JP2008145657A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of clearly displaying an image made latent on a light guide plate. <P>SOLUTION: The display device A1 includes first and second light guide plates 4A and 4B having incident surfaces 41A and 41B, reflecting surfaces 42A and 42B where reflecting regions 42Aa and 42Ba formed in the shape of an image to be displayed, and projection surfaces 43A and 43B, and first and second light sources 3A and 3B disposed right in front of the incident surfaces 41A and 41B, and is configured to display the arbitrary image through the projection surfaces 43A and 43B by reflecting light beams L1 and L2 made incident from the incident surfaces 41A and 41B by the reflecting surfaces 42A and 42B forward in a projection direction, the display device having a dimming transmission film 6 disposed in front of the light guide plates 4A and 4B in the projection direction and reducing the quantity of transmitted light without varying its color temperature and a dark color surface 5a disposed behind the light guide plates 4A and 4B in the projection direction and reducing the quantity of reflected light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device that visualizes a desired image latently imaged on a light guide plate with light from a light source.

  FIG. 9 shows an example of a conventional display device (see, for example, Patent Document 1). The display device X shown in the figure includes a case 91, a substrate 92, first and second light sources 93A and 93B, first and second light guide plates 94 and 95, and a mask sheet 96. The first and second light sources 93 </ b> A and 93 </ b> B are LED elements and are mounted on the substrate 92. The substrate 92 and the first and second light sources 93A and 93B are accommodated in a case 91. The first and second light guide plates 94 and 95 are substantially rectangular plates made of transparent epoxy resin, and are laminated in the case 91. The first and second light guide plates 94 and 95 are formed with entrance surfaces 94a and 95a, reflection surfaces 94b and 95b, exit surfaces 94c and 95c, and end surfaces 94d and 95d. The incident surfaces 94a and 95a are surfaces on which the lights L1 and L2 from the first and second light sources 93A and 93B are incident. The reflecting surfaces 94b and 95b are surfaces that reflect the light L1 and L2 from the incident surfaces 94a and 95a toward the emitting surfaces 94c and 95c. The end surfaces 94d and 95d are surfaces for directing the lights L1 and L2 traveling through the first and second light guide plates 94 and 95 to the reflecting surfaces 94b and 95b.

  Each of the reflection surfaces 94b and 95b is provided with a reflection region (not shown). This reflection region is a region where grooves, dots, or rough surfaces by etching are formed on arbitrary portions of the reflection surfaces 94b and 95b. Of the reflecting surfaces 94b and 95b, the light L1 and L2 are reflected by the portion where the reflecting region is formed. The reflective region of the first light guide plate 94 and the reflective region of the second light guide plate 95 have different shapes in plan view. When only the first light source 93A is turned on, an arbitrary image latently formed as a reflection region shape on the first light guide plate 94 is visualized by the light L1 emitted from the light emitting surface 94c. On the other hand, when only the second light source 93B is turned on, another image latently imaged as the shape of the reflection region on the second light guide plate 95 is visualized by the light L2 emitted from the light emission surface 95c. Thus, according to the display device X, two types of images having different shapes can be displayed using the opening 96a of the mask sheet 96 as a display region.

  However, it is difficult to display the latent images on the first and second light guide plates 94 and 95 individually and clearly. First, it is inevitable that the light L1 and L2 are slightly reflected even in regions other than the above-described reflective regions of the reflective surfaces 94b and 95b. The reflection by the area other than the reflection area causes the contrast to be lowered when the latent images are displayed on the first and second light guide plates 94 and 95, respectively. For example, when displaying the latent image on the first light guide plate 94 by turning on only the first light source 93 </ b> A, a part of the light L <b> 1 reflected by the end surface 94 d is reflected on the reflection surface 95 b of the second light guide plate 95. May be reached. In such a case, there is a problem in that not only the latent image is displayed on the first light guide plate 94 but also the latent image formed on the second light guide plate 95 appears.

Registered Utility Model No. 3010460

  The present invention has been conceived under the circumstances described above, and it is an object of the present invention to provide a display device capable of clearly displaying an image latent imaged on a light guide plate.

