Refrigerator

Abstract

To provide a refrigerator that can be illuminated from a surface part, and comprises a shelf board on which fingerprints are hard to see even when they are attached to the surface part.SOLUTION: A refrigerator 2 comprises: a translucent shelf board 10; a light source 20 that radiates light from the rear side of the shelf board 10 to the front side; and a plurality of light diffusion dots 18 formed on at least one of an upper surface 10A or a lower surface 10B of the shelf board 10, where a size S of a gap between adjacent light diffusion dots 18 is equal to or smaller than a distance between ridges of a human finger.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a refrigerator having a shelf that functions as a light guide plate. [Background technology]

[0002] Some refrigerators are known to have light sources attached to translucent shelves, which emit light from the surfaces of the shelves to function as interior lighting. However, fingerprints on the surfaces of the shelves can be easily seen due to the lighting. To address this issue, refrigerators have been proposed that have a printed layer on the shelves where hydrophobic groups bonded to inorganic particles appear (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6818285 Summary of the Invention [Problem to be solved by the invention]

[0004] In the refrigerator described in the cited document 1, although the hydrophobic groups make it difficult for fingerprints to be left on the surfaces of the shelves, they cannot completely prevent fingerprints from being left on the shelves. As a result, as the refrigerator is used, fingerprints tend to be left on the surfaces of the shelves, making them more visible.

[0005] Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a refrigerator equipped with shelves that can be illuminated from the surface and that make fingerprints on the surface less visible. [Means for solving the problem]

[0006] In order to achieve the above object, the first aspect of the present invention is A translucent shelf board; a light source that irradiates light from the rear side surface of the shelf board to the front side; a plurality of light diffusing dots formed on at least one of the upper surface and the lower surface of the shelf board; Equipped with In this refrigerator, the size of the gap between adjacent light-diffusing dots is equal to or smaller than the distance between the ridges of a human finger.

[0007] Light emitted from the light source travels forward while being totally reflected by the top and bottom surfaces of the translucent shelf. If multiple light-diffusing dots are formed on the top or bottom surface of the shelf, the light is reflected by the dots and emitted to the outside from the surface opposite the surface on which the dots are formed. This allows the shelf to be used as lighting for the interior of the refrigerator, resulting in an interior with excellent design.

[0008] However, when a user's fingers touch the surface of the shelf, fingerprints may be left on the surface due to sebum or oil on the fingers, and the fingerprints may be visible. In particular, when light is guided onto the shelf, fingerprints become more noticeable due to differences in shadow.

[0009] In this embodiment, the light-diffusing dots are arranged so that the size of the gap between adjacent dots is equal to or smaller than the distance between the ridges of a finger. Therefore, light reflected from the light-diffusing dots is always present in the spaces between the ridges and enters the viewer's eyes. This light between the ridges makes it difficult to identify the outline of the ridges. Therefore, this embodiment can provide a refrigerator that can be illuminated from the surface and has shelves that make fingerprints on the surface less visible.

[0010] A second aspect of the present invention is a method for producing a composition comprising the steps of: The light diffusing dots are substantially circular, The diameter of the light diffusing dot is D, The distance between the centers of adjacent light diffusing dots is L, If the size of the gap is S, S = LD It is a refrigerator having the above relationship.

[0011] By using approximately circular light diffusion dots, multiple light diffusion dots can be easily and efficiently provided on the shelf board by printing, etc. The size of the gap between adjacent light diffusion dots can be reliably set using the formula S = LD.

[0012] A third aspect of the present invention is a method for producing a composition comprising the steps of: S ≦ 0.5mm It is a refrigerator having the above relationship.

[0013] The distance between the ridges of a human finger is said to be 0.4 to 0.5 mm, and by setting S ≦ 0.5 mm, the size of the gap S between the light diffusing dots can be reliably made equal to or less than the distance between the ridges of a human finger, resulting in a shelf board that is difficult to see even if fingerprints are attached to the surface.

[0014] A fourth aspect of the present invention is any one of the first to third aspects, The refrigerator has an arrangement density of the light diffusing dots of 0.39 or more.

