Display devices and gaming machines

Abstract

To provide a display device that can express a displayed pattern with more varied color combinations.SOLUTION: A minimum display unit 31 which constitutes a pattern 21 that can be displayed by a light guide plate 2 of a display device has a first prism 22a and a second prism 22b, and reflective surfaces 23 of the first and second prisms have a curved shape that is convex to an incidence surface 2a of the light guide plate 2. The first and second prisms are arranged such that a ratio of light amounts of light emitted from first and second light sources that have mutually-different luminous colors, incident on the light guide plate 2 and reflected by the reflective surface of the first prism 22a toward a prescribed direction becomes the first ratio and the ratio of the light amounts of the light emitted from second and third light sources that have mutually-different luminous colors, incident on the light guide plate 2 and reflected by the reflective surface of the second prism 22b toward the prescribed direction becomes the second ratio. The first ratio and the second ratio are set so that the minimum display unit is displayed in a predetermined display color.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD

[0001] The present invention relates to a display device capable of displaying a pattern using a light guide plate, and a gaming machine having such a display device. BACKGROUND ART

[0002] In display devices that display patterns using a light guide plate, a technology has been proposed in which the color of the displayed pattern is a mixture of emission colors from a plurality of light sources (see, for example, Patent Document 1).

[0003] For example, the display device disclosed in Patent Document 1 includes a light guide plate capable of displaying at least one pattern, and a plurality of light sources arranged side by side along the light incident surface of the light guide plate. On one surface of the light guide plate, there are provided a plurality of prisms each having a reflective surface that is arranged along the pattern and reflects light emitted from any of the plurality of light sources and entering the light guide plate from the light incident surface so as to exit from the other light exit surface of the light guide plate. A first light source and a second light source among the plurality of light sources emit light of mutually different colors. Further, the reflective surface of each individual prism arranged along a specific sub-pattern in the pattern is formed to have a curved surface shape that is convex toward the light incident surface of the light guide plate, and is arranged to reflect light from each of the first light source and the second light source toward the same direction on the other surface side of the light guide plate. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0004] PATENT DOCUMENT 1 Japanese Unexamined Patent Application Publication No. 2021-144129 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] In the above technology, the display device can make the sub-pattern appear to glow with colors obtained by additive color mixing of light from the first light source and light from the second light source. However, to enhance the observer's interest, it is desirable to be able to represent the pattern with a wider variety of color combinations.

[0006] Therefore, the present invention aims to provide a display device that can represent the displayed pattern with a wider variety of color combinations. [Means for solving the problem]

[0007] One embodiment of the present invention is provided: a display device. This display device comprises a light guide plate formed in a sheet shape from a transparent material, capable of displaying at least one pattern, and having an incident surface formed on one of its sides, and a plurality of light sources facing the incident surface of the light guide plate and arranged along the longitudinal direction of the incident surface. The plurality of light sources include at least a first light source, a second light source, and a third light source, each having a different emission color. The light guide plate has a plurality of prisms formed on one of its surfaces and arranged along the pattern, which cause light emitted from any of the plurality of light sources and incident into the light guide plate from the incident surface to be emitted from the other surface of the light guide plate. The pattern is composed of a combination of a plurality of minimum display units, and at least one of the plurality of minimum display units has a first prism and a second prism from the plurality of prisms, and each of the first prism and the second prism has a reflective surface formed along one surface of the light guide plate to be a curved shape convex with respect to the incident surface. The first prism is positioned such that the ratio of the first light intensity of the first light emitted from the first light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate, and traveling in a predetermined direction, to the second light intensity of the second light emitted from the second light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate, and traveling in a predetermined direction, is the first ratio. The second prism is positioned such that the ratio of the third light intensity of the third light emitted from the second light source, reflected by the reflective surface of the second prism and emitted from the other surface of the light guide plate, and traveling in a predetermined direction, to the fourth light intensity of the fourth light emitted from the third light source, reflected by the reflective surface of the second prism and emitted from the other surface of the light guide plate, and traveling in a predetermined direction, is the second ratio. The first ratio and the second ratio are set so that the smallest display unit is displayed in a predetermined display color. By having such a configuration, this display device can represent the displayed pattern with a wider variety of color combinations.

[0008] In this display device, it is preferable that the first prism is positioned such that the normal direction of the center of the reflective surface of the first prism on one surface of the light guide plate points closer to the first light source than the second light source as the first ratio of the first light quantity to the second light quantity increases, and the second prism is positioned such that the normal direction of the center of the reflective surface of the second prism on one surface of the light guide plate points closer to the third light source than the second light source as the second ratio of the fourth light quantity to the third light quantity increases. This allows the display device to appropriately set the color of light directed from the smallest display unit in a predetermined direction to the display color of that smallest display unit.

