of the optical fiber drawn out of the vacuum film forming chamber through the half prism, and the optical fiber The light reflected from one end is reflected by the half prism, the intensity of the reflected light is detected by an optical sensor such as a photomultiplier (PM), and the detection signal is compared with a reference value, whereby the evaporation chamber and the vacuum chamber are vacuumed. The opening or closing of the shutter provided between the film formation chambers is controlled.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical thin film forming apparatus according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a system block diagram showing an embodiment of an optical thin film forming apparatus according to the present invention. In the figure, reference numeral 1 is a vacuum bell jar, and a vacuum pump 11
a, a vacuum film forming chamber 11 having an optical fiber outlet 11b, a crucible 12a for containing a thin film material, and an evaporation chamber 12 having a resistance heating device 12b for heating and evaporating the thin film material in the crucible 12; Chamber 12 and the vacuum film forming chamber 1
1 and a shutter 13 whose opening and closing can be controlled. In the present embodiment, the resistance heating type resistance heating device 12b is used as the evaporation device, but an electron beam type evaporation device that evaporates by applying an electron beam to the thin film material or a sputtering method that evaporates the thin film material by arc discharge is used. It goes without saying that an evaporator can be used. Reference numeral 2 is an optical fiber for forming an optical thin film such as an antireflection film or a dichroic filter on the end face. Reference numeral 3 denotes a standard light source, which emits laser light having a known light intensity.
Reference numeral 4 denotes a half mirror, which passes a part of light incident at an incident angle of 90 degrees and reflects a part of the light by 90 degrees. An optical sensor 5 detects the intensity of light such as photomultiplier (PM). Reference numeral 6 denotes a control circuit, which is a reference value storage unit 6 described later.
1, a comparison unit 62, a determination unit 63, a shutter drive unit 64, and a transportation control unit 65. Reference numeral 7 denotes a transportation section, which is moved by the control of the transportation control section 65 to move the crucible 12a provided in the vacuum bell jar 1 and replace it with a crucible 12a provided in a preheating chamber 8 described later. Reference numeral 8 denotes the preheating chamber in which a plurality of crucibles 12a containing various thin film materials are housed and heated to a predetermined temperature by a resistance heating device 8b.

Reference numeral 61 is the reference value storage unit, which is a nonvolatile RA.
M61a, data writing unit 61b, data input unit 61
and the reference value data input from the data input unit 61c in the data writing unit 61b.
It is stored in 1a. Reference numeral 62 denotes the comparison unit, which compares the detection signal from the optical sensor 5 with the reference value data stored in the reference value storage unit 61 and outputs a comparison signal. 6
Reference numeral 3 denotes the discriminating unit that discriminates whether the shutter is opened or closed based on the comparison signal from the comparison unit, and outputs an opening / closing control signal. A shutter drive unit 64 drives the shutter 13 in response to an opening / closing control signal from the determination unit 63. A transportation control unit 65 controls the transportation unit 7 based on an opening / closing control signal from the determination unit 63 and a drive signal from the shutter driving unit 64. 6
A reference value control unit 6 includes a control unit 66a, a procedure program storage unit 66b, and a procedure program input unit 66c. The reference value changing procedure program is input from the procedure program input unit 66c, and the procedure program is changed to the procedure program. The procedure program storage unit 66 is written in the storage unit 66b.
The control unit 66a reads the reference data stored in the reference value storage unit in accordance with the procedure stored in b.
In this embodiment, the determination result of the determination unit 63 is controlled to open or close the shutter 64. However, when an electron beam type or sputtering type evaporation device is used, the evaporation control unit 67 is provided. The evaporation device may be controlled based on the determination result of the determination unit 63 to control the evaporation amount of the thin film material.