[0015] In this embodiment, by setting the arrangement density of the light diffusing dots to 0.39 or more, it is possible to realize a shelf board that is reliably difficult to see even if fingerprints are attached to the surface.

[0016] A fifth aspect of the present invention is A translucent shelf board; a light source that irradiates light from the rear side surface of the shelf board to the front side; a plurality of light diffusing dots formed on at least one of the upper surface and the lower surface of the shelf board; Equipped with The refrigerator has an arrangement density of the light diffusing dots of 0.39 or more.

[0017] In this embodiment, by setting the density of the light-diffusing dots to 0.39 or more, it is possible to illuminate the shelf from the surface, and to realize a shelf that is reliably difficult to see even if fingerprints are attached to the surface.

[0018] A sixth aspect of the present invention is a method for manufacturing a semiconductor device comprising: A translucent shelf board; a light source that irradiates light from the rear side surface of the shelf board to the front side; a plurality of light diffusing dots formed on at least one of the upper surface and the lower surface of the shelf board; Equipped with The refrigerator has an illuminance of 220 Lx or less on the surface of the shelf opposite to the surface on which the light diffusion dots are arranged, and the arrangement density of the light diffusion dots is 0.15 or more.

[0019] The illuminance is 220 Lx or less, which is sufficient brightness to function as lighting for the interior of the refrigerator. According to this aspect, illumination from the surface is possible, and by limiting the illuminance of the light emitted from the surface, fingerprints on the surface can be made less visible even with a smaller arrangement density of the light diffusing dots. [Effects of the Invention]

[0020] As described above, the present invention can provide a refrigerator that can be illuminated from the surface and has shelves that make fingerprints on the surface less visible. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view schematically illustrating a refrigerator according to one embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing an outline of a shelf board of the refrigerator shown in FIG. [Figure 3] 3 is a side cross-sectional view schematically showing how light travels through the shelf board shown in FIG. 2. FIG. [Figure 4] 1 is a photograph showing the surface of shelf board samples 1 to 4 used in the test. [Figure 5A] FIG. 10 is a diagram showing dot patterns of light diffusing dots in Samples 1 to 4. [Figure 5B] 1 is a table showing the diameter of light diffusing dots in each area of Samples 1 to 4. [Figure 6A] FIG. 10 is an explanatory diagram of an equation for calculating the size S of the gap between adjacent light diffusing dots. [Figure 6B] 10 is a table showing the relationship between the gap between the light diffusing dots and the visibility of fingerprints. [Figure 7] 10 is a table showing the relationship between the illuminance of the surface and the visibility of fingerprints. [Figure 8A] FIG. 10 is a side cross-sectional view illustrating that fingerprints on the surface of a shelf board that does not have light-diffusing dots are easily visible. [Figure 8B] FIG. 10 is a cross-sectional side view illustrating that fingerprints on a shelf board having a plurality of light-diffusing dots arranged at a predetermined interval are less visible. [Figure 9A] 10 is a side cross-sectional view schematically showing how light travels when the size of the gap between adjacent light-diffusing dots is larger than the distance between ridges on a human finger. FIG. [Figure 9B] 10 is a side cross-sectional view schematically showing how light travels when the size of the gap between adjacent light diffusing dots is equal to or smaller than the distance between ridges on a human finger. FIG. [Figure 10] 10 is a table showing the relationship between the arrangement density of light diffusion dots and the visibility of fingerprints. [Figure 11] 10 is a graph showing the relationship between the illuminance on the surface of the shelf board and the density of the light diffusion dots. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The embodiments described below are intended to embody the technical concept of the present invention, and unless otherwise specified, the present invention is not limited to the following. Although the present invention may be divided into multiple embodiments, it is possible to combine the configurations shown in different embodiments or to partially replace the configurations. In the embodiments described below, descriptions of matters common to the previous embodiments will be omitted, and only differences will be described. In particular, similar effects due to similar configurations will not be mentioned in each embodiment.