  The display device provided by the present invention has an incident surface facing in a direction perpendicular to the thickness direction that coincides with the emission direction, and a reflection region that is located behind the emission direction and has an image shape to be displayed. Light that has been formed and includes one or more light guide plates having an exit surface that is located in front of the exit direction, and one or more light sources that are located in front of the entrance surface. The display device is configured to display an arbitrary image through the emission surface by reflecting the image to the front in the emission direction by the reflection surface, and is positioned forward in the emission direction with respect to the light guide plate. And a light-reducing and transmitting layer that reduces the amount of light without changing the color temperature of the transmitted light, and a dark color surface that is located behind the light guide plate in the emission direction and that reduces the amount of reflected light. It is characterized by having There.

  According to such a structure, the light which leaked from the part other than the said reflection area to the emission direction back among the said reflective surfaces can be absorbed by the said dark color surface. Further, the light passing from the part other than the reflection region to the front in the emission direction through the emission surface can be made an amount of light that is hardly noticeable by the light reducing transmission layer. Therefore, the amount of light reflected by the reflection region can be made relatively large, and the contrast when the latent image is displayed on the light guide plate can be improved.

  In a preferred embodiment of the present invention, the first and second light guide plates stacked in the emission direction, the first light source located in front of the incident surface of the first light guide plate, and the second light guide plate described above. A second light source located in front of the incident surface; a case for accommodating the first and second light guide plates and the first and second light sources; and the incident surface of the first light guide plate; The end surface located on the opposite side is farther from the incident surface of the first light guide plate than the end surface located on the opposite side of the incident surface of the second light guide plate in the emission direction view. And a portion that is in contact with the first light guide plate from the second light guide plate side and is located between the end surface of the first light guide plate and the end surface of the second light guide plate in the emission direction view. Above the first contact surface and the second light guide plate The first light guide plate and a second abutment surface that abuts the from the opposite side, are formed. According to such a configuration, when the first light source is turned on, the light reflected toward the second light guide plate by the end surface can be appropriately blocked by the first contact surface. . Therefore, the latent image on the first and second light guide plates can be clearly displayed.

  In a preferred embodiment of the present invention, the end surface of the first light guide plate is inclined so as to be separated from the incident surface of the first light guide plate as it is separated from the second light guide plate in the emission direction. Yes. According to such a configuration, it is possible to appropriately prevent light from being reflected from the end surface of the first light guide plate toward the second light guide plate.

  In a preferred embodiment of the present invention, a distance in the emission direction between the first contact surface and the second contact surface is larger than the thickness of the second light guide plate. According to such a configuration, it is possible to provide a gap between the first light guide plate and the second light guide plate. Due to this gap, it is possible to reflect light that travels inappropriately from the first light guide plate to the second light guide plate.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1 to 5 show a first embodiment of a display device according to the present invention. The display device A1 of the present embodiment includes a case 1, a substrate 2, two first light sources 3A, two second light sources 3B, two first light guide plates 4A, two second light guide plates 4B, and two dark color sheets 5. , A light reducing transmission film 6 and a mask sheet 7. The display device A1 is configured to be able to arbitrarily switch and display the image shown in FIG. 1 and the image shown in FIG.

  As an application of the display device A1, for example, background display of a switch of an electronic device can be cited. By adopting a configuration in which a transparent touch panel is superimposed on the display device A1, it is possible to assign two functions to one switch. By appropriately switching the display on the display device A1, the user can appropriately recognize which function the switch performs.

  The case 1 has a substantially rectangular parallelepiped shape as a whole, and is made of, for example, a white resin. As shown in FIG. 5, the case 1 is formed with a recess for accommodating the substrate 2, the first and second light sources 3A and 3B, the first and second light guide plates 4A and 4B, and the dark color sheet 5. Yes. Part of the surface forming the recess is a first contact surface 11 and a second contact surface 12. The second contact surface 12 is located deeper in the recess than the first contact surface. The first contact surface 11 is substantially annular and has a shape surrounding the second contact surface 12 in plan view. In the case 1, a connector 12 is formed. The connector 12 is used for supplying power to the display device A1 and inputting a display switching command.

