JP2012053182A - Display panel and diffusion sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display panel and a diffusion sheet, which can be inexpensively manufactured and can improve the visibility without being affected by the distance between the diffusion sheet and a substrate, and the directivity of a light emitting element.SOLUTION: A display panel 10 includes a substrate 4 mounting an LED 12, a housing 2 in which the substrate 4 is installed and a diffusion sheet 6 attached on the outer side of the front panel 2a of the housing 2 that has a hole 22 facing the LED 12. The diffusion sheet 6 has a protrusion part 32 protruding outward at a position in which the hole 22 of the housing 2 is closed.

Description

  Embodiments of the present invention relate to, for example, a display panel using an LED (light-emitting diode) as a light emitting element of an indicator lamp, and a diffusion sheet attached to the front side of the display panel.

  For example, in a display panel of a communication device, when an LED is used as a light emitting element of an indicator lamp for allowing an operator to recognize the operation state of a switch, a board on which the LED is mounted is disposed inside the display panel, and the front surface of the display panel A hole for emitting the light of the LED is formed in the housing on the side. And a diffusion sheet is affixed on the front surface of a display panel so that the hole of LED may be plugged up.

  The diffusion sheet functions to improve the visibility of the indicator lamp by the operator by diffusely reflecting and diffusing the light of the LED. In addition, in order to improve visibility, a light guide plate that equalizes the light intensity may be provided on the back side of the hole of the display panel.

  In addition to LEDs, other electronic components such as switching elements are also mounted on the substrate. For this reason, when the mounting height of other electronic components is higher than the mounting height of the LED, the distance between the housing of the display panel and the substrate becomes longer, and the distance between the LED and the diffusion sheet is also increased. End up.

  In general, when the distance between the light emitting element and the diffusion sheet is increased, the light emitted from the adjacent light emitting elements interferes with each other and the visibility decreases, or the intensity of the light emitted from the light emitting elements decreases and the light is visible. It may be worse.

  In order to eliminate such inconvenience, it is considered effective to use an LED having relatively strong directivity as a light emitting element.

Japanese Patent Laid-Open No. 2005-72396

  However, when an LED with strong directivity is used, the viewing angle of the lamp portion may be narrowed and visibility may be lowered only by providing a diffusion sheet. In order to prevent such a problem, a method of providing the above-described light guide plate for uniformizing the light of the LED is conceivable. However, the number of parts constituting the display panel increases, and the manufacturing cost increases.

  Therefore, it is desired to develop a display panel and a diffusion sheet that can be manufactured at low cost and have high visibility without being affected by the distance between the diffusion sheet and the substrate and the directivity of the light emitting element.

  The display panel according to the embodiment includes a substrate on which a light emitting element is mounted, a housing in which the substrate is attached on the inside, and a diffusion sheet attached on the outside of the housing. The housing has a hole facing the light emitting element. The diffusion sheet has a protrusion protruding outward at a position where the hole of the housing is closed.

FIG. 1 is an exploded perspective view illustrating a display panel according to an embodiment. FIG. 2 is a front view of the display panel of FIG. 3 is a cross-sectional view of the display panel taken along line III-III in FIG. FIG. 4 is a partial enlarged cross-sectional view showing a main part of FIG. 3 partially enlarged. FIG. 5 is a partially enlarged cross-sectional view showing a state in which the substrate of FIG. 4 and the diffusion sheet are brought close to each other. FIG. 6 is a partially enlarged cross-sectional view showing a state where the substrate and the diffusion sheet of FIG. 4 are separated from each other. FIG. 7 is a partially enlarged cross-sectional view showing another embodiment in which a resin is filled inside the protrusion of the diffusion sheet of FIG.

Hereinafter, embodiments will be described in detail with reference to the drawings.
FIG. 1 is an exploded perspective view of a display panel 10 according to the embodiment. FIG. 2 is a front view of the display panel 10 as viewed from the operator side. 3 shows a cross-sectional view of the display panel 10 taken along line III-III in FIG. Further, FIG. 4 shows a partially enlarged cross-sectional view in which the main part of FIG. 3 is partially enlarged.

