JP2012002968A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of causing a display to emit light efficiently and uniformly with a small light source.SOLUTION: A lens component 20 is disposed between a display 4 and an LED 10. The lens component 20 is integrally configured by a convex lens 21, an inner layer 22, a concave lens 23 and a surface layer 24. The convex lens 21 is disposed at the LED 10 side and the concave lens 23 is disposed at the display 4 side. The light from the LED 10 is firstly made incident on a convex lens 21 and then is condensed by the convex lens 21. The condensed light passes through the inner layer 22 and then is made incident on a concave lens 23 and diffused by the concave lens 23. The diffused light is irradiated into the display 4 through the surface layer 24. Accordingly, the convex lens 21 can prevent the light from leaking around and irradiate light in a wide range by concave lens 23, thereby enabling causing the display 4 to emit light efficiently and uniformly.

Description

  The present invention relates to a display device including a light source and a display unit that performs light-emitting display when irradiated with light emitted from the light source.

  2. Description of the Related Art Conventionally, some machine products such as copying machines have a function of notifying a user of a machine state by turning on or blinking a light source such as an LED or a light bulb. A display device as a function of this type includes a display unit for displaying the state of the machine, and the display unit emits light, that is, displays the state of the machine, by irradiating light from the light source to the display unit. Is made.

  Incidentally, in the display device, it is important to improve the visibility when the display unit emits light. In this regard, conventionally, in order to make the light emission of the display unit uniform and improve the visibility, the surface of the display unit is embossed, or the resin cover provided on the display unit is made translucent, A method of diffusing the light irradiated on the surface is known.

  Moreover, there exist patent document 1, 2 as a prior art document relevant to the improvement of visibility, for example. In Patent Document 1, an indicator device (display device) including a light emitting element (light source) and a display window (display unit) through which light from the light emitting element is transmitted is disclosed. The indicator device includes a lens for guiding light from the light emitting element to the display window. Patent Document 1 proposes a technique for coaxially aligning the center positions of a light emitting element, a light receiving part of a lens, and a light emitting part for the purpose of achieving luminance necessary for an indicator device.

  Further, in Patent Document 2, an LED lamp (light source) is provided on one side of the light guide plate, and light from the LED lamp is transmitted through the light guide plate and emitted from the opposite side (display unit), thereby forming a line shape. A line illumination lamp (display device) for obtaining light is disclosed. In Patent Document 2, for the purpose of enabling both improvement in quality, improvement in productivity, and cost reduction, the light guide plate is divided and molded, and the light is reflected inside the light guide plate so that the light is efficiently used. A technique for often guiding light to the display unit is proposed.

Japanese Patent No. 3567558 Japanese Patent No. 4182039

  However, in the conventional display device, the light emitted from the light source is only transmitted through the transparent or translucent cover provided in the display unit. For this reason, the display portion having a large light emission area compared to the irradiation area of the light source or the display portion having an elongated shape has a problem that the peripheral portion is dark or a plurality of light sources are required when trying to emit light uniformly.

  In this regard, in the technique disclosed in Patent Document 1, light is collected using a lens in order to improve luminance. However, since the irradiation angle to the display unit is narrowed by the light collection, Only the central area is brightened, and the problem that the display part having a large light emitting area and the display part having an elongated shape emit light uniformly cannot be solved.

  Further, in the technique disclosed in Patent Document 2, light from a light source is efficiently guided to a display unit. However, the problem that a plurality of light sources are required to cause the display unit to emit light uniformly can be solved. Absent.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a display device that can emit light efficiently and uniformly with a small number of light sources.

In order to solve the above problems, the present invention provides a display device including a light source and a display unit that performs light emission display by being irradiated with light emitted from the light source.
A condensing lens that is provided between the light source and the display unit, and receives light from the light source and collects the light;
A diffusion lens provided between the light source and the display unit on the display unit side of the condenser lens, and the light emitted from the condenser lens is incident and diffuses the light; and
The display unit is irradiated with light emitted from the diffusion lens.

  According to this, since the light from the light source is incident on the condenser lens and condensed, it is possible to prevent the light from leaking to the surroundings. Further, the light from the condenser lens is incident on the diffusing lens and diffused, and the diffused light is irradiated onto the display unit, so that light can be irradiated over a wide range. Therefore, the display portion can emit light efficiently and uniformly.

Further, in the display device of the present invention, an inner layer is provided between the condenser lens and the diffusion lens, and is formed of a material having a refractive index lower than that of the condenser lens and the diffusion lens,
The condensing lens, the diffusion lens, and the inner layer are integrated.