  The substrate 2 is an elongated insulating substrate and is made of, for example, a glass epoxy resin. On the substrate 2, two first light sources 3A and two second light sources 3B are mounted.

  The first light source 3 </ b> A is a light source for visualizing an image latent image on the first light guide plate 4 </ b> A, and includes, for example, two LED elements 31. The second light source 3B is a light source for visualizing an image latent imaged on the second light guide plate 4B, and includes, for example, two LED elements 31. As shown in FIGS. 1 and 2, the two first light sources 3 </ b> A are spaced apart in the longitudinal direction of the substrate 2. In addition, as shown in FIG. 3, each second light source 3 </ b> B is disposed adjacent to each first light source 3 </ b> A in the width direction of the substrate 2.

  The two first light guide plates 4A are spaced apart from each other along the longitudinal direction of the substrate 2 as shown in FIGS. The first light guide plate 4A is made of, for example, a transparent epoxy resin and has a polygonal shape. The first light guide plate 4A is formed with an incident surface 41A, a reflective surface 42A, an output surface 43A, a pair of side surfaces 44A, and an end surface 45A.

  The incident surface 41A is located in front of the first light source 3A, and is a surface on which the light L1 from the first light source 3A is incident. The reflective surface 42A is a surface in which a reflective region 42Aa is formed. As shown in FIG. 5, the reflective region 42Aa is a region where grooves, dots, or a rough surface by etching is formed on the reflective surface 42A. The reflection area 42Aa has a shape of an image to be latent imaged on the first light guide plate 4A. Of the light L1 that has traveled toward the reflection surface 42A, the light that has reached the reflection region 42Aa is reflected toward the emission surface 43A.

  The emission surface 43A is a surface for emitting the light L1 coming from the reflection region 42Aa. The end surface 45A is located on the side opposite to the incident surface 41A, and is a surface for turning back the light L1 traveling in the first light guide plate 4A toward the first light guide plate 4A. In the present embodiment, the end surface 45A is inclined so as to be separated from the incident surface 41A as the distance from the second light guide plate 4B increases. The pair of side surfaces 44A are spaced apart in a direction perpendicular to the direction in which the incident surface 41A and the end surface 45A are separated. Similar to the end face 45A, the side face 44A is inclined so as to become wider toward the front in the emission direction.

  The two second light guide plates 4B are spaced apart from each other along the longitudinal direction of the substrate 2 as shown in FIGS. Further, as shown in FIGS. 3 and 4, each second light guide plate 4 </ b> B is disposed rearward in the emission direction with respect to each first light guide plate 4 </ b> A. Similarly to the first light guide plate 4A, the second light guide plate 4B is formed with an incident surface 41B, a reflective surface 42B, an output surface 43B, a pair of side surfaces 44B, and an end surface 45B.

  A reflection area 42Ba having the same structure as the reflection area 42Aa is formed in the reflection surface 42B. The reflection region 42Ba has a shape of an image to be latent imaged on the second light guide plate 4B. The pair of side surfaces 44B and the end surface 45B are inclined so as to expand toward the front in the emission direction. As shown in FIGS. 1 and 2, the second light guide plate 4B has a smaller size in plan view than the first light guide plate 4A. That is, the pair of side surfaces 44B and the end surface 45B are disposed inwardly in a plan view of the first light guide plate 4A than the pair of side surfaces 44A and the end surface 45A.

  The two dark sheets 5 are, for example, black or dark gray resin sheets. The dark color sheet 5 is disposed behind the second light guide plate 4B in the emission direction. The dark color sheet 5 is provided to form a black or dark gray dark color surface 5a.

  The mask sheet 7 is made of, for example, an opaque resin, and is disposed forward in the emission direction with respect to the first light guide plate 4A. Two openings 7 a are formed in the mask sheet 7. The opening 7a has a smaller size in plan view than the emission surfaces 43A and 43B.

