JP4712147B2 - Laser irradiation method, method for producing an article with the skin removed - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for automatically peeling a skin covered with an epidermis, such as potatoes and apples. Alternatively, the present invention relates to a method and apparatus for removing dirt on a surface with dirt attached.
[0002]
[Prior art]
History tells us that attempts to automate the process of skinning food have long been made. Devices and methods for automatically peeling potato skins are widely used, and this has led to the automation of the food industry, such as sales of bento boxes, canned foods, and confectionery. Examples of confectionery that uses an automatic peeler include snacks typified by potato chips. Examples of canned foods that use an automatic peeler include peaches, grapes, and mandarin oranges. Typical methods for peeling these skins are listed below.
[0003]
First, take the case of peeling potato skin as an example.
There is a method in which potatoes are brought into contact with each other and the skin is scraped off by friction. Put a large amount of potatoes in a rotating container and make the potatoes touch each other. By rotating the rotating container at an appropriate speed, the potatoes rub against each other. This causes the skin to wear and consequently the skin is removed from the potato. At this time, the side surface of the rotating container may be covered with fine protrusions so that the skin can be peeled off more efficiently.
[0004]
Alternatively, there is a method of peeling using a peeler called a steam peeler. In this method, a large amount of potatoes is put in a steam peeler, high pressure steam is bathed on the surface of the potatoes, and when the skin becomes soft, the skin is washed and removed with a high pressure spray. Alternatively, there is a method of scraping the potato surface by friction with a peeler called a file peeler.
[0005]
Next, the example which peels a mandarin orange is given.
There are two types of citrus peels: an outer hard skin and an inner translucent skin. Here, we will describe how to peel the inner mandarin peel. The peel of mandarin orange is very light, and the body part inside the peel is very soft, so it is difficult to scrape it off like a potato. Therefore, in this case, a method of removing the skin by immersing the mandarin in a chemical solution that dissolves only the mandarin skin is adopted. In general, sodium hydroxide is used in the chemical solution.
[0006]
[Problems to be solved by the invention]
For example, if you try to remove the skin by rubbing each other like potatoes, you will shave even the body part under the skin. The part between the skin and the body is known for its high nutritional value, and it is not preferable that this part be discarded as industrial waste.
[0007]
Also, industrial waste such as potato skin is difficult to divert, and it is better to reduce the amount as much as possible. Potato skin is hard to rot and is not suitable for reuse as fertilizer. In many cases, it is also unsuitable as animal food.
[0008]
In the method of peeling using the steam peeler introduced above, the surface of the potato peeled using the steam peeler is heated, so that the quality change cannot be avoided. In addition, this method has a drawback that the volume of the potato after peeling is reduced more than necessary. The present invention provides an apparatus and method that efficiently removes only the extreme surface of the skin.
[0009]
[Means for Solving the Problems]
The present applicant devised a method for removing the skin by ablating the surface of the food material by efficiently irradiating the skin of the food material with intense light.
[0010]
For example, consider peeling a potato skin using a YAG laser (wavelength 1.06 μm). Potatoes have a high moisture layer just below their skin. When a YAG laser is irradiated toward a potato with a skin, the laser energy is instantaneously absorbed up to the area containing much moisture. In order to absorb more energy in the region, the potato may be previously moistened with moisture.
[0011]
At this time, when the potato is irradiated with a laser beam at an appropriate energy density, only the potato skin is ablated, and the skin is removed from the potato. The removed skin is completely separated from the potato body, for example, by blowing air. In the present specification, a device that blows air onto an object to be irradiated is referred to as an air injection device. Alternatively, both may be completely separated by washing with water. In the present specification, a device for applying water to an irradiated object is referred to as a water jet device. When the potato is washed with water without irradiating the potato with the laser beam, the potato must be irradiated with light having a wavelength at which the laser beam is not easily attenuated by water. In this respect, it is convenient to use the fundamental wave of a YAG laser (wavelength of about 1 μm) because it absorbs less water. On the other hand, the wavelength is 2 μm or more (for example, CO ₂ Since light with a relatively long wavelength (such as a laser) has a relatively high absorption to water, it is more appropriate to use a method in which the skin is blown off by creating a flow of air rather than washing with water. Alternatively, a method of washing with water after laser irradiation may be employed. Alternatively, a method of rinsing the potato being irradiated with laser so as not to block the laser beam as much as possible, for example, irradiating the potato with water from the bottom of the potato while irradiating the laser beam from above the potato. You may take a method.