Next, the operation of the above configuration will be described. First, inside the vacuum bell jar 1, the other end of the optical fiber 2 for forming an optical thin film such as an antireflection film and a dichroic filter on the end face is pulled out to the outside from an optical fiber outlet 11b provided in the vacuum film forming chamber 11, and a vacuum pump The vacuum film forming chamber 11 is evacuated by operating 11a. Further, the crucible 12a containing the thin film material is heated by operating the resistance heating device 12b to melt the thin film material at a predetermined temperature. When the temperature of the crucible 12a reaches a predetermined temperature, the shutter 13 is opened to evaporate the thin film material in the vacuum film forming chamber 11 and deposit it on the end face of the optical fiber 2 to form an optical thin film.

On the other hand, outside the vacuum bell jar 1, the standard laser light from the standard light source 3 is guided through the half mirror 4 to the other end of the optical fiber 2 drawn from the optical fiber drawing port 11b, and reflected from the optical fiber 2. The light is reflected by the half mirror 4, and the light sensor 5
The intensity of this reflected light is detected by, and this detection data (Ds)
Is input to the control unit 6. For example, when an antireflection film is formed of a multi-layered thin film on the end face so that the reflected light of the optical fiber 2 has a predetermined specification, it corresponds to each film forming process based on the specification of the reflected light in the reference value storage unit 61 in advance. By storing a plurality of reference value data (Dstdn)
The reference value control unit 66 reads predetermined reference value data (Dstk) from the reference value data (Dstdn) according to the procedure of the procedure program stored in the procedure program storage unit 66b, and the reference value data (Dstk) and each film formation. The detection data (Ds) input to the control unit 6 for each process is compared by the comparison unit 62, and the detection data (Ds) is the reference value data (D
When it becomes stk) or less, the determination unit 63 outputs a shutter closing signal to close the shutter 13 via the shutter driving unit 64.

The shutter closing signal from the discriminating unit 63 is input to the transportation control unit 65, and after a lapse of a predetermined time, the transportation unit is controlled to be placed in the vacuum bell jar 1 and the crucible 12a.
Is moved to replace a predetermined crucible 12a arranged in the preheating chamber 8 and the process proceeds to the next film forming step. When the one film forming step is completed, the reference value control unit 66 reads out the next reference value data stored in the reference value storage unit 6 according to the procedure of the procedure program stored in the procedure program storage unit 66b.

Above, the carrying section 7 is provided and the crucible 1 is automatically operated.
Although the example in which 2a is exchanged is shown, the transportation part 7 is not provided, the shutter 13 is closed, and after the completion of one film forming process, the crucible 12a manually arranged in the vacuum bell jar 1 is moved to the preheating chamber 8. However, it may be replaced with a predetermined crucible 12a arranged in the preheating chamber 8 to shift to the next film forming step. In the embodiment, the thin film is formed on the end face of one optical fiber. However, when the thin film is formed on the end face of a plurality of optical fiber bundles, one or several of the bundles are sampled and fed back. It is feasible.

[0012]

As described above, according to the optical thin film forming apparatus of the present invention, the light from the standard light source is guided through the half prism to the other end of the optical fiber drawn out of the vacuum film forming chamber, and the optical fiber The light reflected from one end is reflected by the half prism, the intensity of the reflected light is detected by an optical sensor such as a photomultiplier (PM), and the detection signal is compared with a reference value, whereby the evaporation chamber and the vacuum chamber are vacuumed. Since the opening or closing of the shutter provided between the film forming chambers is controlled, the optical thin film is formed while monitoring the formation state of the optical thin film, thereby forming the optical thin film having accurate optical characteristics. It is possible to provide an optical thin film forming apparatus capable of performing the above.

[Brief description of drawings]

FIG. 1 is a system block diagram showing an embodiment of an optical thin film forming apparatus according to the present invention.

FIG. 2 shows a conventional optical thin film forming method using a vacuum bell jar.