  According to this, since the condensing lens and the diffusing lens are integrated via the inner layer, the handling of the condensing lens and the diffusing lens can be facilitated. Further, by providing an inner layer between the condenser lens and the diffusion lens, light from the condenser lens can be efficiently guided to the diffusion lens. As a result, the display unit can emit light more efficiently. In addition, the inner layer is made of a material having a lower refractive index than that of the condensing lens and the diffusing lens, so that light is refracted unnecessarily at the boundary between the condensing lens and the inner layer and the boundary between the diffusing lens and the inner layer. Can be prevented.

Further, in the display device of the present invention, the display unit is an elongated shape,
The condensing lens is characterized in that it collects light in the short side direction of the elongated shape of the display unit and does not collect light in the long side direction of the elongated shape of the display unit.

  According to this, since the condensing lens has a shape that condenses light in the short side direction in the elongated shape of the display unit, it is possible to prevent light from leaking in the short side direction and to efficiently display the display unit. Light can be irradiated. In addition, since the condensing lens has a shape that does not collect light in the long side direction of the elongated shape of the display unit, light can be irradiated over a wide range in the long side direction of the display unit. That is, even an elongated display portion can emit light efficiently and uniformly.

Further, in the display device of the present invention, the display unit is an elongated shape,
The diffusing lens has a shape that diffuses light in the long side direction of the elongated shape of the display unit and does not diffuse light in the short side direction of the elongated shape of the display unit.

  According to this, since the diffusion lens has a shape that diffuses light in the long side direction of the elongated shape of the display unit, it is possible to irradiate light in a wide range in the long side direction of the display unit. In addition, since the diffusion lens has a shape that does not diffuse light in the short side direction of the elongated shape of the display unit, it is possible to prevent light from leaking in the short side direction, and to efficiently irradiate the display unit with light. be able to. That is, even an elongated display portion can emit light efficiently and uniformly.

Further, these condenser lenses and diffusion lenses may be combined. That is, in the display device of the present invention, the display unit has an elongated shape,
The condensing lens is configured to collect light in the short side direction of the elongated shape of the display unit and not to collect light in the long side direction of the elongated shape of the display unit,
The diffusing lens has a shape that diffuses light in the long side direction of the elongated shape of the display unit and does not diffuse light in the short side direction of the elongated shape of the display unit.

  Thereby, it is possible to perform light-emitting display more efficiently and uniformly on the elongated display unit.

  In the display device of the present invention, the diffuser lens has a shape in which a central portion of the diffuser lens located directly below the light source via the condenser lens diffuses light more than a peripheral portion. Features.

  According to this, it is considered that a large amount of light from the light source is incident on the central part of the diffusing lens located directly under the light source via the condenser lens. The central part diffuses light more than the peripheral part. Therefore, it is possible to prevent the light irradiation from being biased near the center of the display portion. Therefore, the display portion can emit light more uniformly.

1 is a perspective view of a copying machine 1. FIG. It is sectional drawing of the display part 4 periphery. It is a figure explaining progress of the light from LED. It is a figure explaining the shape of a lens. It is a figure explaining that a display part can be made to light-emit. It is a figure explaining that a display part can be made to light-emit uniformly. It is a top view of the elongate display part 4. FIG. 11 is a cross-sectional view around a display unit 4 according to Modification 1. FIG. 11 is a cross-sectional view around a display unit 4 according to Modification 2. FIG. 14 is a cross-sectional view around a display unit 4 according to Modification 3. FIG.

  Hereinafter, embodiments of the display device of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a copying machine 1 for copying a document or the like to which the display device of this embodiment is applied. The copying machine 1 has an operation display unit 2 for performing various operations and displaying various states of the copying machine 1. The operation display unit 2 has a touch panel type operation unit 3, and the user touches the operation unit 3 to select the size of paper to be copied or the number of copies. be able to.

  The operation display unit 2 corresponds to a “display device” according to the present invention, and includes a display unit 4 that displays various states of the copying machine 1. The display unit 4 is a portion that emits light when the copying machine 1 is in a specific state. In other words, the display unit 4 is a part that displays that the copying machine 1 is in a specific state by emitting light. Examples of the state of the copying machine 1 include a state where the power is turned on, a state where copying is currently being performed, and a state where a paper jam has occurred. The operation display unit 2 has a plurality of display units 4, and each state of the copying machine 1 is assigned to each display unit 4. That is, for example, when a paper jam has occurred in the copying machine 1, the display unit 4 corresponding to the occurrence of the paper jam among the plurality of display units 4 emits light. Further, a symbol related to the state of the corresponding copying machine 1 (for example, a symbol of a battery as a symbol related to power ON) is written on the side of each display unit 4, and the user can display the emitted light. The state of the copying machine 1 can be grasped by visually recognizing the part 4 and the symbol written on the side.