[0012]
Potato skin is collected and processed in a separate part from the potato body. The collection is performed, for example, by installing a collection container in a place where the potato skin is blown away with air. Alternatively, a belt conveyor may be prepared, and the potato skin blown off may be placed on the belt conveyor and moved to a desired collection place. The potato skins separated by washing with water may be transported to a collection site by forming a water channel. The object to be irradiated may be washed while irradiating with a laser or after the irradiation of the laser is completed.
[0013]
Since the potato is an irregular solid, it is necessary to rotate the potato relative to the laser beam in order to irradiate the entire surface of the potato with the laser beam. As a means of rotation, for example, a cylinder (referred to as a cylindrical roller in the present specification) that rotates about a rotationally symmetric axis is arranged in parallel and then rolled with potatoes. . By optimizing the radius of the cylinder, the potatoes rotate efficiently. Or rotation efficiency can also be raised by changing the rotational speed of each cylindrical roller, respectively. If the rotation directions of the rotating cylinders are the same, the potatoes move in one direction, so the rotating cylinder row plays the same role as the belt conveyor. Therefore, since potato peeling and transportation can be processed simultaneously, it is efficient when potatoes are peeled in large quantities.
[0014]
The laser beam may be irradiated from above the potato, from the gap between the rotating rows of cylinders, or both. Or you may irradiate from another direction.
[0015]
As potato rotating means, in addition to the above, spherical rotating elements may be arranged in a matrix and potatoes may be placed thereon. At this time, like the above-mentioned means, if the rotating directions are aligned, the potato can be transported in one direction. This is convenient when building a mass production line. Alternatively, the laser beam may be irradiated while rotating around the fork with the potato stabbed with a sharp fork.
[0016]
Alternatively, means for irradiating the entire surface of the irradiated object with a laser beam may be used instead of rotating. Specifically, for example, the irradiated object may be irradiated with a laser beam whose cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam is processed into a planar shape from above, below, right, left, or other directions. Alternatively, a laser beam whose cross-sectional shape is processed into a linear shape is irradiated on the irradiated object from the top, bottom, left, or right of the irradiated body or other directions, and the irradiated body is scanned relatively to the laser beam during that time. It is good to let them. A laser beam is irradiated on the entire surface of the irradiated object by scanning.
[0017]
What should be noted in this step is that the irradiated object is three-dimensional. Therefore, the energy density given to the irradiated object by the laser beam whose cross-sectional shape is processed into a linear or planar shape needs to be constant everywhere on the surface of the irradiated object. In order to obtain such a laser beam, it is only necessary to form a laser beam close to parallel light that has almost no cross-sectional shape as the laser beam advances. When such a laser beam is actually used for peeling, it is only necessary that the laser beam crossing the region where the irradiated object is present is substantially parallel light.
[0018]
At the current technical level, the energy of a high-power laser device that can be used in the industry is about 1 J / P, and even if it is very expensive, it is about 20 J / P. The energy density required to peel potatoes is at least a few J / cm ² Since it is necessary, it is not realistic to irradiate the whole potato with a laser beam processed into a planar shape at once. On the other hand, when the laser beam processed into a linear shape is irradiated while being scanned relative to the irradiated object, it is practical because an energy density sufficient to peel the potato skin can be obtained.
[0019]
For example, if a linear laser beam having a width of 0.05 cm and a length of 20 cm is produced using a 1 J / P laser device, it is 10 J / cm. ² The laser beam is obtained. This energy is sufficient to peel the potato. Since the optimum energy for skinning the potato varies depending on the laser device, the energy must be determined appropriately by the practitioner. This is because the optimum energy depends on the pulse width of the laser device (the emission time of one pulse in the pulsed laser device) and the wavelength of the laser.
[0020]
In the case of irradiating the irradiated body with a linear laser beam close to parallel light in FIG. 2 (see FIG. 2A) and in the case of irradiating the irradiated body with a linear laser beam that is not parallel light (FIG. 2 ( The difference from (B) is shown. First, it demonstrates along FIG. 2 (A). The laser beam emitted from the laser oscillator 201 is magnified by a concave (or convex) cylindrical lens 202. The laser beam expanded by the concave cylindrical lens 202 is processed into a parallel light beam by the convex cylindrical lens 203, so that the cross-sectional shape becomes a linear laser beam. An optical system that changes the beam width by combining the concave cylindrical lens 202 and the convex cylindrical lens 203 is generally called a beam expander.
