JP5288442B2 - Shock-resistant optical seeker and its manufacturing method - Google Patents

Description

  The present invention relates to an impact-resistant optical seeker applicable to a target tracking guidance device and a method for manufacturing the same.

The target tracking guidance device irradiates a laser beam toward the target, causes the flying object to fly toward the target, and detects the laser reflected light of the laser beam reflected by the target by an optical seeker mounted on the flying object. The device captures the target and corrects the flight path of the flying object to guide the flying object toward the target.
In addition, an optical filter is used for the optical seeker of the target tracking guidance device in order to selectively reflect or transmit light of a specific wavelength (for example, a laser beam).

  Patent Documents 1 to 4 have already been disclosed as prior arts related to the target tracking guidance device and the optical filter.

The “target tracking guidance system and target tracking guidance method” of Patent Document 1 aims to make it possible to reliably guide a flying object toward a target while simplifying the equipment.
Therefore, in this invention, as shown in FIG. 6, in the flying object 50, the backscattered light of the laser beam LB irradiated from the infrared laser irradiation device 52 toward the target T is detected by the infrared sensor, and the system control unit The trajectory and direction of the laser beam LB are obtained from the detection result by the infrared sensor, and the trajectory and direction of the laser beam LB are compared with the flight position / velocity information of the flying object 50 detected by the position / velocity sensor. By determining the flight position and flight direction of the flying object 50 with respect to the laser beam LB, and generating a guidance signal corresponding to the deviation between the locus and direction of the laser beam LB and the flight position and flight direction, The flying object 50 is brought close to the laser beam LB so that the flying direction and the laser beam direction are substantially coincided with each other.

As shown in FIG. 7, the dielectric multilayer filter 61 of Patent Document 2 uses a substrate 69 made of a fluorinated polyimide thin film having a refractive index smaller than that of the multilayer film portion, and a dielectric by ion-assisted vapor deposition on the substrate 69. A multilayer film 60 is formed.
The fluorinated polyimide thin film has heat resistance and transparency, can be easily peeled off from the temporary substrate, and can produce a thin dielectric multilayer filter.

Patent Document 3 aims at a multifunctional optical filter having excellent manufacturability and high mechanical strength.
This optical filter includes a visible filter layer having an absorption maximum with a transmittance of 0.01 to 80% in a wavelength range of 565 to 605 nm, a conductive layer having an electromagnetic wave blocking effect, and an infrared blocking layer on at least one side of a plastic transparent support. It has a hard coat layer and a heat conductive layer having a thermal conductivity of 0.4 W / m · K or more, and is directly attached to the viewing side of the image display device.

Patent Document 4 aims at an optical film having high impact resistance formed on a plastic substrate.
The method includes a step of laminating and forming a release layer and an optical filter on a first substrate, a step of peeling the optical filter from the first substrate, and a step of bonding the optical filter to the second substrate. Have Since the optical film manufactured by this method has flexibility, it can be provided in a portion having a curved surface or a display device. Further, since the optical film is not subjected to high temperature treatment, an optical film with high yield and high reliability can be formed.

JP 2002-90093 A, “Target Tracking Guidance System and Target Tracking Guidance Method” Japanese Patent Laid-Open No. 4-211203, “Dielectric multilayer filter, method for producing the same, and optical element using the same” Japanese Patent Laid-Open No. 2001-281442, “Optical Filter, Front Plate Using the Same, and Image Display Device” JP 2005-157324 A, “Method for producing optical film”

The optical filter used in the optical seeker described above is conventionally manufactured by forming a thin film multilayer film of a dielectric material matched to a desired wavelength by means such as vacuum deposition on the surface (one side / both sides) of a base material. Yes.
In general, as the number of thin film multilayer films increases, the degree of freedom in selecting light reflection / transmission improves. However, increasing the number of layers, on the other hand, increases the time during which the base material is exposed to heat during the manufacturing process, so the thermal characteristics (heat resistance characteristics) of the base material are important.