  The display panel 10 includes a substantially rectangular box-like case 2 (housing) whose back side is open, a rectangular plate-like substrate 4 attached to the back side of the front panel 2 a of the case 2, and a front panel 2 a of the case 2. And a rectangular diffusion sheet 6 attached to the surface. The substrate 4 is slightly smaller than the front panel 2 a of the case 2, and the diffusion sheet 6 has a size that is slightly smaller than the substrate 4.

  A plurality of LEDs 12 (light emitting elements) are mounted on the front surface 4a (mounting surface 4a) of the substrate 4 opposite to the back surface of the case 2 as a light source of the indicator lamp. A wiring pattern (not shown) is formed. In addition, a plurality of push button switches 14 are mounted on the mounting surface 4 a of the substrate 4. Furthermore, a monitor device 16 for displaying various types of information to the operator is mounted on the mounting surface 4a of the substrate 4. In addition, a plurality of types of electronic components (not shown) are mounted on the mounting surface 4 a of the substrate 4. In the present embodiment, seven LEDs 12, four push button switches 14, and one monitor device 16 are attached to the surface 4 a of the substrate 4.

  In addition, a plurality (seven in this embodiment) of circular holes 22 respectively facing the plurality of LEDs 12 described above are formed on the front panel 2a of the case 2 that is disposed so as to be opposed to the mounting surface 4a of the substrate 4. A plurality of (four in this embodiment) circular holes 24 respectively opposed to the plurality of push button switches 14 and a rectangular shape for exposing the monitor device 16 to the surface side of the case 2. Holes 26 are formed through the front panel 2a. A plurality of boss portions 28 (FIG. 3) for fastening and fixing the substrate 4 are integrally projected on the back surface side of the case 2 where the front panel 2a faces the substrate 4.

  Further, the diffusion sheet 6 attached to the surface of the front panel 2 a of the case 2 also has a rectangular hole 31 for exposing the monitor device 16. The diffusion sheet 6 is formed of a translucent resin material, and has a function of diffusely reflecting and diffusing transmitted light. For example, the diffusion sheet 6 of this embodiment is made translucent by mat processing.

  The diffusion sheet 6 has substantially hemispherical protrusions 32 that transmit and diffuse light emitted from the LEDs 12 at positions facing the plurality of LED holes 22 provided in the case 2. . As shown in FIGS. 3 and 4, each protrusion 32 is formed by projecting a part of the diffusion sheet 6 forward in a hemispherical shape toward the light emission direction, that is, the operator viewing the display panel 10. In addition, in order to form these some protrusion 32, the diffusion sheet 6 is formed by hot press processing, for example.

  Further, the diffusion sheet 6 has circular windows 34 for pressing the push button switch 14 at positions facing the plurality of switch holes 24 provided in the case 2. As shown in FIG. 2, for example, “SW” is printed on each window 34. In addition, on the surface of the diffusion sheet 6, characters 36 and a frame 38 indicating the type of each LED indicator are printed.

  As shown in FIGS. 3 and 4, a plurality of LEDs 12 and a plurality of push button switches 14 (only one is shown here) are mounted on the mounting surface 4 a of the substrate 4. In the present embodiment, the mounting height of the push button switch 14 is higher than the mounting height of the LED 12. The substrate 4 is fastened and fixed to the boss portion 28 projecting from the back surface of the panel 2a with a screw 29 with the mounting surface 4a facing the back surface of the front panel 2a of the case 2. At this time, the gap between the mounting surface 4a of the substrate 4 and the back surface of the front panel 2a of the case 2 is at least larger than the mounting height of all the electronic components mounted on the substrate 4, and the electronic components are There is no contact with the back side.

  As shown in FIG. 4, in the present embodiment, the height of the push button switch 14 is substantially in contact with the back surface of the window portion 34 of the diffusion sheet 6 through the hole 24 formed in the front panel 2 a of the case 2. It is growing. Accordingly, the push button switch 14 can be switched only by the operator pressing the window 34 of the diffusion sheet 6 slightly.