[0009] In this case, if the color component corresponding to the emission color of the first light source included in the predetermined display color is greater than the color component corresponding to the emission color of the third light source included in the predetermined display color, it is even more preferable that the first prism and the second prism are formed such that the reflective surface of the first prism is larger than the reflective surface of the second prism. This allows the display device to represent differences in the size of individual color components contained in the display color of the smallest display unit, thus enabling more flexible setting of the display color of the smallest display unit.

[0010] Furthermore, it is preferable that the first and second prisms are formed such that, among the multiple minimum display units, the curvature of the reflective surface of the first prism and the reflective surface of the second prism included in the minimum display unit becomes smaller the further the minimum display unit is from the incident surface of the light guide plate. As a result, for each smallest display unit, regardless of the distance from each light source, each prism contained within that smallest display unit can reflect light from the two corresponding light sources in the same predetermined direction.

[0011] According to another embodiment of the present invention, a display device is provided comprising a light guide plate formed in a sheet shape from a transparent material, capable of displaying at least one pattern, and having an incident surface formed on one of its sides, and a plurality of light sources facing the incident surface of the light guide plate and arranged along the longitudinal direction of the incident surface. In this display device, the plurality of light sources include at least a first light source, a second light source, and a third light source, each having a different emission color. The light guide plate has a plurality of prisms formed on one of its surfaces and arranged along the pattern, which cause light emitted from any of the plurality of light sources and incident into the light guide plate from the incident surface to be emitted from the other surface of the light guide plate. The pattern is composed of a combination of a plurality of minimum display units, and at least one of the plurality of minimum display units has a first prism and a second prism from the plurality of prisms. The first prism has a reflective surface formed in a curved shape convex to the incident surface along one surface of the light guide plate, and the first prism is positioned such that the ratio of the first amount of light of the first light emitted from the first light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate and traveling in a predetermined direction, to the second amount of light of the second light emitted from the second light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate and traveling in a predetermined direction is the first ratio. The second prism has a reflective surface formed in a planar shape along one surface, and the second prism is positioned such that light emitted from the third light source, reflected by the reflective surface of the second prism and emitted from the other surface of the light guide plate and traveling in a predetermined direction. The first ratio, the size of the reflective surface of the first prism, and the size of the reflective surface of the second prism are set so that the smallest display unit is displayed in a predetermined display color. By having such a configuration, this display device can represent the displayed pattern with a wider variety of color combinations.

[0012] According to yet another embodiment of the present invention, a gaming machine is provided having a gaming machine body and a display device provided on the side of the gaming machine body facing the player. In this gaming machine, the display device has a light guide plate formed in a sheet shape from a transparent material, capable of displaying at least one pattern, and having an incident surface formed on one of its sides, and a plurality of light sources facing the incident surface of the light guide plate and arranged along the longitudinal direction of the incident surface. The plurality of light sources include at least a first light source, a second light source, and a third light source, each having a different emission color. The light guide plate has a plurality of prisms formed on one side facing the gaming machine body and arranged along the pattern, which cause light emitted from any of the plurality of light sources and incident into the light guide plate from the incident surface to be emitted from the other side of the light guide plate. The pattern is composed of a combination of multiple minimum display units, and at least one of the multiple minimum display units has a first prism and a second prism from a plurality of prisms, and each of the first prism and the second prism has a reflective surface formed to be a curved shape that is convex with respect to the incident surface along one surface of the light guide plate. The first prism is positioned such that the ratio of the amount of light from the first light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate, and traveling in a predetermined direction, to the amount of light from the second light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate, and traveling in a predetermined direction, is the first ratio. The second prism is positioned such that the ratio of the amount of light from the second light source, reflected by the reflective surface of the second prism and emitted from the other surface of the light guide plate, and traveling in a predetermined direction, to the amount of light from the third light source, reflected by the reflective surface of the second prism and emitted from the other surface of the light guide plate, and traveling in a predetermined direction, is the second ratio. The first ratio and the second ratio are set so that the smallest display unit is displayed in a predetermined display color. By having such a configuration, this gaming machine can display patterns using a wider variety of color combinations. [Brief explanation of the drawing]

[0013] [Figure 1]This is a schematic configuration diagram of a display device according to one embodiment of the present invention. [Figure 2] This is a schematic front view of the light guide plate of the display device. [Figure 3] This is a schematic side cross-sectional view of the light guide plate along the line indicated by arrow AA' in Figure 2. [Figure 4] This is a schematic diagram showing the configuration of a single minimum display unit, with the light guide plate viewed from the front. [Figure 5] (a) and (b) are schematic perspective and cross-sectional views showing the shape of the prism. [Figure 6] (a) and (b) are schematic perspective views and schematic cross-sectional views showing the shape of a prism due to a modification. [Figure 7] This is a schematic perspective view of a pinball game machine having a display device according to an embodiment or modification. [Modes for carrying out the invention]