  The operation display unit 2 includes a plate-shaped exterior plate 12 that constitutes a part of the exterior of the copying machine 1, and the operation unit 3 and the display unit 4 are provided in the surface of the exterior plate 12. ing.

  Here, FIG. 2 shows a cross-sectional view when the operation display unit 2 is cut so as to cross the arbitrary display unit 4 among the plurality of display units 4 of FIG. As shown in FIG. 2, a through hole is formed in the exterior plate 12, and the through hole serves as the display unit 4. A printed circuit board 11 is provided on the back side of the exterior plate 12. The printed circuit board 11 is provided with an LED 10 as a light source at a position corresponding to the display unit 4 (below the display unit 4). The LED 10 emits light based on a lighting signal from a drive circuit formed on the printed circuit board 11. Since the LED 10 is provided under the display unit 4, the light from the LED 10 travels toward the display unit 4. Therefore, the display unit 4 performs light emission display when the light from the LED 10 is irradiated (transmitted).

  A lens component 20 is provided between the display unit 4 and the LED 10. The lens component 20 includes a plurality of portions each having a different function. Specifically, the lens component 20 includes a convex lens 21, an inner layer 22, a concave lens 23, and a surface layer 24.

  The convex lens 21 corresponds to the “condensing lens” of the present invention, and is a lens that condenses incident light. In the present embodiment, the convex lens 21 is a so-called biconvex lens in which both end surfaces 211 and 212 are convex surfaces. The convex lens 21 is provided immediately above the LED 10 so that the light from the LED 10 is directly incident thereon. The convex lens 21 is formed of a light-transmitting material generally used as a lens material, such as glass or transparent resin (plastic).

  The concave lens 23 corresponds to the “diffusion lens” of the present invention, and is a lens that diffuses incident light. In the present embodiment, the concave lens 23 is a so-called biconcave lens in which both end surfaces 231 and 232 are concave surfaces. The concave lens 23 is provided closer to the display unit 4 than the convex lens 21 so that the light emitted from the convex lens 21 is incident thereon. The concave lens 23 is also made of a light transmissive material such as glass or transparent resin (plastic).

  The inner layer 22 is provided between the convex lens 21 and the concave lens 23, and is for integrating the convex lens 21 and the concave lens 23 through the inner layer 22. More specifically, in the inner layer 22, one end surface 221 is a concave surface having the same curvature as the curvature of the convex surface 212 of the convex lens 21. The concave surface 221 of the inner layer 22 and the convex surface 212 on the exit side of the convex lens 21 are connected, and the inner layer 22 and the convex lens 21 are integrated. The inner layer 22 has a convex surface with the other end surface 222 having the same curvature as that of the concave surface 231 of the concave lens 23. The convex surface 222 of the inner layer 22 and the concave surface 231 on the incident side of the concave lens 23 are connected, and the inner layer 22 and the concave lens 23 are integrated. Thus, the convex lens 21, the concave lens 23, and the inner layer 22 are integrated. Although the convex lens 21 and the concave lens 23 can be separate parts, product assembly becomes complicated if they are separate parts. By providing the inner layer 22, the convex lens 21 and the concave lens 23 can be formed as an integral part, so that handling can be facilitated.

  The inner layer 22 is also formed of a light transmissive material such as glass or transparent resin (plastic). However, since the inner layer 22 is mainly for integrating the convex lens 21 and the concave lens 23 as described above, it is not preferable that the light traveling direction be changed by the inner layer 22. Therefore, the inner layer 22 is formed of a material whose refractive index θ2 of the inner layer 22 is lower than the refractive index θ1 of the convex lens 21 (θ1> θ2) and lower than the refractive index θ3 of the concave lens 23 (θ3> θ2). This can prevent light from being unnecessarily refracted at the boundary between the convex lens 21 and the inner layer 22 and the boundary between the inner layer 22 and the concave lens 23.

  The surface layer 24 is provided across the display unit 4 from the concave surface 232 on the emission side of the concave lens 23, and is for matching the lens component 20 to the shape of the exterior plate 12. More specifically, the surface layer 24 is provided so as to fill a gap between the concave surface 232 and the through hole of the display unit 4. As a result, it is possible to avoid using the concave lens 23 as it is for a product exterior. Moreover, since the surface 121 of the exterior board 12 and the surface 241 of the surface layer 24 can be made into the same plane, it can prevent a design from being impaired.