[0021]
If this is the case, the energy density of the laser beam may not be sufficient. Therefore, by combining the convex cylindrical lens 204 and the concave cylindrical lens 205, the linear laser beam is made into a thin parallel light and irradiated to the three-dimensional irradiated object 206. . The combination of the convex cylindrical lens 204 and the concave cylindrical lens 205 narrows the beam width, which is also one of the beam expanders.
[0022]
Since the laser beam is processed into substantially parallel light by the combination of the beam expanders, the energy densities of the laser beams irradiated to the different points a and b on the surface of the irradiated object 206 are equal in order. The range until the laser beam exiting the concave cylindrical lens 205 reaches the floor 214 for arranging the irradiated object 206 is a portion called an irradiation region 213 in this specification. Next, description will be made with reference to FIG.
[0023]
The laser beam emitted from the laser oscillator 207 is magnified by a concave (or convex) cylindrical lens 208. Next, it is processed into parallel light by a convex cylindrical lens 209. The combination of the concave cylindrical lens 208 and the convex cylindrical lens 209 is also a beam expander. In order to increase the energy density of the linear laser beam, a convex cylindrical lens 210 is used. Thereby, since the linear laser beam is focused on a certain straight line 211, a very high energy density can be obtained on the straight line 211.
[0024]
The energy density of the laser beam at the point c on the surface of the irradiated object 212 not on the straight line 211 and the point d on the straight line 211 differs depending on the order. The irradiated object is placed on the floor 215. If the irradiated body 212 is a potato, the potato skin is not peeled off at the point c, but at the point d, the potato skin may be burnt and a fire may occur.
[0025]
Thus, the closer the laser beam used in the present invention is to parallel light, the better. Even if the laser beam to be used is not parallel light, it is sufficient if it is very close to parallel light. For example, in FIG. 2B, the focal length of the convex cylindrical lens 210 is made very long so that the focal position does not reach the irradiation region. Even in such a system, the object of the present invention can be achieved. When it is necessary to focus the laser beam due to the optical system, do not place an object at the focal point. If there is an object at the focal point, it may cause a fire.
[0026]
The method described above is a method in which the optical path of the laser beam is fixed and only the irradiated object is moved, but this is inferior in processing efficiency. This is because the region in which the irradiated object can be irradiated with the laser beam is very narrow. In this specification, a region where a laser beam can be irradiated onto an object to be irradiated is referred to as an irradiation region. Taking FIG. 2A as an example, the irradiation area indicates a lower area 213 from the cylindrical lens 205.
[0027]
A method for dramatically increasing the processing efficiency by increasing the volume of the irradiated region by moving the optical path of the laser beam relative to the irradiated object will be described below. By optimizing the state in which the irradiated object and the optical path of the laser beam are moving simultaneously, very efficient peeling can be performed. The movement here refers to a relative movement with respect to the ground.
[0028]
First, a method for moving the optical path of the laser beam will be described. The laser beam generally has straightness, and its path can be bent by using an optical system or the like. Therefore, there are two methods for moving the optical path of the laser beam: a method of quickly changing the traveling direction of the laser beam irradiated to the mirror by vibrating the mirror, and a method of using the flexibility of the optical fiber by passing the laser beam through the optical fiber. There are ways to move it. An apparatus that can vibrate a mirror like a pendulum is called a galvanometer.
[0029]
The present invention provides a method and apparatus for efficiently irradiating a potato surface with a laser beam using, for example, an optical fiber. The advantage of using an optical fiber is that the optical path of the laser beam can be easily changed and the shape of the laser beam can be easily changed.