[0014] The following describes a display device according to an embodiment of the present invention with reference to the figures. This display device has a light guide plate formed in sheet form from a material transparent to light emitted from multiple light sources, with the front surface of the light guide plate formed as the emission surface facing the observer. Furthermore, one of the surrounding sides of the light guide plate that encloses the emission surface is formed as the incidence surface facing the multiple light sources. On the other surface of the light guide plate facing the emission surface (hereinafter referred to as the back surface), multiple prisms are formed that reflect light emitted from the multiple light sources and incident into the light guide plate toward the emission surface. Each of the multiple prisms is arranged along at least one pattern to be displayed by the display device. In this display device, the multiple light sources include a first light source, a second light source, and a third light source, each with a different emission color. The pattern is composed of a combination of minimum display units, which are the smallest units of color control. At least one of the smallest display units includes two prisms, each of which has a reflective surface that is convex to the incident surface when viewed from the normal direction to the back of the light guide plate, i.e., along the back. The reflective surface of one of the two prisms is directed in a direction such that the amount of light from a first light source, reflected by its reflective surface and directed toward a predetermined direction on the exit surface, and the amount of light from a second light source, reflected by its reflective surface and directed toward a predetermined direction on the exit surface, are in a first ratio. The reflective surface of the other of the two prisms is directed in a direction such that the amount of light from a second light source, reflected by its reflective surface and directed toward a predetermined direction on the exit surface, and the amount of light from a fourth light source, reflected by its reflective surface and directed toward a predetermined direction on the exit surface, are in a second ratio. The first and second ratios are set according to the color (hereinafter sometimes referred to as the display color) that the smallest display unit formed by the two prisms is visible to the observer.

[0015] Figure 1 is a schematic diagram of a display device according to one embodiment of the present invention. The display device 1 includes a light guide plate 2, a plurality of light sources 3-1 to 3-n, a storage unit 4, and a control unit 5.

[0016] The light guide plate 2 is a member formed in a transparent sheet shape for light emitted from each of the plurality of light sources 3-1 to 3-n. The light guide plate 2 is formed, for example, by molding a resin transparent to visible light, such as polymethyl methacrylate (PMMA), polycarbonate, or cycloolefin polymer. The light guide plate 2 is provided with a pattern 21 that can be displayed by turning on at least any one of the plurality of light sources 3-1 to 3-n. However, the number of displayable patterns provided on the light guide plate 2 is not limited to one, and the design of the pattern is not limited to the example shown in FIG. 1. While any of the plurality of light sources 3-1 to 3-n is lit, the light guide plate 2 propagates the light from the lit light source therein, and reflects the light toward the observer located on the front side of the light guide plate 2 by a plurality of prisms (details will be described later) arranged to form the pattern 21 formed on the back side. This allows the observer to visually recognize the light-emitting pattern 21. The details of the light guide plate 2 will be described later.

[0017] Each of the plurality of light sources 3-1 to 3-n has at least one light-emitting element that emits visible light. In the present embodiment, the plurality of light sources 3-1 to 3-n are arranged in a line along the longitudinal direction of the light incident surface 2a, which is one of the side surfaces of the light guide plate 2. Note that the distance between the two light sources for each pair of two adjacent light sources may be equal, or may be different from each other.

[0018] Each of the light sources 3-1 to 3-n is turned on or off in response to a control signal from the control unit 5. While the control unit 5 lights each of the light sources 3-1 to 3-n, the light emitted from each of the light sources 3-1 to 3-n enters the light guide plate 2 via the light incident surface 2a. The incident light propagates through the light guide plate 2 while being totally reflected, then is reflected by the plurality of prisms forming the pattern 21 provided on the back surface of the light guide plate 2, and exits from the light exit surface on the front side.

[0019] Each light source 3-1 to 3-n has a light-emitting element, such as a light-emitting diode (LED), that emits light in the light source's color. Note that each light source 3-1 to 3-n may be a light source with a variable light-emitting color. For example, each light source 3-1 to 3-n may have a red LED, a green LED, and a blue LED, respectively. In this case, the light-emitting color of each light source 3-1 to 3-n will be a color corresponding to the combination of light-emitting intensities of the red, green, and blue LEDs in that light source.

[0020] In this embodiment, the plurality of light sources 3-1 to 3-n include at least one pair of first light sources 3-r, second light source 3-g, and third light source 3-b, each having a different emission color (where r, g, b ∈ {1, 2, ..., n} and r ≠ g ≠ b). For example, the emission color of the first light source 3-r is red, the emission color of the second light source 3-g is green, and the emission color of the third light source 3-b is blue. However, the combination of emission colors of the first light source 3-r, second light source 3-g, and third light source 3-b is not limited to the above example; the combination of emission colors of the first light source 3-r, second light source 3-g, and third light source 3-b can be determined according to the colors of each part of the displayed pattern 21.