  The light reduction transmission film 6 is an example of the light reduction transmission layer referred to in the present invention, and is a gray film that can reduce the amount of light without changing the color temperature of the transmitted light. It is called. The light reducing transmission film 6 is disposed forward of the first light guide plate 4A in the emission direction and covers the two openings 7a.

  As shown in FIG. 5, when assembling the display device A1, the two dark sheets 5, two second light guide plates 4B, and two first light guide plates 4A are inserted into the case 1 in this order. The second light guide plate 4B is positioned in the case 1 by contacting the second contact surface 12. When the second light guide plate 4B is inserted, the first contact surface 11 surrounds the second light guide plate 4B. The first light guide plate 4A is positioned by contacting the first contact surface 11. As shown in FIGS. 3 and 4, the distance between the first contact surface 11 and the second contact surface 12 in the emission direction is larger than the thickness of the second light guide plate 4B. Thereby, a gap is generated between the first light guide plate 4A and the second light guide plate 4B.

  Next, the operation of the display device A1 will be described.

  According to this embodiment, it is possible to clearly display images latent images on the first light guide plate 4A and the second light guide plate 4B. For example, when the second light source 3B is turned on, part of the light L2 leaks backward from the region other than the reflective region 42Ba in the reflective surface 42B. Much of the leaked light L2 can be absorbed by the dark color surface 5a. Thereby, the contrast of the image visualized by the light reflected by the reflection region 42Ba can be improved.

  Further, it is possible to almost absorb the slight light L2 that cannot be absorbed by the dark color surface 5a by the light reducing transmission film 6. On the other hand, since the light L2 reflected by the reflection region 42Ba has a relatively large amount of light, the amount of light L2 is relatively large even after passing through the light reducing transmission film 6. With the function of the light reducing transmission film 6, the contrast of the image visualized by the light reflected by the reflection region 42Ba can be further improved. Needless to say, the reduced light transmission film 6 can improve the contrast of not only the second light guide plate 4B but also the image visualized by the light reflected by the reflection region 42Aa of the first light guide plate 4A. Yes.

  Another effect of the light-reducing and transmitting film 6 is to prevent it from being erroneously visualized by external light. That is, when the first and second light sources 3A and 3B are not turned on, when external light is incident on the first light guide plate 4A or the second light guide plate 4B, the light is reflected on the reflection regions 42Aa and 42Ba. The image may appear slightly. By providing the light reducing transmission film 6, it is possible to almost absorb the slight external light reflected by the reflection regions 42Aa and 42Ba. As a result, it is possible to prevent the image from slightly emerging due to the incidence of external light.

  The first contact surface 11 is provided on the inner side in a plan view with respect to the pair of side surfaces 44A and the end surface 45A. For this reason, when the first light source 3A is turned on, the first contact surface 11 causes the light that is directed to the second light guide plate 4B out of the light L1 reflected by the pair of side surfaces 44A and the end surface 45A. It is possible to block. Therefore, when it is desired to display the latent image on the first light guide plate 4A by turning on the first light source 3A, the latent image on the second light guide plate 4B is displayed by reflected light. It can be prevented appropriately. In addition, since the pair of side surfaces 44A and the end surface 45A are inclined surfaces that expand toward the front in the emission direction, the light L1 can be further prevented from unjustly heading toward the second light guide plate 4B. .

  A gap is provided between the first light guide plate 4A and the first light guide plate 4B. By providing this gap, an interface between air and a transparent epoxy resin is formed. This interface functions to reflect the light L1 that travels from the first light guide plate 4A to the second light guide plate 4B. Therefore, for example, compared to a configuration in which the first light guide plate 4A and the second light guide plate 4B are in close contact with each other, it is possible to prevent the light L1 from being incident on the second light guide plate 4B from the first light guide plate 4A. be able to.

  As described above, when the display device A1 is manufactured, the second light guide plate 4B and the first light guide plate 4A are sequentially inserted into the case 1 even though the light L1 can be appropriately prevented from leaking. It is sufficient to do the simple work of doing this, and there is no need to provide a dedicated light shielding plate. This is suitable for improving the manufacturing efficiency of the display device A1.