  The surface layer 24 is formed of a light-transmitting material, but may be formed of a translucent resin such as milky white or gray in design. When the surface layer 24 is formed of a translucent resin, the display unit 4 can emit light with light. Even in this case, if the convex lens 21, the inner layer 22, and the concave lens 23 are formed of a transparent resin, the appearance is not impaired, and the light from the LED 10 is emitted more than when the entire lens component 20 is formed of a translucent resin. The transmittance can be improved and the luminous efficiency can be improved.

  In addition, since the surface layer 24 is provided mainly from the viewpoint of design as described above, it is not preferable that the traveling direction of light changes due to the presence of the surface layer 24. Therefore, the surface layer 24 is formed of a material (θ3> θ4) in which the refractive index θ4 of the surface layer 24 is lower than the refractive index θ3 of the concave lens 23. Thereby, it is possible to prevent the light from being unnecessarily refracted at the boundary between the concave lens 23 and the surface layer 24.

  Thus, the lens component 20 is configured by integrating the convex lens 21, the inner layer 22, the concave lens 23, and the surface layer 24 of different materials. The lens component 20 is formed using, for example, a two-color molding technique. However, since the lens component 20 is composed of four components 21 to 24, it is formed in four stages. That is, for example, the convex lens 21 is first formed by pouring the material of the convex lens 21 into the primary cavity. Thereafter, the material of the inner layer 22 is poured into the secondary cavity while leaving the convex lens 21 in the mold, and the inner layer 22 is formed integrally with the convex lens 21. Thereafter, the material of the concave lens 23 is poured into the tertiary cavity with the convex lens 21 and the inner layer 22 left in the mold, and the concave lens 23 is formed integrally with the convex lens 21 and the inner layer 22. Thereafter, the material of the surface layer 24 is poured into the quaternary cavity while leaving the convex lens 21, the inner layer 22, and the concave lens 23 in the mold, thereby forming the surface layer 24 integrally with the convex lens 21, the inner layer 22, and the concave lens 23. Thereby, the lens component 20 in which the convex lens 21, the inner layer 22, the concave lens 23, and the surface layer 24 are integrated can be formed. The order of forming the convex lens 21, the inner layer 22, the concave lens 23, and the surface layer 24 is not limited to the above order.

  Thus, since the lens component 20 including the convex lens 21 and the concave lens 23 is provided between the LED 10 and the display unit 4, the light from the LED 10 is efficiently and uniformly displayed by the action of the lens component 20. The part 4 can be irradiated. Here, FIG. 3 is a diagram for explaining how the light from the LED 10 travels inside the lens component 20 and is irradiated on the display unit 4. In FIG. 3, in general, in order to explain how light from an LED travels due to the presence of a convex lens and a concave lens and how the light is emitted to the display unit, the LED, the convex lens, and the concave lens In addition, the display surface (display unit) is given a reference different from that in FIG. Further, since the inner layer 22 and the surface layer 24 in FIG. 2 are not provided for the purpose of collecting or diffusing light, the inner layer and the surface layer are not shown in FIG.

  As shown in FIG. 3, a convex lens 102 (corresponding to the convex lens 21 in FIG. 2) is provided between the LED 101 (corresponding to the LED 10 in FIG. 2) and the display surface 104 (corresponding to the display unit 4 in FIG. 2). A concave lens 103 (corresponding to the concave lens 23 in FIG. 2) is provided on the display surface 104 side of the convex lens 102. That is, it is the same as the positional relationship of FIG. Since the light L1 from the LED 101 enters the convex lens 102 and is condensed (refracted) by the convex lens 102, the spread of the light L1 can be suppressed. Here, when the distance between the LED 101 and the convex lens 102 is the focal length f1 of the convex lens 102, the light L2 transmitted through the convex lens 102 becomes a parallel light beam having a width y1. In this case, the LED 101 is disposed at the focal point F1 of the convex lens 102. At this time, assuming that the light L1 from the LED 101 has a spread of the directivity angle 2θ, the width y1 of the light L2 is expressed by the following Expression 1.

  Parallel light L <b> 2 having a width y <b> 1 emitted from the convex lens 102 is incident on the concave lens 103 and is diffused by the concave lens 103. Then, the light L3 diffused through the concave lens 103 is irradiated onto the display surface 104. As a result, light can be irradiated over a wide area of the display surface 104. Here, if the irradiation width of the light L3 on the display surface 104 is y0, the focal length of the concave lens 103 (the distance between the focal point F2 and the concave lens 103) is f2, and the distance between the concave lens 103 and the display surface 104 is x2, the following formula 2 Is established. Furthermore, when Expression 2 is transformed, the irradiation width y0 is expressed by Expression 3 below.