[0021] Furthermore, the multiple light sources 3-1 to 3-n may include four or more light sources with different emission colors. In this case, a light source having an emission color that is the complementary color of the emission color of the first light source 3-r or the second light source 3-g may be placed between the first light source 3-r and the second light source 3-g. Similarly, a light source having an emission color that is the complementary color of the emission color of the second light source 3-g or the third light source 3-b may be placed between the second light source 3-g and the third light source 3-b. This makes it easier to adjust the colors of each part of pattern 21. Furthermore, the number of light sources provided for each emission color may differ. For example, the number of light sources with a white or red emission color may be greater than the number of light sources with a green or blue emission color. This makes it easier to adjust the display color of any smallest display unit to skin tone. Conversely, the number of light sources with a green or blue emission color may be greater than the number of light sources with a red or white emission color. In this case, it becomes easy to adjust the display color of any of the smallest display units to light blue or yellow-green.

[0022] The memory unit 4 has, for example, a volatile or non-volatile memory circuit. The memory unit 4 stores lighting control information, such as the timing of turning on and off each light source 3-1 to 3-n.

[0023] The control unit 5 includes, for example, a processor and a drive circuit for driving each of the light sources 3-1 to 3-n. The control unit 5 controls the lighting and extinguishing of each of the light sources 3-1 to 3-n according to the lighting control information.

[0024] The control unit 5 illuminates at least one of the light sources 3-1 to 3-n when, for example, the pattern 21 is visible to an observer positioned on the front side of the light guide plate 2, i.e., facing the light-emitting surface of the light guide plate 2. Conversely, when the pattern 21 is not visible to the observer, the control unit 5 turns off the light sources 3-1 to 3-n. The control unit 5 may also sequentially change the combination of light sources that are illuminated from among the light sources 3-1 to 3-n according to the illumination control information in order to dynamically change the color of the pattern 21 visible to the observer. Furthermore, if the light sources 3-1 to 3-n are composed of light sources with variable emission color, the control unit 5 may sequentially change the emission color of each light source 3-1 to 3-n in order to dynamically change the color of the pattern 21 visible to the observer. Note that when the pattern 21 is to be visible at all times, the control unit 5 may keep the light sources 3-1 to 3-n illuminated at all times while the display device 1 is operating, without referring to the illumination control information.

[0025] The following describes the details of the light guide plate 2.

[0026] Figure 2 is a schematic front view of the light guide plate 2. Figure 3 is a schematic side cross-sectional view of the light guide plate 2 along the line indicated by arrow AA' in Figure 2. As shown in Figures 2 and 3, one side of the light guide plate 2 is formed as the incident surface 2a facing each of the light sources 3-1 to 3-n. As described above, the light emitted from each of the light sources 3-1 to 3-n enters the interior of the light guide plate 2 from the incident surface 2a. The light from each of the light sources 3-1 to 3-n propagates inside the light guide plate 2, undergoes total internal reflection by each of the multiple prisms 22 formed in a groove shape on the back surface 2b of the light guide plate 2, and then exits from the exit surface 2c, which is located on the front side of the light guide plate 2 and faces the back surface 2b. Since the multiple prisms 22 are arranged along the pattern 21, the pattern 21 will appear to glow to an observer positioned on the front side of the exit surface 2c.

[0027] In this embodiment, the pattern 21 is represented by a combination of multiple minimum display units 31. That is, each minimum display unit 31 corresponds to a pixel in an image, and the display device 1 controls the color visible to the observer for each minimum display unit 31. Each minimum display unit 31 has a size that makes it impossible to distinguish between individual minimum display units 31 when the observer views the pattern 21 from a predetermined distance (e.g., several tens of centimeters) away from the light guide plate 2, for example, a length of several micrometers to several hundred micrometers in the longitudinal direction.

[0028] Figure 4 is a schematic diagram of the light guide plate 2 viewed from the front, showing the configuration of one minimum display unit. In the example shown in Figure 4, the first light source 3-r emits red light, the second light source 3-g emits green light, and the third light source 3-b emits blue light. The first light source 3-r, the second light source 3-g, and the third light source 3-b are arranged at equal intervals from left to right along the longitudinal direction of the incident surface 2a of the light guide plate 2.

[0029] In this embodiment, one minimum display unit 400 includes two prisms 22a and 22b. Prism 22a is an example of a first prism, and prism 22b is an example of a second prism. The two prisms 22a and 22b constituting the minimum display unit 400 each have a reflective surface 23 that is an arc-shaped curved surface that is convex with respect to the incident surface 2a when viewed from the direction normal to the back surface 2b, that is, on the surface along the back surface 2b. Therefore, the reflective surface 23 is capable of reflecting light from two of the first light source 3-r, the second light source 3-g, and the third light source 3-b toward the same predetermined direction toward the exit surface 2c. The predetermined direction can be, for example, the direction normal to the exit surface 2c. That is, the reflective surfaces 23 of the two prisms 22a and 22b are formed such that, on the surface along the back surface 2b, one of the positions of the reflective surface 23 faces directly toward each of the two light sources corresponding to that prism.

