JPH0869879A - Brightness correcting device of light emitting pointer - Google Patents

Abstract

PURPOSE: To keep light emitting brightness of an EL painter constant by using a brightness correcting circuit while enabling installation of a sensor to detect the light emitting brightness of the rotating EL pointer. CONSTITUTION: A photosensor 3 to detect light emitting brightness of an EL pointer 1 is installed in a position opposed to a light emitting part 1a of the EL pointer 1 on an inside surface of a painter cap 15 to be pressed in and fitted to the tip of a movement shaft 7. The photosensor 3 can always detect the light emitting brightness even if the EL painter 1 rotates, and keeps the light emitting brightness of the EL pointer constant by a brightness correcting circuit according to a detecting value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brightness correction device for a light emitting pointer which emits light when a voltage is applied.

[0002]

2. Description of the Related Art As a light emitting pointer used for a speedometer or the like in a vehicle instrument, for example, there is one using electroluminescence (hereinafter referred to as EL). EL refers to a phenomenon in which a phosphor emits light when an AC electric field (which may be DC) is applied to the phosphor such as zinc sulfide (ZnS). The emission brightness due to this EL depends on the voltage and frequency of the applied AC electric field, and basically increases as these values increase.

According to the voltage-luminance characteristic diagram of FIG. 6, when the voltage is gradually increased, the EL starts to emit light at the time when the voltage reaches a certain voltage V ₁ , and then the luminance also increases as the voltage rises. According to the frequency-luminance characteristic of FIG. 7, basically, the luminance increases with the increase of the frequency, and gradually shows a tendency of saturation. The brightness increases with increasing frequency, EL is 1H
This is because light is emitted twice per z, and the frequency of light emission increases as the frequency becomes higher.

Under such a characteristic, the EL is set to a predetermined luminance in advance by adjusting the voltage and the frequency. On the other hand, the EL is indicated by the solid line in the drive time-luminance characteristic diagram of FIG. In addition, there is a problem in that the brightness deteriorates as the driving time elapses, and the initially set brightness cannot be maintained.

In order to solve this problem, Japanese Patent Laid-Open No. 3-208
As typified by Japanese Patent Publication No. 296, a method in which a photosensor detects the light emission luminance of an EL, and the voltage or frequency applied to the EL is adjusted based on the electric signal obtained thereby to keep the luminance constant. Is being considered.

[0006]

However, in the above-mentioned technique, the method of installing the photosensor for detecting the brightness of the EL is not particularly considered, or E
It seems that L is considered only when it is used as a fixed back light for a personal computer or a watch, and when it rotates like a pointer, special consideration should be given to the installation of the photo sensor. is there.

Therefore, an object of the present invention is to make it possible to install a sensor for detecting the light emission brightness of a rotating pointer and to keep the light emission brightness of the pointer constant by using a brightness correction circuit. .

[0008]

In order to achieve the above object, the present invention provides a light emitting pointer which emits light when a voltage is applied, and a rotatable movement in which the base end side of the light emitting pointer is fixed to the tip. The shaft, a pointer cap fixed to the tip of the movement shaft so as to cover the fixed portion of the movement shaft and the light emitting pointer, and attached to a position facing the light emitting portion of the light emitting pointer in the pointer cap, It is configured to have a brightness detecting sensor that detects the brightness of the light emitting pointer and a brightness correction circuit that adjusts the brightness of the light emitting pointer according to the detection value of the brightness detecting sensor.

In the above-mentioned light emitting pointer, an electrode core material is provided in the central portion and a transparent electrode layer is provided in the outer peripheral portion, and the movement shaft has an insulating layer interposed between the inner shaft and the outer shaft, and the inner shaft. Is made of a conductive material having a double structure protruding from the tip of the outer shaft, and the inner shaft serves as a ground electrode, and the electrode core material of the light emitting pointer is electrically connected to the protruding end of the inner shaft from the outer shaft. At the same time, the electrodes are connected to one electrode terminal of the brightness detecting sensor, and one of the transparent electrode layer of the light emitting pointer and the other electrode terminal of the brightness detecting sensor is connected to the outer shaft. The other may be attached to the outer peripheral side of the outer shaft via an insulating layer and may be connected to a return spring made of a conductive material for returning the movement shaft.

The above-mentioned brightness detecting sensor is fixed to the inner surface of the pointer cap with an adhesive, and by this adhesive, the inner shaft of the movement shaft, the electrode core material of the light emitting pointer and one electrode terminal of the brightness detecting sensor. Is fixed.