  Here, with reference to FIG. 5 and FIG. 6, the effect | action and effect of the protrusion 32 of the diffusion sheet 6 mentioned above are demonstrated. FIG. 5 shows a state in which the substrate 4 is brought close to the front panel 2 and the LED 12 is brought close to the diffusion sheet 6. In FIG. 6, the substrate 4 is separated from the front panel 2 and the LED 12 and the diffusion sheet 6 are separated from each other. The state is shown. For example, when the push button switch 14 or the like having a relatively high mounting height is not mounted on the mounting surface 4a of the substrate 4, the substrate 4 and the front panel 2a of the case 2 can be brought close to each other as shown in FIG. 6 corresponds to FIG. 3 and FIG.

  In general, the LED 12 has high directivity and does not spread light. Therefore, even if the substrate 4 and the diffusion sheet 6 are close to the extent shown in FIG. 5 or apart as shown in FIG. 6, most of the light emitted from the LEDs 12 passes through the holes 22 in the front panel 2a. The projection 32 is passed through. Then, the light passing through the protrusion 32 is diffused by being diffusely reflected and diffused by the portion 32 of the diffusion sheet 6 whose area is expanded in a hemispherical shape, and makes the entire protrusion 32 shine. That is, according to the present embodiment, in addition to the use of the diffusion sheet 6, the LED 12 is used as the light emitting element, so that the protrusion 32 emits almost the same light regardless of the distance between the LED 12 and the diffusion sheet 6. Can be.

  Moreover, since the protrusion 32 protrudes to the front side of the display panel 10, the light diffused so as to shine the entire protrusion can be viewed with a relatively wide viewing angle α. In other words, according to the present embodiment, in addition to using the diffusion sheet 6, the projection 32 is formed by partially projecting the portion of the diffusion sheet 6 facing the LED 12 forward, so that the wide field of view of the indicator lamp A corner can be secured and visibility can be improved.

  In particular, according to the present embodiment, even when there is a slight misalignment along the surface direction between the substrate 4 and the front panel 2a, the visibility of the LED indicator lamp does not deteriorate. Further, even when the LED 12 is mounted in a state tilted with respect to the mounting surface 4a of the substrate 4, the visibility of the LED indicator lamp does not deteriorate. That is, according to this embodiment, if the axis of the light emitted from the LED 12 passes through any part of the protrusion 32, the entire protrusion 32 can be illuminated, so that the light transmission position is the center of the protrusion 32. Even if slightly deviated from the above, the light emission intensity of the indicator lamp does not decrease significantly, and the visibility does not decrease. For this reason, according to this embodiment, there is no need to make the mounting orientation of the LED 12 with respect to the substrate 4 with a high degree of accuracy perpendicular to the mounting surface 4a, and the mounting position of the substrate 4 is also highly accurate with respect to the case 2 in the surface direction. There is no need to align. For this reason, the assembly accuracy of the display panel 10 can be lowered, and the manufacturing cost can be reduced.

  Moreover, as a matter of course, according to the present embodiment, compared to the case where the flat diffusion sheet 6 is opposed to the LED 12 without providing the protrusion 32, a part of the diffusion sheet 6 is formed forward as the protrusion 32. Since it protruded, the area which shines by that much and the part which protruded ahead from the surface of the diffusion sheet 6 shines, Therefore Visibility can also be improved. In particular, according to the present embodiment, even when the light emission intensity of each LED 12 decreases with time, the degree of visibility deterioration is low because the light emission area of the protrusion 32 is large.

  In addition, according to the present embodiment, the brightness of the display lamp can be made uniform even if there is a variation in brightness due to a difference between individual LEDs among the plurality of LEDs 12 due to the action of the diffusion sheet 6 and the protrusion 32. Variations in height can be compensated. Thereby, the malfunction which an operator misrecognizes the lighting state of an indicator lamp can be prevented, and the reliability as the display panel 10 can be improved.

  Furthermore, according to the present embodiment, since the protrusion 32 of the diffusion sheet 6 can be formed by hot pressing with a mold, an expensive apparatus is not required, the manufacturing can be facilitated, and the manufacturing cost of the diffusion sheet 6 can be reduced.