[0023] The sizes and relative positions of components shown in the drawings may be exaggerated for clarity. In the following description and drawings, the refrigerator is placed on a horizontal surface, the side with the door is referred to as the front side, the opposite side as the rear side, and the left and right directions as viewed from the front side are referred to as left and right. In the drawings, the way light travels through the shelves is schematically shown with arrows of solid lines, dotted lines, or dashed dotted lines.

[0024] (Refrigerator and shelf board according to the first embodiment of the present invention) First, a refrigerator and a shelf according to one embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a perspective view schematically showing a refrigerator according to one embodiment of the present invention. Figure 2 is a perspective view showing an overview of a shelf of the refrigerator shown in Figure 1.

[0025] In the refrigerator 2 according to this embodiment, the refrigerator compartment 6 is disposed on the upper side and the freezer compartment is disposed on the lower side. FIG. 1 shows the refrigerator compartment 6 with the door 4, which opens and closes the front opening of the refrigerator compartment 6, open. The shelf 10 is a partition that divides the refrigerator compartment 6, which is the storage area of the refrigerator 2, into an upper and lower section. For example, the shelf 10 can be installed in the refrigerator compartment 6 by placing it on a support portion formed on the left and right inner surfaces of the refrigerator compartment 6 so that it protrudes inward. In this case, the shelf 10 is disposed so that both side surfaces 16 of the shelf 10 face the left and right inner surfaces of the refrigerator compartment 6. Note that the storage area in which the shelf 10 is disposed is not limited to the refrigerator compartment 6, and the shelf 10 can also be disposed in any other storage area, including the freezer compartment.

[0026] The shelf board 10 is made of a translucent material and functions as a light guide plate. The shelf board 10 can be made of a translucent resin material such as acrylic, or can be made of a translucent glass material. The shelf board 10 does not contain light-diffusing particles. The translucent shelf board 10 can be transparent or colored.

[0027] A light source body 22 equipped with a plurality of light sources 20 is attached to the rear side of the shelf board 10. The light source body 22 has a U-shaped or C-shaped side surface, and the rear end of the shelf board 10 is inserted into the U-shaped (C-shaped) opening of the light source body 22 so that the two fit together.

[0028] The light source body 22 is preferably made of an elastic material such as resin. The dimensions of the U-shaped (C-shaped) opening of the light source body 22 are formed slightly smaller than the outer shape of the shelf board 10, so that when the shelf board 10 is inserted into the U-shaped (C-shaped) opening of the light source body 22, the light source body 22 elastically deforms slightly outward. This allows the light source body 22 and the shelf board 10 to be tightly attached to each other, ensuring reliable attachment of the light source body 22 to the shelf board 10.

[0029] However, the shape of the light source body 22 is not limited to this. The light source body 22 may also have a flat plate shape. In that case, the light source body 22 can be attached to the shelf board 10 using adhesive or other fastening members. Furthermore, each light source 20 may also be attached directly to the shelf board 10.

[0030] Six light sources 20 are attached to the surface of the light source body 22 facing the rear side surface 12 of the shelf board 10. The six light sources 20 are arranged side by side in the width direction of the shelf board, and are designed to emit light from the rear side surface 12 of the shelf board 10 to the front side. LEDs that emit white light are used as the light sources 20. The light sources 20 are controlled to light up, for example, when the front door of the storage area in which the shelf board 10 is arranged is opened.

[0031] The light emitted by the LED is not limited to white light, and LEDs that emit light of any other color may be used depending on the application. The number of light sources 20 is not limited to six, and any number of light sources 20 greater than or equal to two may be arranged.

[0032] (How light travels on the shelf) Next, how light travels inside the shelf will be described with reference to Figure 3. Figure 3 is a side cross-sectional view that schematically shows how light travels inside the shelf shown in Figure 2. As indicated by the dotted arrows in Figure 3, light emitted from light source 20 travels forward while being totally reflected by upper surface 10A and lower surface 10B of shelf 10, and some of the light is emitted from front side surface 14.

[0033] In this embodiment, a plurality of light diffusing dots 18 are formed on the lower surface 10B of the shelf board 10. A portion of the light emitted from the light source 20 is reflected upward by the light diffusing dots 18 and emitted to the outside from the upper surface 10A of the shelf board 10. This functions as a light that illuminates stored items placed on the shelf board 10 from below.