In the above-mentioned light emitting pointer, an electrode core material is provided in the central portion and a transparent electrode layer is provided in the outer peripheral portion, and the movement shaft has an insulating layer interposed between the inner shaft and the outer shaft, and the inner shaft. Is made of a conductive material having a double structure protruding from the tip of the outer shaft, and is attached to the outer peripheral side of the outer shaft via an insulating layer and is made of a conductive material for returning the movement shaft. As a ground electrode, the lead spring connected to the electrode core material of the light emitting pointer is connected to the return spring, and at the same time, one electrode terminal of the brightness detection sensor is connected to the end of the inner shaft protruding from the outer shaft. A transparent electrode layer of the light emitting pointer or a conductive layer portion conducting to the transparent electrode layer may be electrically connected and fixed to the portion, and the other electrode terminal of the brightness detection sensor may be connected to the outer shaft. .

In the above-mentioned light emitting pointer, an electrode core material is provided in the central portion and a transparent electrode layer is provided in the outer peripheral portion, and the movement shaft has an insulating layer interposed between the inner shaft and the outer shaft, and the inner shaft. Is made of a conductive material having a double structure protruding from the tip of the outer shaft, and the outer shaft is used as a ground electrode, and at the same time when the electrode core material of the light emitting pointer is connected via a lead wire, Connect one electrode terminal of the brightness detection sensor,
The transparent electrode layer of the light emitting pointer or a conductive layer portion electrically connected to the transparent electrode layer is electrically connected to and fixed to the end of the inner shaft protruding from the outer shaft, and the other electrode terminal of the brightness detection sensor is fixed. It may be configured to be connected to a return spring made of a conductive material for returning the movement shaft.

The brightness detecting sensor is fixed to the inner surface of the pointer cap with an adhesive, and by this adhesive, the inner axis of the movement shaft and the transparent electrode layer of the light emitting pointer or a conductive layer portion conducting to the transparent electrode layer. Is fixed.

Auxiliary return springs made of a conductive material for assisting the return force of the return spring are attached to the outer peripheral surfaces of the ends of the inner shaft and the outer shaft opposite to the light emitting pointers, and the return spring and the auxiliary return spring are lit. It may be connected to the correction circuit.

The auxiliary return springs attached to the inner shaft and the outer shaft may be arranged such that the winding directions are opposite to each other and the biasing forces are equal.

[0016]

According to the brightness correction device for the light emitting pointer having such a structure, the brightness detecting sensor provided in the pointer cap moves together with the movement of the movement shaft and the light emitting pointer, and the light emitting pointer rotates. Even if it is in the state of being operated, the brightness of the light emitting pointer is accurately detected, and the brightness of the light emitting pointer is kept constant by the brightness correction circuit based on the detected value.

Further, the movement shaft has a dual structure of an inner shaft and an outer shaft, and each of the inner and outer shafts and the return spring are used as an electrode lead-out portion to connect the light emitting pointer and each electrode terminal of the luminance detecting sensor. In addition, since the ground electrode can be shared by the light emitting pointer and the brightness detecting sensor by using the inner electrode, the outer shaft, or the return spring as the ground electrode, the number of electrode extraction portions can be reduced and the structure can be simplified.

By fixing the brightness detecting sensor to the inner surface of the pointer cap using an adhesive,
The inner shaft of the movement shaft, the electrode core material of the light emitting pointer, and one electrode terminal of the brightness detection sensor are simultaneously fixed. Also, with the adhesive for fixing the brightness detection sensor to the inner surface of the pointer cap, the inner shaft of the movement shaft,
The transparent electrode layer of the light emitting pointer or the conductive layer portion that is electrically connected to the transparent electrode layer is fixed at the same time.

Since the auxiliary return springs attached to the inner shaft and the outer shaft can be used as the electrode extracting portion,
It becomes easy to draw a lead wire from the rotating movement axis to the brightness correction circuit. Also, by making the biasing forces of the two auxiliary return springs equal and reversing the winding direction, the rotational force applied to the movement shaft by the auxiliary return springs is offset, and the biasing force of the auxiliary return springs is particularly taken into consideration. No need.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 relates to a first embodiment of the present invention, which is an EL (electroluminescence) pointer 1 which is a light emitting pointer, and a photosensor (a brightness detecting sensor for detecting the light emission brightness of the EL pointer 1). FIG. 3 is a schematic exploded perspective view showing a connection state of respective electrodes of cds) 3.

The EL pointer 1 is used as a pointer for a speedometer, a tachometer, etc. in a vehicle instrument, and has a porcelain insulating reflection layer around the electrode core material 5 made of stainless steel and a phosphor dispersed in the enamel. The phosphor layer, the transparent electrode layer and the transparent protective layer thus formed are sequentially laminated. By electrically connecting and energizing the electrode core material 5 and the transparent electrode layer, an electric field is applied to the phosphor layer, and the phosphor emits light.