  6 to 8 show other embodiments of the present invention. In these drawings, the same or similar elements as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment.

  FIG. 6 shows a second embodiment of the display device according to the present invention. The display device A2 of the present embodiment is different from the above-described embodiments in the positions of the first light guide plate 4A and the second light guide plate 4B in the emission direction. In the present embodiment, the first light guide plate 4A is located behind the second light guide plate 4B in the emission direction. The point that the end surface 45A is farther from the incident surface 41A than the end surface 45B is the same as in the above-described embodiment. Although not shown in the figure, the point that the pair of side surfaces 44A are located outside the pair of side surfaces 44B in plan view is the same as that of the first embodiment. The end face 45A has a divergent shape toward the rear in the emission direction. This is the same as the first embodiment in that it is inclined so as to be separated from the incident surface 41A as it is separated from the second light guide plate 4B. A plurality of protrusions 4Ba are formed on the second light guide plate 4B. The plurality of protrusions 4Ba are arranged near the end of the second light guide plate 4B and are in contact with the first light guide plate 4A. The case 1 has an opening 1a. The opening 1a is for emitting the light from the first and second light guide plates 4A and 4B to the outside of the display device A2, similarly to the opening 7a in the first embodiment described above. Also in the manufacturing process of the display device A2, after the second light guide plate 4B is inserted into the case 1 until it comes into contact with the second contact surface 11B of the case 1, the first light guide plate is brought into contact with the first contact surface 11A. 4A is inserted into the case 1.

  Also in such an embodiment, the latent images on the first and second light guide plates 4A and 4B can be clearly displayed by the action of the dark color sheet 5 and the light reducing transmission film 6. Of the light L1 from the first light source 3A, the light reflected by the end face 45A in the direction toward the second light guide plate 4B can be appropriately blocked by the first contact surface 11A. The inclination of the end face 45A described above is advantageous in preventing the light L1 from being unduly directed toward the second light guide plate 4B. Further, since the plurality of protrusions 4Ba are provided, a gap is formed between the first light guide plate 4A and the second light guide plate 4B. This gap can prevent the light L2 from entering the first light guide plate 4A from the second light guide plate 4B.

  FIG. 7 shows a third embodiment of the display device according to the present invention. The display device A3 of the present embodiment includes one light source 3 and one light guide plate 4. The light guide plate 4 has an incident surface 41, a reflective surface 42, an exit surface 43, and an end surface 45. In the reflection surface 42, a reflection region 42a having an image shape to be displayed is formed. The display device A <b> 3 is a device for displaying one type of image latent image on the light guide plate 4. Even in such an embodiment, the latent image on the light guide plate 4 can be clearly displayed by the action of the dark color sheet 5 and the light reducing transmission film 6.

  FIG. 8 shows a fourth embodiment of the display device according to the present invention. The display device A4 of the present embodiment is different from the first embodiment described above in the configuration of the substrate 2 and the first and second light sources 3A and 3B. In the present embodiment, the first and second light sources 3 </ b> A and 3 </ b> B are separately mounted on the front and back surfaces of the substrate 2. The substrate 2 is accommodated in the case 1 in a posture that is perpendicular to the substrate 2 in the display device A1 of the first embodiment. The first light source 3A is disposed outward in plan view from the second light source 3B. The first light source 3 </ b> A and the second light source 3 </ b> B are configured by a so-called side view type LED element 31.

  According to such a configuration, it is possible to reduce the height of the first and second light sources 3A and 3B in the emission direction. Thereby, the thickness of the first and second light guide plates 4A and 4B can be reduced, and the entire display device A4 can be reduced in thickness. Further, when the first light source 3A is turned on, the light L1 directly traveling from the first light source 3A to the second light guide plate 4B is appropriately blocked by the portion of the substrate 2 where the second light source 3B is mounted. Is possible. This is advantageous for improving the contrast of the image latently imaged on the first light guide plate 4A.