[0030] With the formation of these two prisms 22a and 22b, in the example shown in Figure 4, the reflective surface 23 of the prism 22a positioned on the left can reflect light from the first light source 3-r positioned on the far left and light from the second light source 3-g positioned in the center toward a predetermined direction toward the emission surface 2c. On the other hand, the reflective surface 23 of the prism 22b positioned on the right can reflect light from the third light source 3-b positioned on the far right and light from the second light source 3-g positioned in the center toward a predetermined direction toward the emission surface 2c. Therefore, for the smallest display unit 400, light from the first light source 3-r, the second light source 3-g, and the third light source 3-b will reach the observer positioned on the front side of the emission surface 2c. Therefore, the smallest display unit of 400 is represented by a color obtained by additively mixing red light from the first light source 3-r, green light from the second light source 3-g, and blue light from the third light source 3-b.

[0031] Furthermore, it is preferable that each prism is formed such that the curvature of the reflective surface of each prism included in the minimum display unit decreases as the minimum display unit moves further away from each light source. In the example shown in Figure 4, each prism is formed such that the curvature of the reflective surfaces of prisms 22c and 22d included in the minimum display unit 401, which is further from each light source than the minimum display unit 400, is smaller than the curvature of the reflective surfaces of prisms 22a and 22b included in the minimum display unit 400. As a result, for each minimum display unit, regardless of the distance from each light source, each prism included in the minimum display unit can reflect light from the two corresponding light sources toward the same predetermined direction on the emission surface 2c side.

[0032] Furthermore, with respect to the center of the reflective surface 23 of the prism 22a on the surface along the back surface 2b of the light guide plate 2, that is, when viewed from the direction normal to the back surface 2b, the normal direction to that center (hereinafter simply referred to as the normal direction of the prism 22a) is determined according to the display color of the minimum display unit 400. That is, the higher the ratio of the red component to the green component in the display color of the minimum display unit 400, the more the prism 22a is positioned so that the normal direction of the prism 22a points toward the first light source 3-r. The closer the light source is to the center of the reflective surface 23 of the prism 22a (that is, the closer the position on the reflective surface 23 where the light source is located in the normal direction is to the center of the reflective surface 23), the greater the amount of light emitted from that light source, reflected by the reflective surface 23, and directed toward the predetermined direction. Therefore, by positioning the prism 22 as described above, the ratio of the red component to the green component is set to the ratio corresponding to the display color of the minimum display unit 400.

[0033] More specifically, the light from the second light source 3-g, positioned in the center, can be reflected by both prisms 22a and 22b in the same direction toward the emission surface 2c. Therefore, of the red, green, and blue components included in the minimum display unit 400, half of the light amount corresponding to the green component, which is the emitted color of the second light source 3-g positioned in the center, is represented by the reflection of light from the second light source 3-g by prism 22a, and the remaining half of the light amount corresponding to the reflection of light from the second light source 3-g by prism 22b is represented by the reflection of light from the second light source 3-g by prism 22b. Here, p1 is the intersection point of the line m1 connecting the first light source 3-r and the second light source 3-g and the normal direction n1 of prism 22a. At this time, the prism 22a is positioned such that the ratio of the amount of light of the red component R (first light quantity) to the amount of light of half the amount of light of the green component (second light quantity) Mh (R / Mh) of the minimum display unit of 400 is approximately equal to the ratio of the distance d1 between the intersection point p1 and the first light source 3-r to the distance d2 between the intersection point p1 and the second light source 3-g (d2 / d1). Note that the ratio (R / Mh) is an example of the first ratio.

[0034] Similarly, with respect to the center of the reflective surface 23 of the prism 22b when viewed from the normal direction of the back surface 2b, the normal direction to that center (hereinafter, the normal direction of the prism 22b) is determined according to the display color of the minimum display unit 400. That is, the higher the ratio of the blue component to the green component in the display color of the minimum display unit 400, the more the prism 22b is positioned so that its normal direction points towards the third light source 3-b. In other words, if p2 is the intersection point of the line m2 connecting the second light source 3-g and the third light source 3-b with the normal direction n2 of the prism 22b, then the prism 22b is positioned such that the ratio of the amount of light of the blue component B (fourth light quantity) to the amount of light of half the amount of light of the green component (third light quantity) Mh (B / Mh) for a minimum display unit of 400 is approximately equal to the ratio of the distance d4 between the intersection point p2 and the third light source 3-b to the distance d3 between the intersection point p2 and the second light source 3-g (d3 / d4). Note that the ratio (B / Mh) is an example of the second ratio.

[0035] For example, if the display color with a minimum display unit of 400 is represented as (R=50, G=100, B=200), the prism 22a is positioned such that its normal direction n1 points to the midpoint between the first light source 3-r and the second light source 3-g. Similarly, the prism 22b is positioned such that its normal direction n2 points to a position that divides the distance between the second light source 3-g and the third light source 3-b in a 4:1 ratio.

[0036] Furthermore, in this example, if the display color of the smallest display unit 400 does not include a red component, prism 22a may be omitted. Alternatively, prism 22a may also be positioned to face the same direction as prism 22b. Similarly, if the display color of the smallest display unit 400 does not include a blue component, prism 22b may be omitted. Alternatively, prism 22b may also be positioned to face the same direction as prism 22a.

