JPH0753101Y2 - LED surface illumination display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a display device having a surface illumination display function such as an indicator lamp used for a display panel such as a control panel and an illumination switch.

(B) Conventional Technology In a display device used for a display panel such as a control panel, light from an internal light source is radiated to the outside through a translucent filter or a cover, thereby displaying the state of the control device. There is something I did. In addition, there is an illumination switch or the like in which an operation content is written on a translucent cover and is displayed on the surface by the light of an internal light source. In such a display device, the light amount of the light source may need to be changed in order to display the change in the state of the control device or in consideration of the illuminance of another display device. The light amount of the light source is changed by changing the limiting resistance value by the volume or by changing the power supply voltage itself to change the voltage value applied to the light source.

(C) Problems to be Solved by the Invention However, when the voltage value applied to the light source is changed and dimming is performed as in the above-described conventional display device, the volume and the transformer are installed inside the operation panel, so that the display is performed once. When the light amount of the device is set, it has a drawback that it cannot be easily changed thereafter. Further, the volume and the transformer generally require manual operation, and if the conventional display device is to automatically adjust the light amount, a driving means such as a motor is required, which leads to an increase in size of the device. For these reasons, the conventional display device cannot easily change the light amount according to the state of the control device.

The purpose of this invention is to change the number of LEDs to be turned on among a plurality of LEDs provided in the case by using a decoder so that the number of LEDs to be turned on can be changed based on the code data of the control shell. An object of the present invention is to provide an LED surface illumination display device that can easily change the light amount.

(D) Means for Solving the Problems The LED surface illumination display device of the present invention is provided at a position where a case having a light diffusion filter on the surface thereof and a light diffusion filter within the case all directly face each other. Provided with a plurality of LEDs that compose a 7-segment LED display for displaying Japanese character type numerical values, and a BCD TO 7-segment decoder that drives the LED corresponding to the drive data of the input BCD code among the plurality of LEDs. The light diffusing filter has a diffusing characteristic that the brightness is always uniform regardless of the number displayed on the 7-segment LED display.

(E) Operation In the present invention, among the plurality of LEDs constituting the 7-segment LED display, the predetermined LED set by the drive data of the BCD code is driven by the BCD TO 7-segment decoder. The configuration and number of LEDs driven in the 7-segment LED display differ depending on the numerical value to be displayed, and the numerical value to be displayed is specified by the BCD code.

Further, the light of the turned-on LED passes through the light diffusion filter and is distributed to the outside. This light diffusion filter has 7 segments
It has the diffusion characteristic that the brightness is always uniform regardless of the number displayed on the LED display. All LEDs are facing the same area of the light diffusion filter and drive
If the number of LEDs changes, the amount of light emitted to the above range changes.

Therefore, BC input to BCD TO 7 segment decoder
The number of LEDs that light up changes according to the D code, and the amount of surface illumination generated by the light diffusion filter on the surface of the case changes. At this time, due to the diffusion characteristics of the light diffusion filter, even if the number and position of the LEDs to be lit change, such as when the numbers displayed on the 7-segment LED display are 1 and 8, the entire surface of the filter is changed. Just changing the brightness
LED light source image does not occur.

(F) Embodiment FIG. 2 is a partial sectional view of a side surface of an illuminated push button switch which is an LED surface illuminated display device according to an embodiment of the present invention.

A cover 2 is provided on a surface (operation side) 1a of a main body 1 of an illuminated push button switch which is resin-molded in a hollow shape. The cover 2 is made of polyarylate resin and has translucency. The cover 2 is biased in the direction of arrow N by a spring (not shown), and moves in the direction of arrow M when pressed from the front side. LED on the inner surface of cover 2
The display 3 faces. The terminal 3a of the LED display 3 is connected to the decoder 4 via the printed board 3b. A micro switch 5 is provided below the inside of the main body 1. Actuator 5a of this micro switch 5
The operation of the cover 2 is transmitted to the actuator 5a via the pressing member 6, and when the cover 2 is pressed in the direction of arrow M, the actuator 5a
Presses the protrusion 5b to turn on the microswitch 5.
The micro switch 5 includes the flexible printed circuit board 7 and the flexible printed circuit board 7 together with the decoder 4.
It is connected to an external substrate (not shown) through a connector 9 fixed by a reinforcing plate 8.

3A to 3C are a half cross-sectional view of a plane, a half cross-sectional view of a side surface, and a half cross-sectional view of a front surface of an LED display included in the above-mentioned LED surface illumination display device.

A light diffusion filter 13 is provided on the surface of a case 18 resin-molded in a hollow box shape. Further, inside the case 18, the LED chip 11 is attached on the substrate 12 so as to face the inner surface of the light diffusion filter 13. This LED
The display 3 is a commercially available 4-digit LED display for displaying numbers, and the filter for displaying numbers is replaced with a light diffusion filter. In this LED display 3, one digit consists of 7-segment LED, total 28 LED chips.
Equipped with 11. The inner surface of the light diffusion filter 13 is roughened and made semitransparent, the LED chip 11 is not directly visible, and the light diffusion filter 13 emits light with a substantially uniform brightness over a wide range. That is, the outer surface of the light diffusion filter 13 is turned on.
The light source image of LED11 does not occur. This is because even if the number and distribution of the LEDs 11 that are turned on by the light diffusion filter 13 when displaying 1 and 8 in the day character are largely changed, the lightness is uniform over the entire surface of the filter 13. This is because it has the following diffusion characteristics.