On the other hand, the optical filter requires a narrow-band bandpass filter in order to increase the signal-to-noise ratio (S / N ratio) of the signal detected by the optical seeker.
In order to obtain such a narrow-band bandpass filter, the number of thin-film multilayer films needs to be at least 40 layers, preferably 60 layers or more.
Therefore, conventionally, such an optical filter has been manufactured using a heat-resistant glass having a heat-resistant temperature exceeding 350 ° C. as a base material.

  However, the target tracking guidance device is normally fired and receives a high impact exceeding 10,000 G at the time of launch. For this reason, in the conventional optical filter, the base material (glass) is a brittle material, and there is a risk of damage such as cracking and cracking due to high impact at the time of launch.

  The present invention has been developed to solve the above-described problems. That is, the object of the present invention is to detect light (for example, a laser beam) to be used with a high S / N ratio, and to prevent damage such as cracks and cracks even when subjected to high impact exceeding 10,000 G. It is an object of the present invention to provide an impact-resistant optical seeker that is not subjected to such damage and a method for manufacturing the same.

According to the present invention, an impact-resistant optical seeker that receives a high impact at the time of launch and detects light of a predetermined narrow band,
An optical sensor for detecting the light;
A condenser lens and an optical filter disposed in front of the optical sensor;
An optical dome disposed in front of the condenser lens and the optical filter to protect them,
The condensing lens, the optical filter, and the optical dome are made of an impact-resistant heat-resistant plastic that can withstand the high impact, has a high light transmittance, and has a transition temperature of about 200 ° C. or more.
A part or all of the condensing lens, the optical filter, and the optical dome has a thin film multilayer film on one or both surfaces thereof, and the entire thin film multilayer film constitutes a predetermined narrow band pass filter. An impact resistant optical seeker is provided.

  According to a preferred embodiment of the present invention, the impact-resistant heat-resistant plastic is polyetherimide, polyphenylsulfone or polyfersulfone.

Further, according to the present invention, there is provided a method for manufacturing an impact-resistant optical seeker that receives a high impact at the time of launch and detects light of a predetermined narrow band,
A condensing lens and an optical filter disposed on the front surface of the optical sensor for detecting the light, and an optical dome disposed on the front surface for protecting the condensing lens, withstands the high impact, has a high light transmittance, and Manufactured with impact and heat resistant plastics with a transition temperature of about 200 ° C or higher,
Furthermore, a thin film multilayer film is formed on one or both surfaces of the condensing lens, the optical filter, and the optical dome, and the entire thin film multilayer film constitutes a predetermined narrow-band bandpass filter. A method for producing an impact-resistant optical seeker is provided.

  According to a preferred embodiment of the present invention, the impact-resistant heat-resistant plastic is polyetherimide, polyphenylsulfone or polyfersulfone.

  The thin film multilayer film is formed at a temperature equal to or lower than the transition temperature of the impact-resistant heat-resistant plastic while taking a cooling period in the middle by vacuum vapor deposition, ion-assisted vapor deposition, or sputtering.

  According to the apparatus and method of the present invention, some or all of the condenser lens, the optical filter, and the optical dome have the thin film multilayer film on one or both surfaces thereof, and the entire thin film multilayer film has a predetermined narrow band. Therefore, light corresponding to this narrow band (for example, a laser beam) can be detected with a high S / N ratio.

  In addition, the condensing lens, optical filter and optical dome are made of impact-resistant and heat-resistant plastic that can withstand high impact at the time of launch, so even if subjected to high impact exceeding 10,000 G, cracks, cracks, etc. Almost no damage.

  Therefore, by using a plastic base material that originally has impact resistance, it is possible to solve the fragility of conventional glass materials with respect to impact.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is an explanatory diagram of interference in a single-layer thin film.
In FIG. 1A, 1 is a substrate (glass or plastic), 2 is a single-layer thin film formed on the substrate surface (refractive index is n), and 3 is light of wavelength λ (for example, a laser beam). .