[0037] Furthermore, prisms 22a and 22b may be configured such that the reflective surfaces of prisms 22a and 22b increase as the luminance of the minimum display unit 400 increases. Additionally, prism 22a may be configured such that the reflective surface of prism 22a increases as the sum of the red and green components included in the display color of the minimum display unit 400 increases. Similarly, prism 22b may be configured such that the reflective surface of prism 22b increases as the sum of the green and blue components included in the display color of the minimum display unit 400 increases. Moreover, if the color component corresponding to the emission color of the first light source 3-r included in the display color of the minimum display unit 400 is greater than the color component corresponding to the emission color of the third light source 3-b included in that display color, prisms 22a and 22b may be formed such that the reflective surface of prism 22a is larger than the reflective surface of prism 22b. Conversely, if the color component corresponding to the emission color of the third light source 3-b included in the display color of the minimum display unit 400 is larger than the color component corresponding to the emission color of the first light source 3-r included in that display color, then prisms 22a and 22b may be formed such that the reflective surface of prism 22b is larger than the reflective surface of prism 22a. In this way, by setting the size of the reflective surface of each prism according to the corresponding color component or luminance in the display color of the minimum display unit 400, it becomes possible to express the differences in the size of individual color components included in the display color of the minimum display unit 400. Therefore, it becomes possible to set the display color of the minimum display unit 400 more flexibly.

[0038] Figure 5(a) is a schematic perspective view of the prism 22, and Figure 5(b) is a schematic side cross-sectional view of the prism 22 along the line indicated by arrow BB' in Figure 5(a).

[0039] As shown in Figures 5(a) and 5(b), the prism 22 is formed as a groove on the back surface 2b of the light guide plate, having a predetermined length and a shape that is wider in the center and narrows towards the edges. Of the two inclined surfaces of the prism 22, the inclined surface facing the incident surface 2a of the light guide plate 2, that is, the inclined surface facing each of the light sources 3-1 to 3-n, is formed as a reflecting surface 23 that reflects the light from the corresponding light source among each of the light sources 3-1 to 3-n toward the exit surface 2c. Furthermore, the prism 22 is formed such that the cross-sectional shape of the surface perpendicular to the back surface 2b and the reflecting surface 23 is approximately triangular. For example, the reflecting surface 23 is positioned at an angle, for example, 40° to 50° with respect to the back surface 2b, that totally reflects the light emitted from the corresponding light source among each of the light sources 3-1 to 3-n that is incident on the light guide plate 2 and directs it toward the exit surface 2c.

[0040] Figures 6(a) and 6(b) are schematic perspective and cross-sectional views, respectively, showing the shape of a modified prism. Similar to prism 22, the prism 24 in this modified form is formed such that the reflective surface 25, which is the slope facing each light source 3-1 to 3-n, is a curved surface that is convex with respect to the incident surface 2a along the back surface 2b. On the other hand, prism 24 differs from prism 22 in that the slope not facing each light source 3-1 to 3-3 is formed concentrically with respect to the reflective surface 25 along the back surface 2b. Note that prisms 22 and prism 24 may be formed such that the cross-sectional shape of the reflective surface on the surface perpendicular to the back surface 2b and the reflective surface is convex with respect to the exit surface 2c.

[0041] As described above, in this display device, at least one of the smallest display units that make up the pattern displayed on the light guide plate includes two prisms, and each of the two prisms has a reflective surface that is curved and convex with respect to the incident surface, along the back surface of the light guide plate. The reflective surface of one of the two prisms is oriented in a direction such that the amount of light from a first light source, reflected by its reflective surface and directed toward a predetermined direction on the exit surface, and the amount of light from a second light source, reflected by its reflective surface and directed toward a predetermined direction on the exit surface, are in a first ratio. The reflective surface of the other of the two prisms is oriented in a direction such that the amount of light from a second light source, reflected by its reflective surface and directed toward a predetermined direction on the exit surface, and the amount of light from a fourth light source, reflected by its reflective surface and directed toward a predetermined direction on the exit surface, are in a second ratio. The first and second ratios are set according to the color of the smallest display unit displayed by the two prisms. This allows for the setting of various display colors for each smallest display unit of the pattern, enabling this display device to represent the displayed pattern with a wider variety of color combinations.

[0042] In a modified version, the reflective surface of one of the two prisms constituting the minimum display unit may be formed in a planar shape along the back surface 2b of the light guide plate 2, that is, when viewed from the direction normal to the back surface 2b, and may be formed to face directly toward one of the corresponding first light source, second light source, and third light source. In this case as well, by setting the orientation of the reflective surface of the other prism and the size of the reflective surface of each prism according to the display color of the minimum display unit, the display device can arbitrarily set the display color of the minimum display unit.