  As shown in Expression 3, the irradiation width y0 depends on the width y1 of the light L2 emitted from the convex lens 102. Therefore, the irradiation width y0 can be adjusted by adjusting the width y1 of the light L2. . The width y1 of the light L2 depends on the focal length f1 of the convex lens 102 and the directivity angle 2θ of the light L1 from the LED 101 as shown in the above formula 1. Therefore, the focal length f1 and the directivity angle 2θ can be adjusted by appropriately determining the shape of the convex lens 102 and the LED 101 to be used, and thus the width y1 of the light L2 can be adjusted. As a result, the irradiation width y0 can be adjusted.

  Further, as shown in Expression 3, the irradiation width y0 depends on the focal length f2 of the concave lens 103. Therefore, by adjusting the focal length f2, that is, by appropriately determining the shape of the concave lens 103, the irradiation width y0. Can be adjusted.

  Further, as shown in Expression 3, the irradiation width y0 depends on the distance x2 between the concave lens 103 and the display surface 104. Therefore, by adjusting the distance x2, that is, by adjusting the arrangement position of the concave lens 103, The irradiation width y0 can be adjusted.

  In this way, considering the expression 3, the directivity angle 2θ, the focal length f1 of the convex lens 102, the focal length f2 of the concave lens 103, and the distance x2 between the concave lens 103 and the display surface 104 are determined according to the display surface 104. The display surface 104 can be irradiated with light L3 having an irradiation width y0. For example, by making the irradiation width y0 the same as the width of the display surface 104, the display surface 104 can emit light uniformly.

  Here, FIG. 4 shows how the focal length varies depending on the shape of the lens in order to form the convex lens 102 having the focal length f1 determined in consideration of Equation 3 and the concave lens 103 having the focal length f2. FIG. In FIG. 4, the reference numerals different from those in FIGS. 2 and 3 are attached in the sense of a general lens.

  As shown in FIG. 4, it is assumed that incident light L is incident on the lens 105. Further, if the radius of curvature of the curved surface 106 on the incident side of the lens 105 is R1, the radius of curvature of the curved surface 107 on the exit side is R2, the thickness of the lens 105 is d, and the refractive index of the lens 105 is n, the focal point of the lens 105 is obtained. The distance f is expressed by an approximate expression (lens formula) of Expression 4 below. In Equation 4, when the curved surfaces 106 and 107 are convex with respect to the incident direction of the incident light L, the curvature radii R1 and R have positive values. When the curved surfaces 106 and 107 are concave, the curvature radii R1 and R R is a negative value. In the case of FIG. 4, the curvature radius R1 of the curved surface 106 is a positive value, and the curvature radius R2 of the curved surface 107 is a negative value.

  Therefore, it is possible to obtain the desired focal length f by determining the shape of the lens 105 (curved radius of curvature, thickness, etc.) in consideration of Equation 4.

  2 are determined in terms of the arrangement position and shape from the viewpoints described above, that is, the radius of curvature and thickness of the convex surfaces 211 and 212 of the convex lens 21, and the radius of curvature and thickness of the concave surfaces 231 and 232 of the concave lens 23. By determining the arrangement positions of the lenses 21 and 23, the light from the LED 10 can be efficiently and uniformly irradiated onto the display unit 4.

  In FIG. 3, the LED 101 is described as being disposed at the focal point F1 of the convex lens 102. However, the LED 101 is not necessarily disposed at the focal point F1 of the convex lens 102. The LEDs 101 may be arranged so as to obtain an optimal light distribution according to the distance of the display surface 104, the width of the display surface 104, and the like. When the LED 101 is at a position farther than the focal length f1 of the convex lens 102, the light transmitted through the convex lens 102 is collected on the inner side, and the diffusion at the concave lens 103 is smaller than the parallel light. On the contrary, when the LED 101 is located at a position closer than the focal length F1, the light spreads slightly and the diffusion at the concave lens 103 is larger than that of the parallel light beam.

  Next, the fact that the display unit 4 can emit light brightly by adopting the configuration of FIG. 2 will be further described. Here, FIG. 5 is a diagram for explaining this. Specifically, FIG. 5A shows the amount of light applied to the display surface 104 in the configuration according to the present invention (configuration in FIG. 3). FIG. 5B is a diagram schematically illustrating the amount of light (brightness) irradiated on the display surface 104 in the conventional configuration. In FIG. 5, components having the same functions as those shown in FIG. In FIG. 5, the light emitted from the LED 101 is represented by a line, and the amount of light (brightness) is represented by the number of the lines.