Of the light 3 of A and B, the light reflected on the surface of the single layer thin film 2 is A ′, B ′, refracted on the surface O of the single layer thin film 2 and totally reflected on the surface of the substrate 1. Let C be the light that is refracted by the surface Q of 2 and returns to the air side. Refraction at the surfaces O and Q follows Snell's law.
By setting the thickness (optical film thickness: nd) of the single layer thin film 2 to ¼ of the wavelength λ or a thickness close thereto, the light B ′ and the light C can be made to interfere with each other.
For example, as shown in FIG. 1B, when the light B ′ (B-1) and the light C (B-2) are synchronized at the same timing, the amplitude of the light 3 ( That is, the strength) can be increased.
Conversely, as shown in FIG. 1C, when the light B ′ (B-1) and the light C (B-2) are synchronized at a timing shifted by π / 2, as shown in (B-3). In addition, the amplitude (ie, intensity) of the light 3 can be reduced.

  Similarly, in the interference phenomenon of a multilayer film, when two types of transparent films having different refractive indexes (optical film thickness = 1/4 of wavelength λ) are alternately laminated on the substrate, the light is strengthened or canceled by the interference action. High reflection and low reflection are generated.

FIG. 2 is a diagram showing the spectral characteristics of the thin film multilayer film. In this figure, the horizontal axis is the wavelength [nm], the vertical axis is the loss [dB], and the three curves in the figure show the case where the thin film multilayer film is 20, 40, 60 layers.
As can be seen from this figure, it is generally known that the spectral characteristics become steep when the number of thin-film multilayer films is increased.
In addition, as described above, in order to increase the signal-to-noise ratio (S / N ratio) of the signal detected by the optical seeker, a narrow-band bandpass filter is necessary, and such a narrow-band bandpass filter is obtained. For this purpose, the number of layers of the thin film multilayer film is required to be at least 40 layers, preferably 60 layers.

  FIG. 3 is a view showing a first embodiment of the impact-resistant optical seeker of the present invention. The impact-resistant optical seeker 10 of the present invention receives a high impact (for example, 10,000 G) at the time of launch and detects a predetermined narrow-band light 3. The predetermined narrowband light 3 is narrowband light including the wavelength of the laser beam, for example.

In this figure, the impact-resistant optical seeker 10 of the present invention includes an optical sensor 12, a condenser lens 14, an optical filter 16, and an optical dome 18 in this order.
The optical sensor 12 is a CCD or a photodiode, and detects the intensity and direction of the predetermined narrowband light 3 (for example, a laser beam).
The condenser lens 14 and the optical filter 16 are disposed on the front surface of the optical sensor 12. The condensing lens 14 and the optical filter 16 may be in the reverse order of this figure.
In this example, the condensing lens 14 includes two convex lenses 14 a and condenses the light 3 incident from the outside onto the optical sensor 12. In addition, this invention is not limited to this structure, You may comprise with three or more lenses (convex lens or concave lens).
The optical dome 18 is disposed in front of the condenser lens 14 and the optical filter 16 and has a function of protecting them from external dust and wind and rain.

  The condensing lens 14, the optical filter 16, and the optical dome 18 described above can withstand a high impact (for example, 10,000 G) at the time of launch, have high transmittance of the light 3 in the narrow band, and have a transition temperature of about 200 ° C. Made of shock resistant heat resistant plastic. This impact-resistant heat-resistant plastic is, for example, polyetherimide, polyphenylsulfone, or polyfersulfone.

Further, a part or all of the condenser lens 14, the optical filter 16, and the optical dome 18 have a thin film multilayer film 20 on one or both surfaces thereof, and a predetermined narrow-band bandpass filter is formed on the entire thin film multilayer film 20. Configure.
In this example, the thin film multilayer 20 is provided on both surfaces of the two convex lenses 14 a, the front surface of the optical filter 16, and the back surface of the optical dome 18. The thin film multilayer films 20 on both surfaces of the convex lens 14a, the front surface of the optical filter 16, and the back surface of the optical dome 18 each have an arbitrary number of layers. Set the range.
For example, even when the thin film multilayer film 20 on the front surface of the optical filter 16 has 10 to 20 layers so as not to adversely affect, and the other thin film multilayer film 20 has 10 layers, the total thickness is 60 to 70 layers, which is a predetermined narrow width. A bandpass filter for the band can be configured.