[0034] It is also possible that light diffusing dots 18 are provided on the upper surface 10A of the shelf board 10. In this case, part of the light emitted from the light source 20 is reflected downward by the light diffusing dots 18 and emitted to the outside from the lower surface 10B of the shelf board 10. This functions as lighting that illuminates stored items placed on the lower side of the shelf board 10. Furthermore, it is also possible that light diffusing dots 18 are provided on both the upper surface 10A and the lower surface 10B of the shelf board 10. In this case, it functions as double-sided lighting in which light is emitted from both the upper surface 10A and the lower surface 10B of the shelf board 10. The light diffusing dots 18 can be formed on the upper surface 10A and the lower surface 10B of the shelf board 10 by printing, for example.

[0035] As described above, shelf 10 is made of a translucent acrylic or glass material, but when a user touches it with their fingers, sebum and oil from the fingers adhere to the surface of shelf 10. Fingerprints on top surface 10A or bottom surface 10B of shelf 10 are particularly easy to see. When light source 20 is turned on and surfaces 10A and 10B are used as illumination, fingerprints become even more easily visible.

[0036] To address this issue, the inventors focused on light-diffusing dots and investigated shelf boards that would make fingerprints less visible. Specifically, they produced prototype shelf board samples with light-diffusing dots of various dot patterns, and tested whether fingerprints were visible by attaching fingerprints to the surfaces, thereby investigating dot patterns that would make fingerprints less visible.

[0037] (Shelf sample) The shelf board samples used in the test will be described with reference to Figures 4, 5A, and 5B. Figure 4 is a photograph showing the surface of shelf board samples 1 to 4 used in the test. Figure 5A is a diagram showing the dot patterns of light diffusing dots in samples 1 to 4. Figure 5B is a table showing the light diffusing dot diameters in each area of samples 1 to 4.

[0038] In the four samples 1 to 4, light diffusing dots are formed on the underside of the shelf board as shown in Fig. 3. The dot patterns of the light diffusing dots formed on samples 1 to 4 are as follows.

[0039] In Sample 1, in all areas, approximately circular light diffusing dots are formed at the vertices of an equilateral triangle with a side length of 1.7 mm, with the center at the vertex. In Sample 2, in all areas, approximately circular light diffusing dots are formed at the vertices and center of a square with a side length of 1 mm, with the center at the vertex and center. In Sample 3, in all areas, approximately circular light diffusing dots are formed at the vertices of an equilateral triangle with a side length of 2.3 mm, with the center at the vertex. In Sample 4, in all areas, approximately circular light diffusing dots are formed at the vertices of an equilateral triangle with a side length of 1.2 mm, with the center at the vertex.

[0040] Samples 1 to 4 are divided into six areas from the rear to the front, area A to area F. In Samples 1, 3, and 4, the dot diameter of the light diffusing dots increases from area A to area F (from the rear to the front), from 0.5 mm, 0.55 mm, 0.6 mm, 0.7 mm, 0.8 mm, to 0.9 mm. In Sample 2, on the other hand, the dot diameter of the light diffusing dots is 0.5 mm in all areas.

[0041] By attaching a light source to the rear side of shelf samples 1 to 4 and irradiating them, light is emitted from the top surface of shelf samples 1 to 4. In the fingerprint visibility test described below, 10 inspectors visually inspected shelf samples 1 to 4 from the top side. If none of the inspectors could visually recognize the fingerprint, the fingerprint was judged as "not visible," and if at least some of the inspectors could visually recognize the fingerprint, the fingerprint was judged as "visible."

[0042] As a preliminary test, fingerprints were left by touching the top surfaces of Samples 1 to 4 with a finger coated with salad oil, and salad oil was evenly applied to the top surfaces of Samples 1 to 4 with paper. Then, the light source was turned on as described above to check whether the fingerprints were visible. As a result, it was determined that the fingerprints were visible, but the areas where the oil was applied were not clearly visible. This also made it clear that fingerprints tend to be easily visible.