[0030]
As a laser that can be applied to an optical fiber, for example, there is a YAG laser. The beam size of YAG laser varies, but if it has 1J / P output, it is about 1cm. ² It is an order. For example, an optical fiber having a diameter of about 1 mm is used. An optical fiber is like a thin fiber, and its inside is roughly divided into a three-layer structure. There is a portion called a core at the center of the optical fiber, and there is a portion called a clad having a refractive index smaller than that of the core. There is a protective film on the outside. The laser beam passes through a portion called the core. When the laser beam propagating through the core hits the clad, a phenomenon called total reflection occurs, and the laser beam stays in the core. By repeating total reflection, the laser beam propagates with almost no attenuation. A plurality of optical fibers having a diameter of 1 mm are collected into a bundle, and a YAG laser beam is incident on the fiber bundle in a form that matches the beam size of the YAG laser. This allows the YAG laser to pass through the optical fiber.
[0031]
Since the bundle of optical fibers is flexible, it is very easy to change the shapes of the light incident side and the light emitting side. The shape of the YAG laser used in this specification is circular, and is not a very efficient shape for irradiating the entire surface of the potato with the laser. By using an optical fiber for this, for example, the shape of the laser beam can be made linear.
[0032]
A method of obtaining a linear laser beam with an optical fiber will be described with reference to FIG. When the YAG laser 301 having a beam size of 1 cm in diameter is used, about 100 optical fibers 303 having a diameter of 1 mm are collected and bundled in a circular shape, and the YAG laser is incident on the bundle of optical fibers. At this time, in order to efficiently use the energy of the laser, it is effective to use the microlens array 302 including a plurality of fine convex lenses. By making each fine lens included in the microlens array 302 correspond to each optical fiber, the laser beam can be incident only on the core 303b of the optical fiber. (One of the optical fibers depicted in FIG. 3 is a cross-sectional view. The one covering the periphery of the core 303b is the clad 303a.) If the optical fiber has a diameter of about 1 mm, the diameter of the core is several hundred μm. It becomes. Therefore, in order to make the laser beam incident only on the core portion of the optical fiber, a convex lens having a diameter of 1 mm may be arranged corresponding to each optical fiber. The focal length of the lens is selected so that the light propagation efficiency of the optical fiber is the highest. That is, the focal length is set so that the laser beam enters the optical fiber at an angle satisfying the total reflection condition at the boundary between the clad 303a and the core 303b.
[0033]
When the shape of the optical fiber bundle 304 on the side from which the laser beam exits is, for example, linear, it is convenient because the potato can be efficiently irradiated with the laser beam. When irradiating a potato with a laser beam processed into a linear shape, by vibrating the optical fiber bundled in a linear shape using the flexibility of the optical fiber in a direction 305 perpendicular to the linear direction of the linear laser beam, The surface of the potato 309 can be efficiently irradiated with a laser beam. At this time, if the potato rotates while irradiating the laser beam, the entire potato surface can be irradiated with the laser beam.
[0034]
Since the laser beam 306 emitted from the optical fiber travels while expanding, the processing efficiency of the present invention is remarkably improved if the parallel light 308 is obtained by making each laser beam emitted from each optical fiber enter an appropriate convex lens 307. For simplicity, instead of providing a plurality of convex lenses, the spread of the laser light may be suppressed by making all laser beams emitted from the optical fiber enter one cylindrical lens.
[0035]
In addition to the above method, a linear laser beam may be moved relative to the ground by mirror vibration. In this case, after expanding the laser beam using a cylindrical lens or the like, the laser beam is squeezed and oscillated with an appropriate beam expander (in this case, one that narrows the beam width) to make it linear. The mirror may be placed at an appropriate place in the optical path of the laser beam. This method will be described in detail in Examples.
[0036]
In addition to the lasers mentioned above, glass lasers, CO ₂ Lasers, second harmonics, third harmonics, etc. of YAG lasers can be applied to the present invention. Moreover, it can be easily estimated by those skilled in the art that the present invention is not limited to potato peeling and can be used for similar foods. For example, the present invention can be used to remove taro skin, apple skin, cocoon skin, and the like. It can also be used to remove unnecessary things such as soil on the surface of food.
[0037]
That is, the present invention comprises means for irradiating an irradiated body with a laser beam having a linear cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiation region;
Means for irradiating the surface of the irradiated body with the laser beam while rotating the irradiated body;
Means for treating unwanted things removed from the irradiated body;
It is a laser irradiation apparatus characterized by having.
[0038]
Other configurations of the present invention include:
Means for irradiating the irradiated body with a laser beam whose cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiation region is linear;
Means for irradiating the surface of the irradiated body with the laser beam while rotating the irradiated body;
Means for treating unwanted things removed from the irradiated body;
Have
The laser irradiation apparatus is characterized in that the linear shape of the laser beam having a cross-sectional shape is formed through an optical fiber.
