JPH0530801U - Resin laminated board for optical filter - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a resin laminated plate for an optical filter, which is easy in production control and inventory control and does not cause malfunction in the bent portion even if bending is performed. [Structure] One or a plurality of transparent resin sheets (non-filter sheet) (2) (3) having no optical filter function are laminated on both sides of a resin sheet (filter sheet) (1) having an optical filter function, respectively. It becomes.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a resin laminated plate for an optical filter that selectively transmits or absorbs light in a predetermined wavelength range.

[0002]

[Prior Art]

 Recently, various resin optical filters have been used in electronic devices and various other applications. For example, near-infrared transmission filters for light-emitting and light-receiving elements for TVs, videos, touch panel bezel materials, security camera boxes, etc., near-infrared absorption filters for image scanners, electronic copiers, bar code readers, facsimiles, etc. A visible light transmission filter for image decomposition is used for the camera, and a neutral filter (ND filter) for light amount correction is used for the camera, video, and the like.

The resin optical filters as described above are generally disclosed in JP-A-60-43605, JP-A-61-277903, JP-A-62-903, and JP-A-62-187302. As can be seen in the publications, etc., a coloring agent for absorbing near-infrared rays, a coloring agent for transmission, etc. is added to a resin according to the purpose to impart a desired filter function.

[0006] Thus, there are cases where it is required to increase the wall thickness of the optical filter as described above. In this case, however, in the conventional case, a thin color filter to which a predetermined coloring agent is added has a filter function. A unit resin sheet was formed and a plurality of such unit sheets were laminated to produce a thick optical filter laminate. Therefore, there are the following drawbacks.

[0005]

[Problems to be solved by the device]

 That is, the required amount of coloring agent mixed in the resin to give the optical resin filter a proper filter function is constant per unit area of the filter through which light passes, and the total thickness of the filter is Not done. In other words, even if the filters have different total thicknesses, the same filter function can be exhibited if the amount of coloring material contained in the unit area of the filter is constant. Therefore, in a conventional optical filter in which each of the laminated unit resin sheets has a filter function, the amount of coloring material added to the unit sheet changes with the total thickness of the optical filter, and the production management, There was a drawback that inventory management was troublesome. Specifically, when the unit sheet has a thickness of 0.5 mm and an optical filter having a thickness of 1 mm is manufactured by laminating two unit sheets, the required amount of coloring material as an optical filter is 1 unit per unit area. Then, the amount of colorant added and mixed in each unit sheet is 0.5 per unit area. On the other hand, when an optical filter with a thickness of 2 mm is manufactured by using four unit sheets, the amount of colorant added to each unit sheet is 0.25 per unit area, which means that the unit sheets have the same thickness. However, the required amount of colorant was different depending on the difference in overall thickness.

Moreover, in the conventional laminated structure of unit resin sheets each having a filter function, the optical resin filter (10) is formed by bending by thermoforming like the bezel material for a touch panel illustrated in FIG. 4, for example. When it is used as a product, it is stretched on the outer side and contracted on the inner side in the bent part (11), causing a partial imbalance in the colorant amount. As a result, there is a drawback that the filter function is changed or abnormal at this bent portion, which causes malfunction.

The present invention has been made in order to solve the above drawbacks, and is for an optical filter which is easy to manage in production and inventory, and which does not cause a malfunction in a bent portion even if bending is performed. The purpose is to provide a resin laminate.

[0008]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention relates to the amount of coloring agent mixed in resin for imparting a filter function to the amount per unit area without depending on the final thickness of the optical filter. In view of this, by configuring only a part of the optical filter in the thickness direction with a resin sheet having a filter function, it is possible to secure the required amount of colorant, while other parts have a filter function. It is a transparent resin sheet that is not used, and the overall thickness is adjusted by adjusting the thickness of this sheet. In addition, the resin sheet having the above-mentioned filter function is to be positioned in the middle portion in the thickness direction where there is little change in elongation and contraction due to bending.

That is, according to the present invention, referring to the reference numerals of the drawings, one or a plurality of resin sheets having an optical filter function (hereinafter referred to as “filter sheet”) (1) having no optical filter function are provided. A gist of a resin laminated plate for an optical filter is characterized in that a plurality of transparent resin sheets (hereinafter referred to as “non-filter sheet”) (2) and (3) are laminated respectively.

[0010]

[Action]

 The adjustment of the total thickness of the laminated plate for an optical resin filter can be adjusted by adjusting the thickness of the non-filter sheets (2) and (3) on both sides. Since the amount of colorant contained in the unit area of the laminate is determined by the filter sheet (1), the filter sheet (1) contains a certain amount of colorant even if the thickness of the entire laminate changes. Therefore, there is no inconvenience of changing the amount of colorant added to the filter sheet (1) every time the total thickness changes.

Further, since the non-filter sheets (2) and (3) are laminated on both sides of the filter sheet (1), the filter sheet (1) should be located at the middle portion in the thickness direction of the entire laminated plate. Therefore, even when bending is performed by thermoforming, the expansion and contraction deformation amount of the filter sheet (1) is suppressed as compared with the case where it is located on the outermost side or the innermost side, and in the thickness direction of the filter sheet (1). The occurrence of imbalance in the amount of colorant is suppressed.