[0043] Example 1 Next, a fingerprint was attached to all areas A to F of samples 1 to 4, and the light source was turned on to conduct a fingerprint visibility test to determine whether the fingerprint was visible. In Example 1, attention was paid to the size S of the gap between adjacent light diffusing dots, and whether the fingerprint was visible or not was confirmed. This will be explained with reference to FIGS. 6A, 6B, and 7. FIG. 6A is an explanatory diagram of a formula for calculating the size S of the gap between adjacent light diffusing dots. FIG. 6B is a table showing the relationship between the gap between light diffusing dots and fingerprint visibility. FIG. 7 is a table showing the relationship between the illuminance of the surface and fingerprint visibility.

[0044] As shown in FIG. 6A , in Samples 1, 3, and 4, light diffusing dots with a dot diameter D are formed at each vertex of an equilateral triangular dot pattern, with the vertex position as center C. The center-to-center distance L between adjacent light diffusing dots is equal to the length of one side of the equilateral triangle. In Sample 2, light diffusing dots with a dot diameter D are formed at each vertex and the center of a square dot pattern, with the vertex and center position as centers C. The center-to-center distance L between adjacent light diffusing dots is equal to the length of one side of the square and the distance between the vertex and the center. If the length of one side of the square is N, the distance between the vertex and the center is N×SQR(2) / 2, which is approximately 70% of the length of one side of the square.

[0045] If the length of one side of the equilateral triangle, the length of one side of the square, and the distance between the vertex and the center of the square are the center-to-center distance L, the dot diameter is D, and the size of the gap between adjacent light diffusing dots is S, the size of the gap S can be calculated as S = LD. The size of the gap S in each of areas A to F of each of samples 1 to 4 is shown in the table in Figure 6B.

[0046] In the table in Figure 6B, the sample areas where the 10 testers judged the fingerprints to be invisible are colored (inked). In Sample 2, fingerprints were judged to be invisible in all areas A to F.

[0047] The illuminance of light emitted from the top surface of shelf samples 1 to 4 varies depending on the distance from the light source and the proportion of the area occupied by the formed light-diffusing dots. Figure 7 shows the measurement results of the illuminance of light on the top surface in areas A to F of each of samples 1 to 4. Generally, there is a tendency for the illuminance to decrease from the rear side closer to the light source 20 to the front side (A to F side), but in samples 1, 3, and 4, the dot diameter increases from the rear side to the front side (A to F side), making this tendency even more pronounced.

[0048] Even with the same distribution of light diffusing dots, it is thought that fingerprints will be more easily visible when the illuminance of light emitted from the top surface is higher. Taking these factors into consideration and referring to Figures 6B and 7, the following became clear.

[0049] In Sample 2, where the gap size S between adjacent light diffusion dots is 0.5 mm and 0.2 mm, it was determined that fingerprints were not visible in any area. In particular, fingerprints were not visible even in Area A, where the illuminance was as high as 1560 Lx. On the other hand, for example, in Sample 4, where the gap size S is 0.7 mm, fingerprints were visible in Area A, where the illuminance was 1300 Lx.

[0050] In area A where light with a high illuminance exceeding 1000 Lx is emitted, fingerprints are not visible in sample 2 where the size S of the gap between adjacent light diffusing dots is 0.5 mm and 0.2 mm, but are visible in sample 2 where the size S is 0.7 mm. The reason for this difference in fingerprint visibility will be considered below.

[0051] (Relationship between the size of the gap between adjacent light-diffusing dots and the visibility of fingerprints) Next, the relationship between the size S of the gap between adjacent light diffusing dots and the visibility of fingerprints will be considered with reference to Figures 8A, 8B, 9A, and 9B. Figure 8A is a side cross-sectional view illustrating that fingerprints on the surface of a shelf board without light diffusing dots are easily visible. Figure 8B is a side cross-sectional view illustrating that fingerprints on the surface of a shelf board on which a plurality of light diffusing dots are arranged at a predetermined gap interval are difficult to see. Figure 9A is a side cross-sectional view schematically illustrating how light travels when the size of the gap between adjacent light diffusing dots is larger than the spacing between ridges on a human finger. Figure 9B is a side cross-sectional view schematically illustrating how light travels when the size of the gap between adjacent light diffusing dots is equal to or smaller than the spacing between ridges on a human finger. In the drawings, the cross-sectional shapes of ridges that are approximately perpendicular to the extension direction of the ridges are shown as circles.