  The display device according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the display device according to the present invention can be modified in various ways.

  The number of light guide plates provided in the display device according to the present invention is not limited to one or two, and may be three or more. The configuration of the reflection region may be any as long as the light traveling in the light guide plate can be appropriately reflected on the emission surface. If only the end surface of the first light guide plate is farther from the first light source than the end surface of the second light guide plate, for example, the pair of side surfaces of the first light guide plate and the second light guide plate overlap each other in plan view. It may be a configuration. A dark color surface is not limited to what was comprised by one surface of the dark color sheet, For example, you may form by making the inner surface of a case into a dark color. The light-reducing and transmitting layer referred to in the present invention is not limited to a light-reducing and transmitting film, and for example, may be a structure in which a coating capable of exhibiting a function of reducing and transmitting light is applied to one side of a transparent plate.

1 is a plan view showing a first embodiment of a display device according to the present invention. 1 is a plan view showing a first embodiment of a display device according to the present invention. It is sectional drawing which follows the III-III line of FIG. It is principal part sectional drawing in alignment with the IV-IV line of FIG. 1 is an exploded perspective view showing a first embodiment of a display device according to the present invention. It is sectional drawing which shows 2nd Embodiment of the display apparatus which concerns on this invention. It is sectional drawing which shows 3rd Embodiment of the display apparatus which concerns on this invention. It is sectional drawing which shows 4th Embodiment of the display apparatus which concerns on this invention. It is sectional drawing which shows an example of the conventional display apparatus.

Explanation of symbols

A1, A2, A3, A4 Display devices L, L1, L2 Light 1 Case 2 Substrate 3 Light source 3A First light source 3B Second light source 4 Light guide plate 4A First light guide plate 4B Second light guide plate 5 Dark color sheet 5a Dark color surface 6 Reduction Light transmission film (light attenuation transmission layer)
7 Mask sheet 7a Opening 11A 1st contact surface 11B 2nd contact surface 12 Connector 31 LED element 41, 41A, 41B Incidence surface 42, 42A, 42B Reflection surface 42a, 42Aa, 42Ba Reflection area | region 43, 43A, 43B Output surface 44A, 44B Side face 45, 45A, 45B End face

Claims (4)

An incident surface that faces in a direction perpendicular to the thickness direction that coincides with the emission direction, a reflection surface that is located behind the emission direction and has a reflection region in the shape of an image to be displayed, and front of the emission direction One or more light guide plates having an exit surface located at
One or more light sources located in front of the incident surface,
A display device configured to display an arbitrary image through the exit surface by reflecting light incident from the entrance surface forward in the exit direction by the reflection surface,
A light-reducing and transmitting layer that is positioned in front of the light guide plate in the emission direction and reduces the amount of light without changing the color temperature of the transmitted light;
A display device, comprising: a dark color surface that is located behind the light guide plate in the emission direction and reduces the amount of reflected light. First and second light guide plates laminated in the emission direction;
A first light source located in front of the entrance surface of the first light guide plate and a second light source located in front of the entrance surface of the second light guide plate;
A housing for housing the first and second light guide plates and the first and second light sources,
The end surface of the first light guide plate located on the side opposite to the entrance surface is more incident on the first light guide plate than the end surface of the second light guide plate located on the side opposite to the entrance surface in the emission direction. Away from the surface,
The case is in contact with the first light guide plate from the second light guide plate side, and is positioned between the end surface of the first light guide plate and the end surface of the second light guide plate in the emission direction view. The 1st contact surface which has a part to carry out, and the 2nd contact surface which contacts from the opposite side to the 1st light guide plate with respect to the 2nd light guide plate are formed. Display device.   The display device according to claim 2, wherein the end surface of the first light guide plate is inclined so as to be separated from the incident surface of the first light guide plate as the distance from the second light guide plate is increased in the emission direction. .   4. The display device according to claim 2, wherein a distance between the first contact surface and the second contact surface in the emission direction is larger than a thickness of the second light guide plate.