  FIG. 7 is a partial enlarged cross-sectional view in which a structure of a main part of a display panel according to another embodiment is partially enlarged. The structure of this embodiment is the same as that of the above-described embodiment except that the resin 8 is filled inside the protrusion 32 of the diffusion sheet 6. Therefore, the same reference numerals are given to components that function in the same manner as in the above-described embodiment, and detailed description thereof will be omitted.

  The resin 8 is filled with a transparent resin material inside the protrusion 32 and hardened. For this reason, the diffusion sheet 6 filled with the resin 8 on the inside of the protrusion 32 has high mechanical strength at the resin 8 portion. For example, the protrusion 32 is not recessed even if the protrusion 32 is pressed from the surface of the diffusion sheet 6. Can be reinforced. In addition, since the structure of this embodiment is a change which only fills the resin 8 inside the protrusion 32 compared with embodiment mentioned above, the manufacturing cost of the diffusion sheet 6 does not increase significantly. .

  Further, as in this embodiment, by filling the resin 8 inside the protrusion 32, the resin 8 can function as a light guide plate, and the light emitted from the LED 12 can be more effectively transferred to the diffusion sheet 6. It can be communicated, and the visibility can be further improved. That is, the light incident on the resin 8 spreads over the entire protrusion 32 due to the lens effect, and the entire protrusion 32 can be illuminated without any spots.

  Furthermore, the resin 8 can be colored in a desired color. In this case, for example, all the LEDs 12 used in the display panel 10 may emit white light, and the color of the resin 8 filled in each protrusion 32 of the diffusion sheet 6 may be a desired color. Thereby, it is not necessary to prepare the LEDs 12 of the respective colors and attach them at predetermined positions, and the color combinations can be freely made only by replacing the diffusion sheet 6. That is, it is not necessary to manage and store the LEDs 12 of a plurality of colors, and the operation cost can be reduced. In this case, the plurality of display lamps of the display panel 10 can be easily set to an arbitrary color, so that erroneous recognition of the display lamp by the operator can be reduced, and reliability can be improved.

  As described above, according to the above-described embodiment, the display panel 10 that can be manufactured at low cost and has high visibility without being influenced by the distance between the diffusion sheet 6 and the substrate 4 or the directivity of the LED 12 and the like. The diffusion sheet 6 can be provided.

  As mentioned above, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, in the above-described embodiment, the case where the LED 12 is used as the light emitting element has been described. However, the present invention is not limited thereto, and other light emitting elements such as a light bulb and an organic EL may be used in addition to various LEDs.

  DESCRIPTION OF SYMBOLS 2 ... Case, 2a ... Front panel, 4 ... Board | substrate, 4a ... Mounting surface, 6 ... Diffusion sheet, 8 ... Resin, 10 ... Display panel, 12 ... LED, 22 ... Hole, 32 ... Projection part.

Claims (9)

A light emitting element;
A substrate on which the light emitting element is mounted;
A diffusion sheet disposed opposite to the mounting surface of the substrate, and
The said diffusion sheet is a display panel which has the protrusion which protruded in the light emission direction in the site | part which the light inject | emitted from the said light emitting element permeate | transmits.   The display panel according to claim 1, wherein a transparent resin is filled inside the protrusion.   The display panel according to claim 2, wherein the resin is colored. A light emitting element;
A substrate on which the light emitting element is mounted;
A housing having a hole opposed to the light emitting element and disposed opposite to the mounting surface of the substrate;
A diffusion sheet that is attached to a surface of the housing that is separated from the substrate and has a protrusion that protrudes in the light emission direction facing the hole;
A display panel.   The display panel according to claim 4, wherein a transparent resin is filled inside the protrusion.   The display panel according to claim 5, wherein the resin is colored.   A diffusion sheet, which is disposed so as to be spaced apart and opposed to a mounting surface of a substrate on which a light emitting element is mounted, and has a protrusion protruding in the light emitting direction at a portion through which light emitted from the light emitting element is transmitted.   The diffusion sheet according to claim 7, wherein a transparent resin is filled inside the protrusion.   The diffusion sheet according to claim 8, wherein the resin is colored.

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