[0052] As shown in Figure 8A, when a fingerprint is placed on the surface of a shelf board that does not have light-diffusing dots, the surrounding light is reflected by the fingerprint, and the reflected light enters the viewer's eyes (see the solid arrow), allowing the fingerprint's shape to be recognized. In particular, when the light source is turned on and the light is guided onto the shelf board, the fingerprint becomes more visible due to the difference in shading.

[0053] As shown in Figure 8B, even on a shelf with multiple light-diffusing dots arranged at regular intervals on its underside, ambient light is reflected by fingerprints and enters the viewer's eyes. Furthermore, with this shelf, ambient light enters the shelf from the top, is reflected by the light-diffusing dots, and exits upward from the top (see the dotted arrow). Furthermore, when the light source is turned on, light from the light source is reflected by the light-diffusing dots and exits upward from top surface A (see the colored arrow).

[0054] As a result, the light reflected from the fingerprint ridges (see solid arrows), the light incident from above that is reflected by the light diffusion dots (see dotted arrows), and the light guided to the shelf that is reflected by the light diffusion dots (see colored arrows) all enter the viewer's eyes, making the fingerprint difficult to see.

[0055] Of particular note is the relationship between the spacing between fingerprint ridges and the spacing between light diffusing dots. As shown in Figures 9A and 9B, in areas where light-diffusing dots are present, light is reflected by the light-diffusing dots and emitted from the top surface of the shelf board, but no reflected light occurs in the spaces between the light-diffusing dots. Therefore, as the gap between adjacent light-diffusing dots increases, the area where no reflected light occurs expands. As shown in Figure 9A, if the size S of the gap between adjacent light-diffusing dots is larger than the distance T between the ridges of a finger, there may be no reflected light from the light-diffusing dots between the ridges. In such a space, the outer edges of the ridges, formed by the reflected light from the surrounding light hitting the ridges, become clearly visible.

[0056] On the other hand, as shown in Figure 9B, when the size S of the gap between adjacent light diffusing dots is equal to or less than the distance T between the ridges of the finger, no space between the ridges is created where no light is reflected from the light diffusing dots. Light reflected from the light diffusing dots is always present in at least a portion of the space between the ridges. Because the light reflected from the light diffusing dots in the space between the ridges enters the viewer's eyes, it becomes difficult to identify the outer edge of the ridge, which is formed by the light reflected from the surrounding light hitting the ridge.

[0057] The spacing between fingerprint ridges is generally said to be 0.4 to 0.5 mm. Therefore, in Sample 2, where the size S of the gap between adjacent light diffusing dots is 0.5 mm and 0.2 mm, it is less than the spacing T of the finger ridges. Therefore, even in Area A where light with an illuminance exceeding 1000 Lx is emitted, the fingerprint is not visible. On the other hand, in Area A of Sample 4, where the size S of the gap is 0.7 mm, it is larger than the spacing T of the finger ridges, and the fingerprint is visible in Area A where light with an illuminance exceeding 1000 Lx is emitted.

[0058] As described above, Example 1 has demonstrated that when the size S of the gap between adjacent light diffusing dots is equal to or smaller than the distance between ridges on a human finger, fingerprints are not visible even on a surface onto which light with an illuminance exceeding 1000 Lx is emitted. Specifically, it has been demonstrated that when the size S of the gap is 0.5 mm or less, fingerprints are not visible.

[0059] As described above, based on Example 1, the refrigerator 2 according to an embodiment of the present invention comprises a translucent shelf 10, a light source 20 that irradiates light from the rear side of the shelf 10 to the front, and a plurality of light diffusion dots 18 formed on at least one of the upper surface 10A or the lower surface 10B of the shelf 10, and the size S of the gap between adjacent light diffusion dots 18 is equal to or less than the distance between the ridges of a human finger.