FIG. 1 is a schematic circuit diagram of the LED surface illumination display device.

In the LED display 3, the LED chip 11 is provided on the substrate 12 at a position that constitutes a date character. The date character shown by the alternate long and short dash line in the figure is composed of a filter for displaying numbers, and in this embodiment, the date character is not displayed because it is replaced with the light diffusion filter as described above. Each of the 7-segment LED chips 11 is connected to each of the output terminals A to G of the decoder 4 which is a BCD TO 7-segment decoder IC. LEDs of each digit are connected to the output terminals A to G of the decoder 4 in the same state. Further, all the common terminals of each digit indicated by the chain double-dashed line in the figure are grounded.
Further, drive data by BCD code is input to the input terminals 4a to 4d of the decoder 4 from a control unit (not shown). A commercially available decoder for driving a 7-segment LED display can be used as the decoder 4.

According to the present embodiment having the above-described configuration, the LEs at the same position in each digit according to the drive data input to the decoder 4
D-chip lights up. The drive data input to the decoder 4 and the states of the output terminals A to G of the decoder 4 have the relationship shown in FIG. 4, and for example, the drive data "000" indicating "0" is displayed.
When 0 "is input to the decoder 4, the LED segments 11a-11
Six LED chips of f light up. This is the same for each digit, so overall 24 LED chips are illuminated. When the drive data "0001" indicating "1" is input, the two LED chips of the LED segments 11b and 11c are turned on at each digit, and eight LEDs are turned on as a whole.

As is clear from FIG. 4, 2,3,4,5,6,7 LEDs are arranged at each digit according to the driving data input to the decoder 4.
Seven types of lighting states are realized, including a non-lighting state in which each chip lights up and all 7-segment LED chips are turned off. In the light diffusion filter 13 facing all 28 LED chips 11, the amount of surface illumination is approximately proportional to the number of LED chips that are turned on. Therefore, the surface illumination of the light diffusion filter is input according to the drive data input to the decoder 4. The amount of light can be changed in 7 steps. Moreover, since the same number of LED chips always light up in each digit, the light diffusion filter 13
The amount of light can be changed uniformly over the entire surface. Furthermore, a commercially available LED display and a similarly commercially available decoder for driving the same can be used, and can be manufactured at low cost.

FIG. 5 is a plan view showing another embodiment of the present invention.

As shown in FIG.
Divided into the above plurality of portions 21a, 21b, and by providing a separate decoder for each of the divided LED displays belonging to each of the divided ranges, it is different at a plurality of locations on the surface of a single light diffusion filter It is possible to generate surface illumination of a light amount and perform divided light distribution.

The LED display used in the embodiment of the present invention is not limited to the LED display for displaying 4-digit numbers, and a large number of LEDs arranged in other shapes may be used. Further, the present invention can be similarly applied to a display device other than the illuminated push button switch. Further, although the decoder is provided in the display device main body in the present embodiment, it may be provided on the external substrate.

(G) Effect of the Invention According to this invention, a plurality of LEs facing the light diffusion filter are provided.
Of D, by turning on the LED that constitutes the number corresponding to the BCD code input to the BCD TO 7-segment decoder, you can easily change the amount of surface illumination of the light diffusion filter according to the BCD code. The light quantity of the display device such as the illumination switch can be easily changed, and the display content on the display device can be easily emphasized by the bright and dark display according to the operation state or the state of the control device.

In addition, commercially available LED display and decoder IC for numerical display
Since it can be used, compatibility with other products can be achieved, cost reduction can be realized, parts management, etc. can be facilitated, and it is necessary to newly design the drive circuit configuration and drive data. There is no advantage, and there is an advantage that the work load at the design stage can be remarkably reduced.

[Brief description of drawings]

FIG. 1 is a schematic circuit diagram of an LED surface illumination display device according to an embodiment of the present invention, and FIG. 2 is a partial side sectional view showing a configuration of an illumination push button switch which is the LED surface illumination display device,
3 (A) to 3 (C) are a plane half cross-sectional view, a side half cross-sectional view, and a front half cross-sectional view of the LED surface illumination display device, respectively.
Fig. 4 shows the drive data and LEDs in the LED surface illumination display device.
It is a figure which shows the relationship with the lighting number of. FIG. 5 is a plan view showing an LED surface illumination display device according to another embodiment of the present invention. 3-LED display, 4-decoder, 11-LED chip, 13-light diffusion filter.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yuya Kawai Inventor Yuya Kawai 1-3-14 Nishi-Shinjuku, Shinjuku-ku, Tokyo (Heiwa Building) Takamizawa Cybernetics Co., Ltd. (56) Reference JP-A-52-146591 ( JP, A) JP 53-32624 (JP, A) JP 63-70283 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A case having a light diffusion filter on a surface thereof,
Multiple LEDs that compose a 7-segment LED display for day character type numeral display, which are provided in positions that directly face each other in the same area of the light diffusion filter in the case, and multiple LEDs
LED corresponding to the input BCD code drive data
And a BCD TO 7-segment decoder for driving the light-diffusing filter, wherein the light-diffusing filter has a diffusion characteristic in which the brightness is always uniform regardless of the number displayed on the 7-segment LED display. .