[0039]
Other configurations of the present invention include:
Means for irradiating the surface of the food covered with the skin with a laser beam whose cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiation region is linear;
Means for rotating the food material relative to the laser beam;
Means for treating the epidermis;
It is a laser irradiation apparatus characterized by having.
[0040]
Other configurations of the present invention include:
Means for applying moisture to the epidermis of food covered with the epidermis;
Means for irradiating the surface of the food material covered with the skin with a laser beam having a linear cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiated region, and ablating the skin;
Means for rotating the food material relative to the laser beam;
Means for treating the epidermis;
It is a laser irradiation apparatus characterized by having.
[0041]
Other configurations of the present invention include:
In the irradiation region, the surface of the food material covered with the skin is irradiated with a laser beam whose cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam is linear, or at the same time after the irradiation, water is supplied to the surface of the food material. Means for injecting
Means for rotating the food material relative to the laser beam;
Means for treating the epidermis;
It is a laser irradiation apparatus characterized by having.
[0042]
Other configurations of the present invention include:
Means for applying moisture to the epidermis of food covered with the epidermis;
In the irradiation region, the surface of the food material covered with the epidermis is irradiated with a laser beam whose cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam is linear, and the epidermis is ablated or simultaneously with the irradiation. Means for later spraying water onto the surface of the foodstuff;
Means for rotating the food material relative to the laser beam;
Means for treating the epidermis;
It is a laser irradiation apparatus characterized by having.
[0043]
In any of the above inventions, the laser beam is a YAG laser or YVO. _Four Laser or glass laser or CO ₂ If the laser is used, a large output can be easily obtained. Using a high-power laser is convenient for mass production because the processing efficiency increases. A plurality of lasers may be used. Alternatively, a plurality of different laser beams may be used.
[0044]
In any of the above-described inventions, the processing means may increase the processing efficiency if it includes an air injection device. Alternatively, if a device (water injection device) that is removed by washing with water is included, the processing efficiency may be improved.
[0045]
In any of the above-described inventions, it is preferable that the laser beam having a linear cross-sectional shape has a means for changing the traveling direction of the laser beam in the irradiation region because processing efficiency is increased. As a means for changing the traveling direction of the laser beam, a galvanometer or the like is appropriate.
[0046]
Other configurations of the present invention include:
Forming a laser beam having a linear cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiation region;
Irradiating the surface of the irradiated body with the laser beam while rotating the irradiated body;
A step of processing unnecessary things removed from the irradiated body;
It is a laser irradiation method characterized by having.
[0047]
Other configurations of the present invention include:
Forming a laser beam having a linear cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiation region;
Irradiating the surface of the irradiated body with the laser beam while rotating the irradiated body;
A step of processing unnecessary things removed from the irradiated body;
Have
The laser beam irradiation method is characterized in that the linear shape of the laser beam having a cross-sectional shape is formed through an optical fiber.
[0048]
Other configurations of the present invention include:
Forming a laser beam having a linear cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiation region;
Irradiating the surface of the food with the laser beam while rotating the food covered with an epidermis;
Treating the epidermis;
It is a laser irradiation method characterized by having.
[0049]
Other configurations of the present invention include:
Applying moisture to the skin of the food covered with the skin;
Forming a laser beam having a linear cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiation region;
Irradiating the surface of the food while rotating the food covered with the skin, and ablating the skin;
Treating the epidermis;
It is a laser irradiation method characterized by having.
[0050]
Other configurations of the present invention include:
Forming a laser beam having a linear cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiation region;
Irradiating the surface of the food material with the laser beam while rotating the food material covered with an epidermis, or after the irradiation, spraying water onto the surface of the food material;
Treating the epidermis;
It is a laser irradiation method characterized by having.
[0051]
Other configurations of the present invention include:
Applying moisture to the skin of the food covered with the skin;
Forming a laser beam having a linear cross-sectional shape in a plane perpendicular to the traveling direction of the laser beam in the irradiation region;
Irradiating the surface of the foodstuff with the laser beam while rotating the foodstuff covered with the epidermis, and spraying water onto the surface of the foodstuff at the same time as or after ablating the epidermis;
Treating the epidermis;
It is a laser irradiation method characterized by having.