[0060] This allows for illumination from surfaces 10A and 10B, and provides refrigerator 2 equipped with shelves 10 that are difficult to see even if fingerprints are left on surfaces 10A and 10B.

[0061] Furthermore, if the light diffusion dots 18 are approximately circular, the diameter of the light diffusion dots 18 is D, the distance between the centers of adjacent light diffusion dots 18 is L, and the size of the gap is S, then S can be calculated as S = LD.

[0062] By using the approximately circular light diffusion dots 18, it is possible to easily and efficiently provide a plurality of light diffusion dots 18 on the shelf board 10 by printing or the like. The above formula S = LD allows the size of the gap S between adjacent light diffusion dots 18 to be reliably set.

[0063] The spacing between ridges on a human finger is said to be 0.4 to 0.5 mm, and by setting S ≦ 0.5 mm, the size of the gap S between the light diffusing dots 18 can be reliably set to be equal to or less than the spacing between ridges on a human finger. This makes it possible to realize a shelf board that is difficult to see even if fingerprints are attached to the surface. Note that since the spacing between ridges varies from person to person, it is more preferable to set S ≦ 0.4 mm, and even more preferable to set S ≦ 0.3 mm.

[0064] Example 2 In Example 2, a fingerprint visibility test was conducted using Samples 1 to 4 described above, focusing on the density of light diffusion dots to check whether fingerprints were visible. This will be explained below with reference to Fig. 10. Fig. 10 is a table showing the relationship between the density of light diffusion dots and fingerprint visibility.

[0065] The arrangement density of light diffusing dots is the ratio of the area occupied by the light diffusing dots to the total area of the surface on which the light diffusing dots are arranged. As described above, it is thought that the arrangement density of light diffusing dots increases when the size S of the gap between adjacent light diffusing dots is small, so there is a certain degree of correlation between the two. However, there are various dot patterns, including equilateral triangles and squares, and there are also various combinations of dot center distances and dot diameters. Therefore, the arrangement density of light diffusing dots is not uniquely determined by the size of the gap between the light diffusing dots.

[0066] As shown in Fig. 10, in the case of sample 2 in which the density of light diffusing dots is 0.39, it was determined that fingerprints were not visible in all areas A to F. In particular, it was determined that fingerprints were not visible even in area A where the illuminance from above exceeded 1000 Lx.

[0067] Even if the density of light diffusing dots is 0.39 or higher, the size S of the gap between adjacent light diffusing dots is not necessarily smaller than the distance between the ridges of a human finger. However, statistically speaking, it is highly likely that reflected light from the light diffusing dots exists in the spaces between the ridges. This makes it difficult to identify the outer edges of the ridges, which are formed by the reflected light from surrounding light hitting the ridges, making it difficult to visually recognize the fingerprint.

[0068] As described above, based on Example 2, the refrigerator 2 according to an embodiment of the present invention comprises a translucent shelf 10, a light source 20 that irradiates light from the rear side surface 12 of the shelf 10 to the front side, and a plurality of light diffusion dots 18 formed on at least one of the upper surface 10A or the lower surface 10B of the shelf 10, and the arrangement density of the light diffusion dots 18 is 0.39 or more.

[0069] In this way, by setting the arrangement density of the light diffusing dots 18 to 0.39 or more, it is possible to illuminate the shelf board 10 from the surfaces 10A and 10B, and to realize a shelf board 10 that is reliably difficult to see even if fingerprints are attached to the surfaces 10A and 10B. The configuration shown in Example 2 can be combined with the configuration shown in Example 1 above.

[0070] Example 3 As shown in the table in Figure 7, when the illuminance from the top surface of the shelf is less than 1000 Lx, fingerprints may not be visible even if the light diffusing dots do not satisfy the requirements verified in Examples 1 and 2 above. An illuminance of 1000 Lx is a level at which delicate work can be performed, and if the condition of the items stored inside the refrigerator 2 is to be checked, a lower illuminance will not cause any problems. For example, the recommended illuminance for a living room is 100 to 200 Lx.