  As shown in FIG. 5A, in the configuration according to the present invention, as described above, the light L1 from the LED 101 is collected by the convex lens 102, so that the light L1 is prevented from diverging. it can. The light L2 collected by the convex lens 102 is diffused by the concave lens 103, and the diffused light L3 is irradiated on the display surface 104. The number of lines of light L3 irradiated on the display surface 104 is 33. On the other hand, as shown in FIG. 5B, in the conventional configuration, the light L4 from the LED 101 diverges at the directivity angle 2θ (see FIG. 3), and is the number of the light L4 that reaches the display surface 104. Is assumed to be 15. As described above, by adopting the configuration of the present invention (particularly, by providing the convex lens 102), it can be seen that the brightness of light is brighter than that of the conventional display surface 104.

  Even in the conventional configuration shown in FIG. 5B, if the display surface 104 has a circular or square shape, the brightness of the display surface 104 can be changed by adjusting the distance of the LED 101. When the display surface 104 has a rectangular or elongated shape, the display surface 104 cannot emit light uniformly only by the distance of the LED 101. In this regard, in the configuration according to the present invention shown in FIG. 5A, if light is condensed and diffused as a lens shape that matches the shape of the display surface 104, light leaking outside the display surface 104 can be suppressed, and The display surface 104 can emit light uniformly. For example, in the case of the rectangular display surface 104, the cross-sectional shapes of the convex lens 102 and the concave lens 103 are made different between the short side direction and the long side direction of the display surface 104, thereby collecting light in the short side direction and the long side direction. The degree of light and diffusion can be changed. Therefore, light can be emitted efficiently and uniformly even on the rectangular display surface 104.

  Next, it will be further described that by adopting the configuration of FIG. 2, even when the display unit 4 is wide, the display unit 4 can emit light uniformly. Here, FIG. 6 is a diagram for explaining this, and specifically, FIG. 6A shows the irradiation of light with which the display surface 104 is irradiated in the configuration according to the present invention (configuration in FIG. 3). FIG. 6B is a diagram schematically illustrating the width of light irradiated on the display surface 104 in the conventional configuration. In FIG. 6, components having the same functions as those shown in FIG. Moreover, in FIG. 6, the light emitted from LED101 is represented by the line.

  As shown in FIG. 6A, in the configuration according to the present invention, the light L <b> 1 from the LED 101 is collected by the convex lens 102, and the collected light L <b> 2 is diffused by the concave lens 103. Therefore, the diffused light L3 can be irradiated over a wide area of the display surface 104. In FIG. 6A, the light L <b> 3 is irradiated on the entire display surface 104.

  On the other hand, in the conventional configuration shown in FIG. 6B, a plurality of LEDs are required to irradiate the entire display surface 104 with light. That is, in FIG. 6B, three LEDs 101a to 101c are arranged side by side. The LEDs 101a to 101c are the same LEDs as each other, and are also the same as the LEDs 101 in FIG. Each LED 101a to 101c alone cannot irradiate light on the entire display surface 104, and irradiates a part of the display surface 104 with light. Specifically, the light L41 from the uppermost LED 101a in FIG. Further, the light L42 from the middle LED 101b irradiates the central portion of the display surface 104. Further, light L43 from the lowermost LED 101c illuminates the lower portion of the display surface 104. Thus, the entire area of the display surface 104 can be made to emit light by the lights L41 to L43 from the three LEDs 101a to 101c.

  Thus, by adopting the configuration of the present invention (especially by providing the concave lens 103), it can be seen that if the diffusion by the concave lens 103 is increased, the display surface 104 can uniformly emit light even with a small number of LEDs.

  As described above, in this embodiment, since the lens component 20 including the convex lens 21 and the concave lens 23 is provided between the display unit 4 and the LED 10 of the copying machine 1, the light from the LED 10 is efficiently and uniformly distributed. The display unit 4 can be irradiated. Therefore, the display part 4 can be made to light-emit uniformly.

(Modification 1)
Next, a first modification of the display device according to the present invention will be described. Since general LEDs are made so that light spreads in a circular shape, for example, when the display is elongated, when viewed from the front (short side) and from the side (long side) Then, unless the light is condensed and diffused differently, the display portion cannot be made to emit light efficiently. In the first modification, even when the display unit has an elongated shape, the display unit can emit light efficiently.