[0052]
In any of the above laser irradiation methods, the laser beam is YAG laser or YVO. _Four Laser or glass laser or CO ₂ A laser is preferable because of high processing efficiency.
[0053]
In any of the above laser irradiation methods, it is preferable that the processing step includes a step of injecting air because the processing efficiency increases. Alternatively, it is preferable that the treatment step includes a step of injecting water because the treatment efficiency is increased.
[0054]
In any of the above laser irradiation methods, it is preferable to have a step in which the traveling direction of the laser beam whose cross-sectional shape is linear changes in the irradiation region, since the removal efficiency increases.
[0055]
DETAILED DESCRIPTION OF THE INVENTION
First, a method for removing the potato skin by irradiating a laser beam using potato as an object to be irradiated will be described.
[0056]
FIG. 1 shows a laser irradiation apparatus. As the laser oscillator 101, a laser oscillator that can generate a laser beam that can pass through the bundle 103 of optical fibers is used. For example, a YAG laser can be used. The laser beam emitted from the laser oscillator forms a plurality of focal points by the microlens array 102. A bundle of optical fibers 103 is arranged corresponding to each focal point immediately before or after the plurality of focal points, and a laser beam is incident on each of the optical fibers.
[0057]
Since the laser beam is usually circular or rectangular with an aspect ratio of one digit, the microlens array 102 is also made according to the shape of the laser beam. Prepare as many optical fibers as there are microlens arrays. The optical fiber is used for the purpose of changing the shape (generally circular or rectangular) of the laser beam.
[0058]
An efficient shape for separating the potato skin from the potato body is, for example, a linear laser beam. In order to obtain a linear laser beam, the laser beam output side of the bundle of optical fibers may be arranged linearly. At this time, it is preferable to make the energy uniform by alternately arranging optical fibers on which a relatively strong laser beam is incident and optical fibers on which a relatively weak laser beam is incident so that energy is not biased.
[0059]
The configuration of the apparatus until the linear laser beam is formed from the laser oscillator is the same as that shown in FIG. That is, the convex lens 104 is disposed immediately after the laser beam emitted from each optical fiber included in the optical fiber bundle 103 to process the laser light into parallel light.
[0060]
The peeled potato 105a from which mud has been removed by a washing machine or the like is placed on the belt conveyor 107a from the potato holder 106 and carried to the irradiation area 108. In the irradiation area 108, the potato carried on the belt conveyor 107a moves as it is to a table in which cylindrical rollers 109 rotating in the same direction are arranged in parallel. Adjacent cylindrical rollers 109 have an appropriate gap so that the potato 105b does not fall, and a laser beam is irradiated toward the potato 105b from these gaps.
[0061]
When the potato 105b passes over the cylindrical roller 109, the potato rotates well due to the action of the cylindrical roller 109. This irradiates the entire surface of the potato 105b with the laser beam. At the same time, the direction of potato movement is zigzag. At this time, it is preferable to provide a fall prevention wall (not shown) so that the potato 105b does not fall from the cylindrical roller 109.
[0062]
By rotating the potato with the cylindrical roller 109, the entire surface of the potato 105b can be irradiated with the laser beam. In order to efficiently irradiate the surface of the potato with the laser beam, if the linear laser beam is subjected to a pendulum motion along a direction perpendicular to the linear direction of the linear laser beam, the irradiation region 108 is expanded. Good. Alternatively, a plurality of linear laser beams may be provided. For example, with the configuration of the apparatus shown in FIG. 3, a plurality of linear laser beams may be formed and provided at several places above and below the cylindrical roller 109. At this time, the linear direction of the bundle of optical fibers arranged linearly and the bus bar of the cylindrical roller 109 are arranged in parallel. In this specification, it is assumed that the generatrix of the cylindrical roller 109 indicates a straight portion included in the curved surface of the cylindrical surface.
[0063]
In this way, the potato 105b skin is separated from the potato body. The separated potato skin 110 is blown away with air from the air jetting device 111 and collected in a waste collection container 112. The potato body 105c moves from the cylindrical roller 109 to the belt conveyor 107b, and is collected in a potato collection container 113.
