JP2002094119A - Indicating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an indicating device which is reduced in brightness variations and easy to adjust. SOLUTION: The indicator comprises an LED 2 ranked by the brightness variations, a current limiting resistor 9 connected in series to the LED 2, and a brightness adjusting resistor 12 which is ranked according to the rank of the LED and connected in parallel to the limiting resistor 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to a display device having LEDs.

[0002]

2. Description of the Related Art In a display device that performs display using an LED, there is a variation in the light emission luminance of the LED, and using it overlooking it will lead to a reduction in display quality of the display device. It is disclosed in Japanese Patent Application Laid-Open No. 8-152856.
It is shown to vary in the range of 33%.

In order to prevent the display quality from deteriorating due to such LED variations, different current limiting resistors are individually specified for each LED having a different brightness so that the brightness of the LED falls within a specified range. And connecting was commonly done.

[0004]

However, in the above configuration, the substitutability between LEDs having different luminances is poor, and when substituting, it is necessary to replace the corresponding current limiting resistor, and the circuit must be redesigned. Had a new problem of not being able to do so.

According to Japanese Unexamined Utility Model Publication No. 64-26789, a continuous variable resistor for adjusting brightness is connected in series with a fixed resistor for limiting current, a connector for wiring connection is provided on a rear surface, and rear connectors on both sides. By providing the mounting and fixing means so that it can be connected and connected, and by setting the variable resistance so that it can be adjusted from the rear surface even after fixing, it is possible to adjust the brightness of each LED by adjusting the continuous variable resistance. There is also known a configuration for performing the operation.

However, in such a configuration, there is a problem that the brightness of the LEDs must be adjusted one by one, and the adjustment work must be performed several times, which complicates the work.

Further, since the continuous variable resistor for adjusting the brightness is connected in series to the fixed resistor for limiting the current, even if an LED having a brightness within the specified range without any adjustment is installed, There is a problem that a circuit cannot be completed unless a continuous variable resistor that is unnecessary is connected.

The present invention solves these problems, and provides a display device with little variation in luminance and easy adjustment.

[0009]

In order to solve the above-mentioned problems, a display device according to the present invention is an LE device as described in claim 1.
D, a first resistor connected in series to the LED, and a second resistor connected in parallel with the first resistor.

According to a second aspect of the present invention, an LED ranked according to a variation in luminance, a current limiting resistor connected in series to the LED, and a current limiting resistor connected in parallel to the current limiting resistor, And a luminance adjusting resistor whose resistance value is determined according to the ranking.

[0011] This makes it possible to easily bring the brightness of the LED within the specified range by the combination of the ranked LEDs and the brightness adjusting resistors whose resistance values are determined correspondingly. Since the adjusting resistor is connected in parallel with the current limiting resistor, the circuit can be easily changed according to circumstances such as when replacing the LED or when there is no need for adjustment.

Further, in the first or second aspect, as described in the third aspect, a fixed resistor is provided as the brightness adjusting resistor.

[0013] This makes it possible to easily adjust the brightness of the LED to the specified standard by combining the ranked LED and the brightness adjusting resistor whose resistance value is determined correspondingly. Since the resistor is connected in parallel with the current limiting resistor, it is possible to easily change the circuit according to the situation such as when replacing the LED or when there is no need for adjustment, and use a fixed resistor By doing so, the adjustment work when using a continuous variable resistor is unnecessary, and the brightness adjustment of the LED becomes easy.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the accompanying drawings.

FIG. 1 shows an embodiment in which the display device of the present invention is used as a display device 1 for a vehicle. The display device 3 is provided above a display member 3 having a translucent display index 2 such as letters, numbers, and scales. Is a pointer 5 which is rotationally driven by an instrument body 4 located below the display member 3.
A predetermined display is performed in relation to the display index 2 depending on the position.

A light guide 6 for guiding light to the pointer 5 is provided on the rear surface of the display member 3. The pointer 5 is made to shine through the light guide 6, and light is transmitted to the back of the display member 3. An LED 7 that emits two white lights for illuminating the display index 2 by irradiating the LED is mounted on a circuit board 8 located behind the light guide 6.
The instrument body 4 is also arranged.

As shown in FIG. 2, the LED 7 has a current limiting resistor 11 and a current limiting resistor 11 between a power source (vehicle battery or a power supply circuit for adjusting the voltage from the vehicle battery) 9 and a ground (vehicle body) 10. It is arranged in series with the switch 12. When the switch 12 is turned on, the LED 7 emits light by the drive current adjusted by the current limiting resistor 11, and the light illuminates the display index 2 and the pointer 6 of the display member 3.

The LEDs 7 are classified into several ranks according to the difference in luminance. When the LEDs 7 having different ranks are arranged in the circuit shown in FIG. 2, the LEDs 7 are adjusted to have a luminance within a specified range. As shown in FIG.
A brightness adjustment fixed resistor 13 whose resistance value is determined so as to have a constant brightness by a combination with the rank of D7 is connected in parallel with the current limiting resistor 11.

By connecting the brightness adjusting fixed resistor 13 in parallel with the current limiting resistor 11, the driving current flowing through the LED 7 is adjusted, and the brightness of the LED 7 can be adjusted.

Further, since the resistance value of the fixed luminance adjusting resistor 13 is determined in advance in accordance with the ranking of the LEDs 7, the operation of adjusting the luminance becomes very easy. It is only necessary to select the corresponding brightness adjustment fixed resistor 13 and attach it to the circuit board 8 while checking the rank, and the brightness adjustment work becomes very easy.

Although the case where all the LEDs 7 have the same color has been described, the colors of light emission may be different.

Although the display device for a vehicle has been described as an example, the present invention is not limited to the above-described embodiment, and may be applied to a display device such as a clock.

[0023]

As described above, according to the display device of the present invention, the resistance value is determined in accordance with the LED and the rank of the LED according to the variation in luminance, and the LED is connected in parallel to the current limiting resistor. A display device that can easily adjust the brightness of the LED within a specified standard range can be realized by a combination of the brightness adjusting resistor and the resistor.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a display device for a vehicle according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an LED circuit before luminance adjustment in the LED lamp.

FIG. 3 is a circuit diagram showing an LED circuit after luminance adjustment in the LED lamp.

[Explanation of symbols]

 Reference Signs List 1 vehicle display device (display device) 2 display index 3 display member 4 instrument body 5 pointer 6 light guide 7 LED 8 circuit board 9 power supply 10 ground 11 current limiting resistor 12 switch 13 brightness adjustment fixed resistor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) G09G 3/32 G09G 3/32 A F term (Reference) 5C080 AA07 BB09 DD03 DD28 JJ03 JJ06 KK20 5C094 AA07 BA23 ED01 HA05 5C096 AA05 BA02 CA02 CB01 CC06 CC30 CD12 CD53 DC03 FA11 FA17 5F041 AA10 BB04 BB06 BB22 DC07 DC23 DC84 EE25 FF01

Claims (3)

[Claims] 1. A display device comprising: an LED; a first resistor connected in series to the LED; and a second resistor connected in parallel with the first resistor. 2. An LED ranked according to variation in luminance, a current limiting resistor connected in series to the LED, and a resistance value connected in parallel to the current limiting resistor and corresponding to the ranking. And a brightness adjustment resistor for which the following is determined. 3. The display device according to claim 1, wherein the brightness adjustment resistor includes a fixed resistor.