[0043] In other modifications, two or more of the first light source 3-r, the second light source 3-g, and the third light source 3-b may be arranged side by side along the longitudinal direction of the incident surface 2a. This makes it possible to widen the viewing angle in which the display color of each smallest display unit visible to the observer does not change along the longitudinal direction of the incident surface 2a. Furthermore, the light sources may be arranged such that the number of any one of the first light source 3-r, the second light source 3-g, and the third light source 3-b is greater than the number of the other light sources.

[0044] In further modifications, the first light source 3-r, the second light source 3-g, and the third light source 3-b may each be composed of a light source with a variable emission color. In this case, the control unit 5 may control the emission color of each light source so that the pattern 21 can be switched between color and monochrome display. In this case, when the pattern 21 is displayed in color, the control unit 5 controls each light source so that each light source emits light with a different emission color from the others, as in the above embodiment. On the other hand, when the pattern 21 is displayed in monochrome, the control unit 5 controls each light source so that the ratio of red, green, and blue components in the emission color of each light source is approximately 3:6:1. As a result, the pattern 21 is monochromeized in terms of brightness, so that the observer can see the monochromeized pattern.

[0045] The display device according to the above embodiment or modification may be mounted on a game machine such as a pinball game machine or a slot machine. Figure 7 is a schematic perspective view of a pinball game machine having a display device according to the above embodiment or modified example, as seen from the player's side. As shown in Figure 7, the pinball game machine 100 has a game board 101 which is the game machine body, which is provided in most of the area from the top to the center, a ball receiving section 102 disposed below the game board 101, an operating section 103 with a handle, a liquid crystal display 104 provided approximately in the center of the game board 101, and a display device 105 positioned in front of the liquid crystal display 104.

[0046] The pinball game machine 100 also has a mechanism 106 positioned on the front of the game board 101, either below the game board 101 or around the display device 105, for the purpose of enhancing the game's presentation. Rails 107 are also provided on the sides of the game board 101. In addition, the game board 101 is equipped with numerous obstacle pins (not shown) and at least one prize-winning device 108.

[0047] The operation unit 103 launches game balls with a predetermined force from a launching device (not shown) according to the amount of rotation of the handle by the player. The launched game balls move upward along the rail 107 and fall between a number of obstacle pins. When a sensor (not shown) detects that a game ball has entered any of the prize-winning devices 108, the main control circuit (not shown) located on the back of the game board 101 dispenses a predetermined number of game balls corresponding to the prize-winning device 108 into the ball receiving unit 102 via a ball dispensing device (not shown). Furthermore, the main control circuit drives the liquid crystal display 104 and the display device 105 via a performance CPU (not shown) located on the back of the game board 101. The performance CPU then transmits control signals, including lighting control information according to the state of the game, to the display device 105.

[0048] The display device 105 is an example of a display device according to the above embodiment or a modified version, and is attached to the game board 101 such that the light-emitting surface of the light guide plate faces the player. The control unit of the display device 105 lights up each light source according to the lighting control information included in the control signal from the performance CPU, so that the player can see the pattern along with the image displayed on the liquid crystal display 104. Alternatively, the control unit may turn off all light sources according to the lighting control information so that the player can observe only the image displayed on the liquid crystal display 104 via the light guide plate.

[0049] Thus, those skilled in the art can make various modifications within the scope of the present invention to suit the implemented form. [Explanation of symbols]

[0050] 1 Display device 2 Light guide plate 2a Incidence plane 2b Back 2c Output surface 3-1~3-n light source 3-r First light source 3-g Second light source 3-b The third light source 22, 22a, 22b, 24 prisms 23, 25 reflective surface 21 patterns 31, 400, 401 minimum display units 4 Storage section 5. Control Unit 100 Pinball Game Machines 101 Game Board 102 Ball receiving section 103 Operation section 104 LCD display 105 Display device 106 Special Features 107 Rails 108 Prize-winning device

Claims

1. A light guide plate formed in a sheet shape from a transparent material, capable of displaying at least one pattern, and having an incident surface formed on one of its sides, It has a plurality of light sources that are facing the incident surface and arranged along the longitudinal direction of the incident surface, The plurality of light sources include at least a first light source, a second light source, and a third light source, each having a different emission color. The light guide plate has a plurality of prisms formed on one surface of the light guide plate and arranged along the pattern, which cause light emitted from any of the plurality of light sources and incident into the light guide plate from the incident surface to be emitted from the other surface of the light guide plate. The pattern is composed of a combination of multiple minimum display units, and at least one of the multiple minimum display units has a first prism and a second prism among the multiple prisms. Each of the first prism and the second prism has a reflective surface formed to be a curved shape that is convex with respect to the incident surface along one of its surfaces. The first prism is arranged such that the ratio of the first amount of light of the first light emitted from the first light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate, and directed in a predetermined direction, to the second amount of light of the second light emitted from the second light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate, and directed in the predetermined direction, is a first ratio. The second prism is arranged such that the ratio of the third light quantity of the third light emitted from the second light source, reflected by the reflective surface of the second prism and emitted from the other surface of the light guide plate, and directed in the predetermined direction, to the fourth light quantity of the fourth light emitted from the third light source, reflected by the reflective surface of the second prism and emitted from the other surface of the light guide plate, and directed in the predetermined direction, is the second ratio. The first ratio and the second ratio are set so that the minimum display unit is displayed in a predetermined display color. A display device in which, as the first ratio of the first light quantity to the second light quantity increases, the first prism is positioned such that the normal direction of the center of the reflective surface of the first prism on one surface of the light guide plate points closer to the first light source than to the second light source, and as the second ratio of the fourth light quantity to the third light quantity increases, the second prism is positioned such that the normal direction of the center of the reflective surface of the second prism on one surface of the light guide plate points closer to the third light source than to the second light source.