[0064]
【Example】
[Example 1]
In this embodiment, an apparatus and method for forming a linear laser beam using the optical fiber shown in FIG. 3 will be described more specifically. This embodiment will be described with reference to FIG. In this embodiment, an example is shown in which a YAG laser 401 having an output of 4 kW is used as a light source. The beam spot of a YAG laser having a high output of about 4 kW is generally large and has a circular shape with a diameter of about 1 cm. The laser beam at the laser exit of the laser apparatus shown in this embodiment is also circular with a diameter of 1 cm.
[0065]
First, a circular laser beam having a diameter of 1 cm is passed through a microlens array 402 having a size of 1 mm square. The microlens array is of a size that allows all of the 1 cm diameter beam to enter. The focal length of each lens in the microlens array is set according to the NA of the optical fiber to be used. A multimode optical fiber is used as the optical fiber. The feature of the multimode optical fiber is that it is relatively easy to make a laser incident on the optical fiber. A single mode optical fiber, a graded index optical fiber, or the like may be used. When a single mode optical fiber is used, high accuracy is required when light is incident on the optical fiber.
[0066]
The incident side (a) of the bundle 403 of optical fibers has a shape (in the case of this embodiment, a circle) that matches the shape of the laser beam. On the other hand, the output side (b) of the bundle of optical fibers has, for example, a linear shape in order to efficiently irradiate the potato surface with the laser beam. Since the beam profile of the YAG laser used in this embodiment is near Gaussian, the output is higher toward the center of the circular laser beam. Therefore, when the optical fibers on the output side (b) of the bundle of optical fibers are arranged in a line, the optical fiber 405 on which a laser beam with a strong energy near the center is incident and the optical fiber 406 on which a relatively weak laser beam is incident on the other It is good to arrange energy alternately and average energy. Finally, in order to make the linear laser beam parallel light, the laser beam emitted from the optical fiber bundle 403 is made incident on the convex lens 404. A convex lens 404 is associated with each optical fiber. If the focal length of the convex lens 404 is set so as to eliminate the spread of the laser beam emitted from the optical fiber bundle 403, parallel light can be obtained.
[0067]
[Example 2]
In this embodiment, an apparatus and method for causing a linear laser beam to perform pendulum motion using a vibrating mirror will be described.
[0068]
A device called a galvanometer is known as a device that quickly vibrates a mirror around a certain axis and moves light quickly. FIG. 5 shows a galvanometer used in this embodiment.
[0069]
A galvanometer is a device that vibrates a mirror at high speed using electromagnetic force. Since it is commercially available, it can be easily obtained. The galvanometer 501 that can be used in this specification needs to have a mirror 503 larger than the size of the linear laser beam 502. The mirror 503 is vibrated around the rotation shaft 504 by the driving device 505. The apparatus for producing a linear laser beam may be one that uses the cylindrical lens shown in FIG. 2A or one that uses the optical fiber shown in FIG.
[0070]
Alternatively, a bundle of optical fibers formed in a linear shape may be vibrated using a galvanometer driving method. When this method is combined with the embodiment of the invention, it is convenient because the speed of oscillation of the laser beam emitted from the optical fiber can be increased. For example, a galvanometer may be used as means for pendulum movement of the optical fiber bundle 103 and the convex lens 104 along a curved line with arrows at both ends depicted in the center of FIG.
[0071]
Example 3
In the present embodiment, an example is shown in which the surface of a food material covered with an epidermis is moistened with moisture to promote ablation of the epidermis by laser irradiation. As described above, a laser in a certain wavelength region is highly absorbed by moisture. For example, CO whose wavelength is about 10 μm ₂ Laser is YAG laser or YVO _Four Compared with a laser, a glass laser, or the like, the absorption to moisture is extremely high. Therefore, when used in the apparatus and method shown in this embodiment, the treatment efficiency is high and it is preferable.
[0072]
This embodiment will be described with reference to FIG. Since FIG. 6 has almost the same configuration as the laser irradiation apparatus shown in FIG. 1, the same components as those shown in FIG.
[0073]
First, water discharged from the water injection device 601 is applied to the potato 105 a placed in the potato case 106. Since the purpose of applying water is to give moisture to the potato skin, it may be substituted by spraying steam on the potato. In this case, the temperature of the water vapor is set so as not to alter the potato.