[0012]

【Example】

 Next, an embodiment of this invention will be described.

In FIG. 1, (1) is a filter sheet, and (2) and (3) are non-filter sheets.

The filter sheet (1) is composed of a transparent resin as a base and a predetermined amount of a coloring agent for imparting a desired optical filter function according to the purpose, and is mixed in a predetermined amount. The thickness is set to about 0.5 mm. As the base resin, a polyvinyl chloride resin excellent in calender moldability is preferably used. On the other hand, as an example of the coloring agent, when the filter sheet (1) is intended to transmit near infrared rays, for example, Solvent Green 20 or Solvent Green 28 as disclosed in JP-A-61-277903. The near infrared transmitting agent may be used. When the filter sheet (1) is intended to absorb near infrared rays, for example, anthraquinone colorants and phthalocyanines as disclosed in JP-A-60-43605 and JP-A-62-903. A near infrared absorbing agent such as a colorant may be used. Further, in the case of aiming at transmission in the visible light range, indigo or azo dyes may be used, and other various coloring agents may be used depending on the intended filter function.

The non-filter sheets (2) and (3) are resin sheets that do not have an optical filter function, and are formed of a transparent resin to allow the transmission of light. Here, as the transparent resin, a polyvinyl chloride resin which is also excellent in calender moldability can be preferably used. The thickness is preferably about 0.2 to 0.5 mm. Then, the non-filter sheets (2) and (3) are bonded to both surfaces of the filter sheet (1) by means of heat fusion or the like, thereby forming a resin laminated plate for an optical filter. The thickness of the laminated plate can be changed by changing the thickness of the non-filter sheets (2) and (3), and it is not necessary to change the thickness of the filter sheet (1). As long as the thickness of the filter sheet (1) is constant, the colorant content contained in the unit area of the laminated plate is constant even if the thickness of the non-filter sheets (2) and (3) changes. Even if the total thickness is different, the same filter function is exhibited.

Further, the filter sheet (1) is sandwiched between the upper and lower non-filter sheets (2) and (3), and is positioned in the middle in the thickness direction of the laminated plate. When the optical filter resin laminate shown in FIG. 1 is bent by thermoforming as shown in FIG. 3, the outer side of the filter sheet (1) is extended and the inner side is extended at the bent portion (4). Contracts, but the amount of expansion and contraction at the bent portion (4) is smaller than that at the outermost or innermost position. Therefore, no significant imbalance occurs in the colorant distribution in the filter sheet (1). From this point of view, it is necessary to set the thicknesses of the non-filter sheets (2) and (3) on both sides to be equal and to position the filter sheet (1) at the exact center of the laminate in the thickness direction. (1) is the neutral surface, and it is most preferable because neither expansion nor contraction occurs during bending.

FIG. 2 shows a modified example of the present invention, in which each of the non-filter sheets (2) and (3) is composed of a plurality of thin unit sheets (2a) (2b) (3a) (3b). It is a thing. With such a configuration, the thickness of the entire laminated plate can be adjusted by setting the number of unit sheets, while one kind of unit sheet may be manufactured as the material for the non-filter sheets (2) and (3). Therefore, production management and inventory management can be made more efficient. In FIG. 2, parts having the same names as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

Although only one filter sheet (1) is used in the illustrated embodiment, a plurality of filter sheets may be laminated and the non-filter sheets (2) and (3) may be laminated on both surfaces thereof.

[0019]

[Effect of the device]

 According to this invention, the transparent non-filter sheet is laminated on both sides of the filter sheet according to the above, so that the filter sheet secures the absolute amount of the coloring agent necessary for exhibiting the optical filter function, The overall thickness of the plate can be changed by adjusting the thickness of the non-filter sheet. Therefore, even if the thickness of the laminated plate is different, it is only necessary to manufacture a filter sheet with a constant colorant amount and thickness, which can facilitate production control and inventory control, and improve efficiency. .

Further, since the filter sheet is located in the middle in the thickness direction of the laminated plate due to the presence of the non-filter sheet on both sides, even when the laminated plate is bent by thermoforming, the elongation of the filter sheet is increased. The amount of shrinkage deformation can be suppressed, and the inconvenience of causing imbalance in the colorant distribution of the filter sheet and lowering the filter function or causing malfunctions can be eliminated.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a modified example of the present invention.

3 is an enlarged cross-sectional view of a bent portion when the laminated plate shown in FIG. 1 is formed by bending.

FIG. 4 is a cross-sectional view of a bezel material for a touch panel as an application example of an optical filter.

[Explanation of symbols]

 1 ... Filter sheet 2, 3 ... Non-filter sheet

Claims (1)

[Scope of utility model registration request] 1. A transparent resin sheet (2) (3) having no optical filter function is laminated on both surfaces of a resin sheet (1) having an optical filter function, respectively. Resin laminated plate for optical filters.