FIG. 4 is a view showing a second embodiment of the impact-resistant optical seeker of the present invention.
In this figure, the impact-resistant optical seeker 10 of the present invention includes an optical sensor 12, a condenser lens 14, an optical filter 16, and an optical dome 18 in this order. The condensing lens 14 and the optical filter 16 may be in the reverse order of this figure.

In this example, the optical filter 16 includes three thin filters 16a.
In this example, the thin multilayer film 20 is provided on both surfaces of the three thin filters 16a. Each thin film multilayer film 20 of the three thin filters 16a has an arbitrary number of layers, and is set in a range in which each base material is exposed to heat during the manufacturing process and does not adversely affect.
For example, even when the thin film multilayer film 20 on both sides of the thin filter 16a is made 10 to 15 layers so as not to adversely affect, the total number of layers is 60 to 90, and a predetermined narrow band pass filter can be configured. .
Other configurations are the same as those of the first embodiment.

FIG. 5 is an explanatory diagram of the transmittance in the impact-resistant optical seeker of the present invention. In this figure, (A) is a relationship diagram between the wavelength and transmittance of one thin film multilayer film 20, and (B) is a relationship diagram between the wavelength and transmittance of another thin film multilayer film 20. When these two thin film multilayer films 20 are used in an optically overlapping manner, the relationship between the wavelength and the transmittance is the result of integrating (A) and (B) as shown in (C), resulting in a narrow band. Is done.
Accordingly, as described above, a part or all of the condenser lens 14, the optical filter 16, and the optical dome 18 are provided with a total of 60 layers or more of the thin film multilayer film 20 on one side or both sides thereof. As shown, a predetermined narrowband bandpass filter can be constructed.

Next, a method for manufacturing the above-described impact-resistant optical seeker 10 will be described.
The method of the present invention is a method of manufacturing an impact-resistant optical seeker 10 that receives a high impact (for example, 10,000 G) upon launch and detects a predetermined narrow band of light 3.

In the manufacturing method of the present invention, first, the condensing lens 14, the optical filter 16, and the optical dome 18 are resistant to high impact at the time of launch, have high light 3 transmittance, and have an impact resistance of about 200 ° C. or higher. Manufactured from heat-resistant plastic. This impact-resistant heat-resistant plastic is, for example, polyetherimide, polyphenylsulfone or polyfersulfone.
Next, in the first embodiment of the manufacturing method of the present invention, the thin film multilayer film 20 is formed on one or both surfaces of the condensing lens 14, the optical filter 16, and the optical dome 18, and the thin film multilayer film 20 is formed. As a whole, a predetermined narrow-band bandpass filter is formed.
The thin film multilayer film 20 is formed at a temperature equal to or lower than the transition temperature of the impact-resistant heat-resistant plastic while taking a cooling period in the middle by vacuum deposition, ion-assisted deposition, or sputtering.

  According to this method, the thin film multilayer film 20 can be dispersed and arranged in a plurality of optical elements, and the number of layers of the thin film multilayer film 20 of each optical element can be reduced to a range that is not affected by heat.

In the second embodiment of the manufacturing method of the present invention, first, a heat-resistant temporary base material having the same shape as one or both surfaces of a part or all of the condenser lens 14, the optical filter 16, and the optical dome 18 is prepared.
Next, a release layer is formed on the surface of the heat-resistant temporary base material, and then a thin film multilayer film 20 is formed on the surface of the release layer by vacuum deposition, ion-assisted deposition, or sputtering.
Next, the release layer is removed, the thin film multilayer film 20 is separated from the heat-resistant temporary base material, and is attached to one or both surfaces of the condensing lens 14, the optical filter 16, and the optical dome 18.
Other methods are the same as those in the first embodiment.