2. The display device according to claim 1, wherein if the color component corresponding to the emission color of the first light source, included in the predetermined display color, is greater than the color component corresponding to the emission color of the third light source, included in the predetermined display color, the first prism and the second prism are formed such that the reflective surface of the first prism is greater than the reflective surface of the second prism.

3. The display device according to claim 1, wherein, among the plurality of minimum display units, the first prism and the second prism are formed such that the curvature of the reflective surface of the first prism and the reflective surface of the second prism included in the minimum display unit becomes smaller the further the minimum display unit is from the incident surface.

4. A light guide plate formed in a sheet shape from a transparent material, capable of displaying at least one pattern, and having an incident surface formed on one of its sides, It has a plurality of light sources that are facing the incident surface and arranged along the longitudinal direction of the incident surface, The plurality of light sources include at least a first light source, a second light source, and a third light source, each having a different emission color. The light guide plate has a plurality of prisms formed on one surface of the light guide plate and arranged along the pattern, which cause light emitted from any of the plurality of light sources and incident into the light guide plate from the incident surface to be emitted from the other surface of the light guide plate. The pattern is composed of a combination of multiple minimum display units, and at least one of the multiple minimum display units has a first prism and a second prism among the multiple prisms. The first prism has a reflective surface formed to be a curved shape convex with respect to the incident surface along one of its surfaces, and the first prism is arranged such that the ratio of the first amount of light of the first light emitted from the first light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate and traveling in a predetermined direction, to the second amount of light of the second light emitted from the second light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate and traveling in the predetermined direction, is a first ratio. The second prism has a reflective surface formed planarly along one of its surfaces, and the second prism is positioned such that light emitted from the third light source is reflected by the reflective surface of the second prism and exits from the other surface of the light guide plate, and is directed in the predetermined direction. The first ratio, the size of the reflective surface of the first prism, and the size of the reflective surface of the second prism are set such that the minimum display unit is displayed in a predetermined display color. A display device in which, as the first ratio of the first light quantity to the second light quantity increases, the first prism is arranged such that the normal direction of the center of the reflective surface of the first prism on one surface of the light guide plate points closer to the first light source than to the second light source.

5. The gaming machine itself, The gaming machine has a display device provided on the side of the gaming machine body facing the player, The aforementioned display device is A light guide plate formed in a sheet shape from a transparent material, capable of displaying at least one pattern, and having an incident surface formed on one of its sides, It has a plurality of light sources that are facing the incident surface and arranged along the longitudinal direction of the incident surface, The plurality of light sources include at least a first light source, a second light source, and a third light source, each having a different emission color. The light guide plate has a plurality of prisms formed on one side of the light guide plate facing the gaming machine body, arranged along the pattern, which cause light emitted from any of the plurality of light sources and incident into the light guide plate from the incident surface to be emitted from the other side of the light guide plate. The pattern is composed of a combination of multiple minimum display units, and at least one of the multiple minimum display units has a first prism and a second prism among the multiple prisms. Each of the first prism and the second prism has a reflective surface formed to be a curved shape that is convex with respect to the incident surface along one of its surfaces. The first prism is arranged such that the ratio of the first amount of light of the first light emitted from the first light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate, and directed in a predetermined direction, to the second amount of light of the second light emitted from the second light source, reflected by the reflective surface of the first prism and emitted from the other surface of the light guide plate, and directed in the predetermined direction, is a first ratio. The second prism is arranged such that the ratio of the third light quantity of the third light emitted from the second light source, reflected by the reflective surface of the second prism and emitted from the other surface of the light guide plate, and directed in the predetermined direction, to the fourth light quantity of the fourth light emitted from the third light source, reflected by the reflective surface of the second prism and emitted from the other surface of the light guide plate, and directed in the predetermined direction, is the second ratio. The first ratio and the second ratio are set so that the minimum display unit is displayed in a predetermined display color. The larger the first ratio of the first light quantity to the second light quantity, the more the first prism is positioned such that the normal direction of the center of the reflective surface of the first prism on one surface of the light guide plate points closer to the first light source than to the second light source, and the larger the second ratio of the fourth light quantity to the third light quantity, the more the second prism is positioned such that the normal direction of the center of the reflective surface of the second prism on one surface of the light guide plate points closer to the third light source than to the second light source. Gaming machine.

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