The end portion of the electrode core material 5 of the EL pointer 1 on the base end side is exposed to the outside, and the exposed portion is fixed to the tip of the movement shaft 7. The movement shaft 7 includes a magnet rotor (not shown), and is rotatably supported by a coil bobbin around which a pair of coils that generate mutually orthogonal magnetic fields are wound, and a current that changes according to the measured amount is passed through the coil. To rotate. The movement shaft 7 is made of a conductive material and is composed of an inner shaft 9 and an outer shaft 11 fixed around the inner shaft 9 via an insulating layer (not shown). Side and the base end side of the lower part respectively protrude from the outer shaft 11.

A U-shaped notch 13 is formed on the upper end side of the inner shaft 9 in the figure.
The electrode core material 5 of the pointer 1 is inserted and fixed by caulking or the like. A pointer cap 15 is attached around the fixed portion. FIG. 2 shows how the pointer cap 15 is attached to the fixed portion. The pointer cap 15 has an inverted cup shape as a whole, and the inner surface of the pointer cap 15 has a central boss portion 17,
A fitting hole 19 into which the tip of the inner shaft 9 of the movement shaft 7 is press-fitted, and an insertion groove 2 into which the electrode core material 5 of the EL pointer 1 is inserted.
1 and 1 respectively, and a notch 23 through which the light emitting portion 1a of the EL pointer 1 is inserted is formed on the side wall on the outer peripheral side. By pressing the tip of the inner shaft 9 into the fitting hole 19 while the EL pointer 1 is fixed to the movement shaft 7, the pointer cap 15 is fixed to the EL pointer 1 side.

Light emitting part 1 of EL pointer 1 of pointer cap 15
The photo sensor 3 described above is fixed to the inner surface facing a by the hook 25. As shown in FIG. 1, one of the electrode terminals of the photosensor 3 is connected by soldering to the inner shaft 9 of the movement shaft 7 using the inner shaft 9 as a ground electrode via a lead wire 27, and the other electrode terminal is Lead wire 2
A return spring 33, one end of which is fixed to the outer circumference of the outer shaft 11 via an insulating tape 31, is connected by soldering. The return spring 33 is for returning the pointer display by the EL pointer 1 so that the pointer display by the EL pointer 1 is zeroed in a state where the rotational force by the magnetic field generated by the coil is not applied to the movement shaft 7, and the other end side rotates the movement shaft 7. It is fixed to a coil bobbin (not shown) that supports and is made of a conductive material.

Enameled wire 3 is provided on the transparent electrode layer of EL pointer 1.
The end of the enamel wire 35 wound around the transparent electrode layer 5 is connected to the outer shaft 11 of the movement shaft 7 by soldering. The electrode core material 5 of the EL pointer 1 is
It is electrically connected to the inner shaft 9 by being fixed to the upper end of the inner shaft 9 serving as a ground electrode.

Around the end of the movement shaft 7 opposite to the EL pointer 1, one ends of auxiliary return springs 37 and 39 made of a conductive material are wound.
The other ends of the auxiliary return springs 37 and 39 are fixed to the coil bobbin like the return spring 33 described above. Each of the auxiliary return springs 37 and 39 has the same winding direction as the litter spring 33, and has a role of assisting the restoring force of the litter spring 33. Therefore, by adjusting the biasing forces of the litter spring 33 and the auxiliary return springs 37, 39, it becomes possible to adjust the restoring force of the movement shaft 7. For example, if the material and the wire diameter are the same, the number of turns may be changed.

The EL pointer 1 and the retarder spring 33 and auxiliary return springs 37 and 39, which serve as electrode extraction portions of the photosensor 3, are connected to a brightness correction circuit shown in FIG. The brightness correction circuit adjusts the brightness of the EL pointer 1 according to the detection value of the photo sensor 3 to keep it constant.
The circuit configuration will be described with reference to FIG.

Return spring 33 of photosensor 3
The electrode terminal (lead wire 29) connected to is connected to the + side input terminal of the comparator 41 together with the resistor R _ref connected to the DC power supply voltage V _T , and the voltage input to this + side input terminal. V _ref is the photo sensor 3 and the resistance R
Determined by the ratio of the resistance value to _ref . On the other hand, EL pointer 1
The electrode terminal (the enamel wire 35) connected to the auxiliary return spring 37 of the above through the outer shaft 11 is connected to the inverter 43 for driving the EL pointer 1. The drive voltage for driving the inverter 43 is input via the transistor 45 acting as a switch, and this drive voltage is also input to the-side input terminal of the comparator 41 via the resistors R ₁ and R ₂ and the capacitor C. It is input as the voltage V _in .