  FIG. 7 is a plan view of the display unit 4 according to the first modification. As shown in FIG. 7, the display unit 4 has a rectangular shape (elongated shape) having a short side 41 and a long side 42. Here, FIG. 8 shows a cross-sectional view when the operation display unit 2 is cut so as to cross the arbitrary display unit 4 among the plurality of display units 4 of FIG. More specifically, FIG. 8A is a cross-sectional view when the display unit 4 is cut along a line parallel to the short side 41 of FIG. 7, and FIG. 8B is a long side 42 of FIG. It is sectional drawing when the display part 4 is cut | disconnected by the line parallel to the. In FIG. 8, parts having the same names as the parts in FIG.

  The convex lens 21 has different cross-sectional shapes in the front direction (short side direction) in FIG. 8A and the side direction (long side direction) in FIG. Specifically, the convex lens 21 is formed in an elongated shape according to the shape of the display unit 4, and its end surface 211 is curved in a convex shape in the short side direction (see FIG. 8A), and in the long side direction. Is a straight shape (see FIG. 8B). That is, the convex lens 21 has a shape that collects light in the short side direction but does not collect light in the long side direction.

  In addition, the concave lens 23 is also elongated in accordance with the shape of the display unit 4, and in the front direction (short side direction) in FIG. 8A and the side direction (long side direction) in FIG. The cross-sectional shape is different. Specifically, the end surface 231 of the concave lens 23 is straight in the short side direction (see FIG. 8A), and is curved in a concave shape in the long side direction (see FIG. 8B). . That is, the concave lens 23 has a shape that does not diffuse light in the short side direction but diffuses light in the long side direction. Components other than the convex lens 21 and the concave lens 23 are the same as those in FIG.

  By forming the convex lens 21 and the concave lens 23 as shown in FIG. 8, the light from the LED 10 can be efficiently irradiated onto the display unit 4. That is, the light L <b> 1 from the LED 10 travels so as to spread at a certain directivity angle and enters the convex lens 21. At this time, the light L1 is collected in the short side direction by the convex lens 21, and thus the spread of light in the short side direction (light leakage) can be suppressed (see FIG. 8A). In FIG. 8A, the light L1 is collected by the convex lens 21 into the parallel light L2 in the short side direction. On the other hand, the light L1 from the LED 10 is not collected in the long-side direction in the convex lens 21, so that the light L1 incident on the convex lens 21 is emitted from the convex lens 21 as it is (see FIG. 8B). .

  The light L2 emitted from the convex lens 21 travels through the inner layer 22 as parallel light in the short side direction and spreads in the long side direction, and is incident on the concave lens 23. At this time, since the light L2 is not diffused in the short side direction in the concave lens 23, light L3 having substantially the same width as the incident light L2 is emitted from the concave lens 23 (see FIG. 8A). Therefore, it is possible to suppress light leakage with respect to the short side direction of the display unit 4, and to efficiently irradiate the display unit 4 with light.

  On the other hand, the light L2 incident on the concave lens 23 is diffused in the long side direction by the concave lens 23, so that the light L3 having a larger spread than the light L2 is emitted from the concave lens 23 (FIG. 8B). )reference). Therefore, light can be irradiated over a wide range with respect to the long side direction of the display unit 4. As described above, even when the elongated display unit 4 is elongated, light loss can be minimized and the light emission efficiency of the display unit 4 can be improved.

(Modification 2)
Next, a second modification of the display device according to the present invention will be described. Since the light from the LED is irradiated to the display unit with a certain spread, it is considered that the portion immediately below the LED in the display unit is brightest. In other words, as shown in FIG. 5A, when the brightness of light is considered in terms of the number of light lines, the number of light lines irradiated to the central part located directly below the LED in the display part. However, it is larger than the number irradiated to the peripheral part (it can be considered that the distance between the lines of light is the densest in the central part). In the second modification, the display unit 4 emits light more uniformly in consideration of the difference in brightness between the central part of the display unit 4 and its peripheral part.

  FIG. 9 shows a cross-sectional view corresponding to FIG. In FIG. 9, parts having the same names as the parts in FIG. As shown in FIG. 9, the concave lens 23 has a shape in which the central portion of the curved surface 231 on the incident side is recessed. More specifically, in the concave lens 23, the curvature of the central curved surface 231a is smaller than the curvature of the peripheral curved surface 231b other than the curved surface 231a. According to this, when the radius of curvature of the lens becomes smaller from the above equation 4, the focal length becomes shorter, so that the concave lens 23 diffuses the light incident on the central portion 231a than the light incident on the peripheral portion 231b. . The components other than the concave lens 23 are the same as those in FIG.

  By forming the concave lens 23 as shown in FIG. 9, the display unit 4 can emit light more uniformly. That is, among the light L2 incident on the concave lens 23, the light L2 incident on the central portion 231a is more diffused, so that the irradiation of the light L3 near the center of the display portion 4 can be prevented. .