[Explanation of symbols]

 1 vacuum bell jar 2 optical fiber 3 standard light source 4 half mirror 5 optical sensor 6 control unit 7 transport unit 8 preheating chamber 11 vacuum film forming chamber 11a vacuum pump 11b outlet 12 evaporation chamber 12a crucible 12b resistance heating device (evaporation device) 13 shutter 61 Reference data storage unit 61a Nonvolatile RAM 61b Writing unit 61c Data input unit 62 Comparison unit 63 Discrimination unit 64 Drive unit 65 Transport control unit 66 Reference value control unit 66a Control unit 66b Procedure program storage unit 66c Procedure program input unit 67 (Evaporation control Part)

Claims (10)

[Claims] 1. A vacuum film forming chamber for forming an optical thin film by vapor deposition on an end face of an optical fiber in an upper part inside the vacuum bell jar,
The lower part is separated into an evaporation chamber in which an evaporation device or the like for evaporating the thin film material in the crucible is provided, and a shutter which can be opened / closed between the evaporation chamber and the vacuum film formation chamber from the outside, and the vacuum film formation chamber The other end of the optical fiber is pulled out to the outside of the vacuum film forming chamber by providing an optical fiber outlet at a predetermined location of the vacuum bell jar, and a standard light source such as laser light and a part of the light from the standard light source are passed outside the vacuum bell jar. A half prism which is introduced into the other end of the optical fiber and reflects the remaining part by 90 degrees,
An optical sensor such as a photomultiplier (PM) that detects the intensity of the reflected light from the half prism, and a control circuit that monitors the detection signal from the optical sensor and controls the shutter are provided. Optical thin film forming apparatus. 2. The optical thin film forming apparatus according to claim 1, wherein the evaporation device provided in the evaporation chamber comprises a resistance heating type heating device. 3. The optical thin film forming apparatus according to claim 1, wherein the evaporation device provided in the evaporation chamber includes an electron beam heating device. 4. The optical thin film forming apparatus according to claim 1, wherein the evaporation device provided in the evaporation chamber comprises a sputtering type discharge device. 5. The control circuit comprises a reference value storage section for storing a reference value, a comparator for comparing the reference value from the reference value storage section with a detection signal from the optical sensor, and 2. A comparison unit, which includes a determination unit that determines whether the shutter is open or closed, and a shutter drive unit that drives the shutter based on the determination result.
The optical thin film forming apparatus as described in the above. 6. The control circuit comprises a reference value storage section for storing a reference value, a comparator for comparing the reference value from the reference value storage section and a detection signal from the optical sensor, and As a result of the comparison, a determination unit that determines whether the shutter is open or closed, a shutter drive unit that drives the shutter based on the determination result, and the evaporation device is controlled based on the determination result to change the evaporation amount. The optical thin film forming apparatus according to claim 1, comprising an evaporation control unit. 7. A crucible provided in the evaporation chamber is detachably arranged, a carrier for moving the crucible is provided, and a crucible containing one or more thin film materials is provided in a preheating chamber arranged near the vacuum bell jar. The optical thin film forming apparatus according to claim 1, wherein the transporting machine is configured to exchange a predetermined crucible provided in a preheating chamber and a crucible provided in a vacuum bell jar. 8. The reference value storage unit is composed of a writable nonvolatile RAM, is provided with a data writing unit and a data input unit, and the data writing unit stores the reference value data input from the data input unit. The optical thin film forming apparatus according to claim 5 or 6, wherein the optical thin film forming apparatus is configured to be written in a portion. 9. The reference value storage unit stores one or more data, a reference value control unit, a procedure program storage unit,
A procedure program input unit is provided, a reference value changing procedure program is input from the procedure program input unit, the procedure program is written into the procedure program storage unit, and the reference value control unit follows the procedure of storing in the procedure program storage unit. The optical thin film forming apparatus according to claim 5 or 6, wherein the reference data stored in the storage unit is read out. 10. The control circuit comprises a reference value storage section for storing a reference value, a comparator for comparing the reference value from the reference value storage section with a detection signal from the optical sensor, and As a result of the comparison, a determination unit that determines whether the shutter is opened or closed, a shutter drive unit that drives the shutter based on the determination result, and a predetermined crucible and a preheating chamber that are provided in the vacuum bell jar after the shutter is closed. The optical thin film forming apparatus according to claim 7, further comprising: a transportation control unit that controls the transportation machine so as to replace it with a crucible.