  According to this method, a material having high heat resistance (heat-resistant glass, ceramics, metal, etc.) can be used as the heat-resistant temporary base material, and the multi-layered thin film multilayer film 20 can be freely manufactured without considering thermal effects. can do.

  According to the apparatus and method of the present invention described above, a part or all of the condenser lens 14, the optical filter 16, and the optical dome 18 have the thin film multilayer film 20 on one surface or both surfaces thereof, and the entire thin film multilayer film 20. Since a band-pass filter having a predetermined narrow band is configured, light (for example, a laser beam) corresponding to the narrow band can be detected with a high S / N ratio.

  In addition, the condenser lens 12, the optical filter 16, and the optical dome 18 are made of a shock-resistant and heat-resistant plastic that can withstand a high impact at the time of launch. Little damage such as cracks.

  Therefore, by using a plastic base material that originally has impact resistance, it is possible to solve the fragility of conventional glass materials with respect to impact.

  It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist of the present invention.

It is interference explanatory drawing in a single layer thin film. It is a figure which shows the spectral characteristics of a thin film multilayer. It is a figure which shows 1st Embodiment of the impact-resistant optical seeker of this invention. It is a figure which shows 2nd Embodiment of the impact-resistant optical seeker of this invention. It is explanatory drawing of the transmittance | permeability in the impact-resistant optical seeker of this invention. 1 is a schematic diagram of a system disclosed in Patent Document 1. FIG. 6 is a schematic diagram of a dielectric multilayer filter of Patent Document 2. FIG.

Explanation of symbols

1 substrate (glass or plastic), 2 single layer thin film, 3 wavelength light,
10 shockproof optical seeker, 12 optical sensor,
14 condenser lens, 16 optical filter,
18 Optical Dome

Claims (5)

It is an impact-resistant optical seeker that receives a high impact at the time of launch and detects light of a predetermined narrow band,
An optical sensor for detecting the light;
A condenser lens and an optical filter disposed in front of the optical sensor;
An optical dome disposed in front of the condenser lens and the optical filter to protect them,
The condensing lens, the optical filter, and the optical dome are made of an impact-resistant heat-resistant plastic that can withstand the high impact, has a high light transmittance, and has a transition temperature of about 200 ° C. or more.
A part or all of the condensing lens, the optical filter, and the optical dome has a thin film multilayer film on one or both surfaces thereof, and the entire thin film multilayer film constitutes a predetermined narrow band pass filter. Characteristic impact-resistant optical seeker.   The impact-resistant optical seeker according to claim 1, wherein the impact-resistant heat-resistant plastic is polyetherimide, polyphenylsulfone, or polyfersulfone. A method of manufacturing an impact-resistant optical seeker that receives a high impact during launch and detects light of a predetermined narrow band,
A condensing lens and an optical filter disposed on the front surface of the optical sensor for detecting the light, and an optical dome disposed on the front surface for protecting the condensing lens, withstands the high impact, has a high light transmittance, and Manufactured with impact and heat resistant plastics with a transition temperature of about 200 ° C or higher,
Furthermore, a thin film multilayer film is formed on one or both surfaces of the condensing lens, the optical filter, and the optical dome, and the entire thin film multilayer film constitutes a predetermined narrow-band bandpass filter. A method for producing an impact-resistant optical seeker characterized by   4. The method for producing an impact-resistant optical seeker according to claim 3, wherein the impact-resistant heat-resistant plastic is polyetherimide, polyphenylsulfone, or polyfersulfone.   4. The thin film multilayer film according to claim 3, wherein the thin film multilayer film is formed at a temperature equal to or lower than a transition temperature of the impact and heat resistant plastic while taking a cooling period in between by vacuum deposition, ion assisted deposition, or sputtering. Manufacturing method of impact optical seeker.

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