[0071] Next, the density of light diffusing dots at which fingerprints are not visible in relation to the illuminance will be considered with reference to Fig. 11. Fig. 11 is a graph showing the relationship between the illuminance on the surface of the shelf board and the density of light diffusing dots. In the graph of Fig. 11, the horizontal axis represents the density of light diffusing dots, and the vertical axis represents the illuminance (Lx) from the top surface 10A.

[0072] As is clear from the tables of Fig. 7 and Fig. 10 and the graph of Fig. 11, when the illuminance from the upper surface 10A is 220Lx or less, fingerprints are not visible in all samples 1 to 4. In this case, the arrangement density of the light diffusing dots is 0.15 or more. When the illuminance on the upper surface is 220Lx or less, fingerprints attached to the sample are not visible if the arrangement density of the light diffusing dots is 0.15 or more.

[0073] As described above, based on Example 3, the refrigerator 3 according to an embodiment of the present invention comprises a translucent shelf 10, a light source 20 that irradiates light from the rear side surface 12 of the shelf 10 to the front, and a plurality of light diffusing dots 18 formed on at least one of the top surface 10A or bottom surface 10B of the shelf 10, wherein the illuminance of the light source 20 on the surface 10A (10B) opposite to the surface on which the light diffusing dots 18 of the shelf 10 are arranged is 220 Lx or less, and the arrangement density of the light diffusing dots 18 is 0.15 or more.

[0074] Even if the illuminance is 220 Lx or less, it functions sufficiently as illumination for the interior of the refrigerator 2. Illumination from the surfaces 10A and 10B is possible, and by limiting the illuminance of the light emitted from the surfaces 10A and 10B, fingerprints on the surfaces 10A and 10B can be made invisible even with a smaller arrangement density of the light diffusing dots. The configuration shown in Example 3 can be combined with the configuration shown in Example 1 and / or Example 2 above.

[0075] In the above Examples 1 to 3, a visual fingerprint test is conducted on the upper surface 10A of the shelf board 10, but this is not limited to this, and the same applies when light diffusing dots 18 are provided on the upper surface 10A and a visual fingerprint test is conducted on the opposite lower surface 10B.

[0076] Although the embodiments and modes of implementation of the present invention have been described, the disclosed contents may vary in the details of the configuration, and changes in the combination and order of elements in the embodiments and modes of implementation may be realized without departing from the scope and spirit of the claimed invention. [Explanation of symbols]

[0077] 2. Refrigerator 4 doors 6 Refrigerator 10 shelves 10A top 10B Bottom 12 Rear side 14 Front side 16 Sides on both sides 18 light diffusion dots 20 light source 22 Light source main body

Claims

1. A translucent shelf board; a light source that irradiates light from the rear side surface of the shelf board to the front side; a plurality of light diffusing dots formed on at least one of the upper surface and the lower surface of the shelf board; Equipped with The refrigerator is characterized in that the size of the gap between adjacent light diffusing dots is equal to or smaller than the distance between ridges of a human finger.

2. The light diffusing dots are substantially circular, The diameter of the light diffusing dot is D, The distance between the centers of adjacent light diffusing dots is L, If the size of the gap is S, S = L-D 2. The refrigerator according to claim 1, wherein the relationship is:

3. S≦0.5 mm 3. The refrigerator according to claim 2, wherein the relationship is:

4. 4. The refrigerator according to claim 1, wherein the light diffusion dots have an arrangement density of 0.39 or more.

5. A translucent shelf board; a light source that irradiates light from the rear side surface of the shelf board to the front side; a plurality of light diffusing dots formed on at least one of the upper surface and the lower surface of the shelf board; Equipped with A refrigerator characterized in that the light diffusion dots are arranged at a density of 0.39 or more.

6. A translucent shelf board; a light source that irradiates light from the rear side surface of the shelf board to the front side; a plurality of light diffusing dots formed on at least one of the upper surface and the lower surface of the shelf board; Equipped with A refrigerator characterized in that the illuminance from the light source on the surface of the shelf opposite to the surface on which the light diffusion dots are arranged is 220 Lx or less, and the arrangement density of the light diffusion dots is 0.15 or more.

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