[0074]
Moisturized potato 105a is peeled through a process similar to the method shown in the embodiment of the invention. Laser oscillators, for example, CO ₂ Use a laser. At this time, the skin may be washed away by the water injection device 602 shown in FIG. 6 instead of the air injection device 111. The water injection device 602 may apply water to the potato while irradiating the potato with a laser or after the laser irradiation.
[0075]
【The invention's effect】
The laser irradiation apparatus of the present invention makes it possible to efficiently peel the potato skin. Moreover, since the potato skin can be peeled off very thinly, food processing with less waste can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a laser irradiation apparatus
FIG. 2 is a diagram showing an example of forming a linear laser beam and irradiating the irradiated object with the laser beam.
FIG. 3 is a diagram showing an example of an apparatus for processing a laser beam into a linear shape using an optical fiber.
FIG. 4 is a diagram showing an example of an apparatus for processing a laser beam into a linear shape using an optical fiber.
FIG. 5 is a diagram showing an example in which a linear laser beam is vibrated using a galvanometer.
FIG. 6 is a diagram showing an example of a laser irradiation apparatus.
[Explanation of symbols]
101 Laser oscillator
102 Micro lens array
103 bundles of optical fibers
104 Convex lens
105 Potato
106 Potato container
107 belt conveyor
108 Irradiation area
109 cylindrical roller
110 Potato skin
111 Air injection device
112 Waste collection container
113 Potato Recovery Container
201 Laser oscillator
202 Concave cylindrical lens
203 Convex Cylindrical Lens
204 Convex cylindrical lens
205 Concave cylindrical lens
206 Object to be irradiated
207 Laser oscillator
208 Concave Cylindrical Lens
209 Convex cylindrical lens
210 Convex cylindrical lens
211 A straight line focused by a linear laser beam
212 Subject to be irradiated
213 Irradiation area
214 floors
215 floors
301 Laser oscillator
302 Micro lens array
303 bundle of optical fibers
303a clad
303b core
304 A bundle of optical fibers on the laser beam exit side
305 Direction perpendicular to the linear direction of the linear laser beam
306 Laser beam emitted from the optical fiber
307 Convex lens
308 Parallel light
309 Potato
401 YAG laser
402 Microlens array
403 bundle of optical fibers
404 Convex lens
405 Optical fiber on which a high-energy laser beam near the center is incident
406 Optical fiber on which a relatively weak laser beam is incident
501 Galvanometer
502 Linear laser beam
503 mirror
504 Rotation axis
505 Drive device
601 Water injection device
602 Water injection device

Claims (6)

The object covered with the epidermis is transported in one direction while being rotated, and the object is irradiated with the linear laser beam while the linear laser beam is moved in a pendulum direction along the direction perpendicular to the line direction. Removing the epidermis,
The linear laser beam is processed into a linear shape using an optical fiber,
The pendulum motion is performed by vibrating the optical fiber in a direction perpendicular to the linear direction using the flexibility of the optical fiber ,
The laser irradiation method, wherein the linear direction of the linear laser beam is perpendicular to the direction of the rotational movement, and the direction of the pendulum movement is parallel to the direction of the rotational movement . Oite to claim 1,
The irradiation of the linear laser beam is performed while water is sprayed on the object,
A laser irradiation method using a fundamental wave of a YAG laser as the linear laser beam. Oite to claim 1 or claim 2,
The laser irradiation method, wherein the object is any one of potato, taro, apple, and straw. The object covered with the epidermis is transported in one direction while being rotated, and the object is irradiated with the linear laser beam while the linear laser beam is moved in a pendulum direction along the direction perpendicular to the line direction. Removing the epidermis,
The linear laser beam is processed into a linear shape using an optical fiber,
The pendulum motion is performed by vibrating the optical fiber in a direction perpendicular to the linear direction using the flexibility of the optical fiber ,
The linear direction of the linear laser beam is perpendicular to the direction of the rotational movement, and the direction of the pendulum movement is parallel to the direction of the rotational movement . Manufacturing method. Oite to claim 4,
The irradiation of the linear laser beam is performed while water is sprayed on the object,
A method for manufacturing an article from which a skin has been removed, wherein a fundamental wave of a YAG laser is used as the linear laser beam. Oite to claim 4 or claim 5,
The said thing is any one of a potato, a taro, an apple, and a persimmon, The manufacturing method of the thing from which the epidermis was removed.

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