(Modification 3)
Next, a third modification of the display device according to the present invention will be described. In the above embodiment, a concave lens is used as a lens for diffusing light. However, a method for diffusing light may not be a concave lens. Here, FIG. 10 shows a cross-sectional view corresponding to FIG. In FIG. 10, parts having the same names as the parts in FIG. As shown in FIG. 10, the concave lens is not provided, and the inner layer 22 and the surface layer 24 are directly connected to each other at end surfaces 222 and 242. However, the end surface 222 of the inner layer 22 and the end surface 242 of the surface layer 24 have the same uneven shape. Thus, when the light traveling through the inner layer 22 is incident on the end surface 242 of the surface layer 24, the light is irregularly reflected, that is, diffused by the uneven shape of the end surface 242.

  Further, the size and density of the unevenness of the end surface 222 and the end surface 242 may be changed depending on the part. Thereby, the display unit 4 can emit light more uniformly. For example, in FIG. 10, the density of the unevenness is larger in the central part of the inner layer 22 (end face 222) and the surface layer 24 (end face 242) located immediately below the LED 10 than in the peripheral part. Therefore, the diffusion of light in the central portion can be made larger than that in the peripheral portion, and the light irradiation can be prevented from being biased near the center of the display portion 4. These end surfaces 222 and 242 correspond to the “diffuse lens” of the present invention.

  In addition to the above-described embodiment, the display device of the present invention can be modified without departing from the scope of the claims. For example, in the above embodiment, an example in which a biconvex lens is used as a convex lens and a biconcave lens is used as a concave lens has been described. Moreover, you may employ | adopt a Fresnel lens in order to make it thin shape. Moreover, you may make it the shape which arranged the some lens as a condensing lens or a diffusion lens. By carrying out like this, the light from LED can be irradiated to a display part more uniformly. Further, the present invention may be applied to various machines other than copying machines.

1 Copier 2 Operation display (display device)
DESCRIPTION OF SYMBOLS 3 Operation part 4,104 Display part 41 The short side in the elongate shape of the display part 42 42 The long side in the elongate shape of the display part 4, 101 LED (light source)
DESCRIPTION OF SYMBOLS 11 Printed circuit board 12 Exterior board 20 Lens components 21, 102 Convex lens (Condensing lens)
22 Inner layer 23, 103 Concave lens (diffuse lens)
24 Surface layer 211 End surface on the incident side of the convex lens 21 212 End surface on the output side of the convex lens 21 221 End surface on the incident side of the inner layer 22 222 End surface on the output side of the inner layer 231 End surface on the incident side of the concave lens 23 232 End surface on the output side of the concave lens 23 231a End face of the central part of the concave lens 23 231b End face of the peripheral part of the concave lens 23 241 End face of the outgoing side of the surface layer 24 242 End face of the incident side of the surface layer 24

Claims (6)

In a display device comprising: a light source; and a display unit that performs light emission display by being irradiated with light emitted from the light source.
A condensing lens that is provided between the light source and the display unit, and receives light from the light source and collects the light;
A diffusion lens provided between the light source and the display unit on the display unit side of the condenser lens, and the light emitted from the condenser lens is incident and diffuses the light; and
The display device, wherein the display unit is irradiated with light emitted from the diffusion lens. Provided between the condenser lens and the diffusion lens, comprising an inner layer made of a material having a lower refractive index than the condenser lens and the diffusion lens,
The display device according to claim 1, wherein the condenser lens, the diffusing lens, and the inner layer are integrated. The display unit is an elongated shape,
The condensing lens has a shape that collects light in a short side direction of the elongated shape of the display unit and does not collect light in a long side direction of the elongated shape of the display unit. Item 3. The display device according to Item 1 or 2. The display unit is an elongated shape,
The diffuser lens has a shape that diffuses light in a long side direction of the elongated shape of the display unit and does not diffuse light in a short side direction of the elongated shape of the display unit. 2. The display device according to 2. The display unit is an elongated shape,
The condensing lens is configured to collect light in the short side direction of the elongated shape of the display unit and not to collect light in the long side direction of the elongated shape of the display unit,
The diffuser lens has a shape that diffuses light in a long side direction of the elongated shape of the display unit and does not diffuse light in a short side direction of the elongated shape of the display unit. 2. The display device according to 2.   3. The diffuser lens according to claim 1, wherein a central portion of the diffuser lens positioned directly below the light source via the condenser lens has a shape that diffuses light more than a peripheral portion. The display device described.

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