Output side of comparator 41 and power supply voltage V _T
And resistors R ₃ and R ₄ are provided between the output side of the comparator 41 and the base of the transistor 45, respectively.
When the output of is off, it is on, and when it is on, it is off.

In the brightness correction circuit described above, at the moment when the power is turned on, the drive circuit of the EL pointer 1 is off, that is, the transistor 45 is off, and the inverter 4 is turned off.
No drive voltage is supplied to 3. At this time, the resistance value of the photosensor 3 is high. At this time, the drive voltage from the transistor 45 is not input to the comparator 41, and the output of the comparator 41 is at the low level, and the comparator 41 is in the off state. When the comparator 41 is off, a voltage drop occurs due to the resistor R ₃ on the output side of the comparator 41, and in the transistor 45, the voltage on the base side becomes lower than the voltage on the emitter side connected to the power supply voltage V _T. As a result, a potential difference is generated between them, and the emitter and collector are electrically connected to each other to be in the ON state. As a result, the inverter 43 is driven and the EL pointer 1 emits light, and the light emission brightness is detected by the photo sensor 3.

The resistance value of the photosensor 3 is lowered by receiving the light emitted from the EL pointer 1, which causes the magnitude relationship between V _ref and V _in of the comparator 41 to be reversed at a certain point, and the comparator 41 is At that point, the output goes high and turns on. When the comparator 41 is on, the voltage drop due to the resistor R ₃ described above is supplemented by the output voltage value when the comparator 41 is on, and in the transistor 45, conversely to the above, the voltage on the base side is higher than the voltage on the emitter side. Higher transistor 45
Turn off.

When the transistor 45 is turned off, since the drive voltage is not supplied to the inverter 43, the light emission of the EL pointer 1 is stopped, and at the same time, the resistance value of the photo sensor 3 is increased and V _ref and V _{in of the} comparator 41 are again set. The state in which the values of and are reversed is repeated. The drive voltage V _in input to the comparator 41 can maintain the brightness of the EL pointer 1 at a target constant value shown by the broken line in FIG. 8 by adjusting the values of the resistors R ₁ and R ₂ . . It should be noted that the brightness gradually decreases when the driving time reaches T ₁ , which is the case where the deterioration of the EL pointer 1 is accelerated and the brightness correction circuit reaches the correction limit.

As described above, the photo sensor 3 is fixed to the inner surface of the pointer cap 15 at a position facing the light emitting portion 1a of the EL pointer 1, so that the EL pointer 1 rotates as the movement shaft 7 rotates. However, the emission brightness of the EL pointer 1 is accurately detected. Also, the photo sensor 3
By providing the inside of the pointer cap 15, no extra space is required, and the appearance is the same as the conventional one in which no sensor is provided, and it can be said that the photosensor 3 has no adverse effect.

FIG. 4 shows a second embodiment of the present invention. In this embodiment, the return spring 33 is used as a ground electrode common to the EL pointer 1 and the photo sensor 3. That is, the lead wire 27 connected to the negative electrode of the photosensor 3 and the enamel wire 35 wound around the electrode core material 5 serving as the negative electrode of the EL pointer 1 are connected to the return spring 33. The lead wire 29 connected to the + side electrode of the photo sensor 3 is connected to the outer shaft 11 of the movement shaft 7 by soldering. A conductive layer 47 is formed on the transparent electrode layer around the fixed portion of the EL pointer 1 to the movement 7, and the conductive layer 47 is fitted into the notch 13 of the inner shaft 9 and fixed with an adhesive, whereby the conductive layer 47 is formed.
Will be conducted to the inner shaft 9.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, the outer shaft 11 of the movement shaft 7 is
This is used as a ground electrode common to the L pointer 1 and the photo sensor 3. That is, the lead wire 27 connected to the negative electrode of the photosensor 3 and the enamel wire 35 wound around the electrode core material 5 serving as the negative electrode of the EL pointer 1 are connected to the outer shaft 1.
It is connected to 1 by soldering. + Of photo sensor 3
The lead wire 29 connected to the side electrode is connected to the return spring 33 by soldering. The other structure is similar to that of the second embodiment shown in FIG.

In the examples of FIGS. 4 and 5, the photosensor 3 is fixed to the inner surface of the pointer cap 15 with an adhesive so that the EL pointer 1 and the inner shaft 9 are also made of the adhesive.
And can be fixed at the same time, improving workability. Also, FIG.
Also in the first embodiment, the photosensor 3 may be fixed to the inner surface of the pointer cap 15 with an adhesive. In this case, the electrode core material 5 of the EL pointer 1 and the inner shaft 9 of the movement shaft 7 are fixed. If the fixing and the fixing of the lead wire 27 to the inner shaft 9 are also performed with an adhesive, the workability is further improved.

In each of the above-mentioned embodiments, the auxiliary return springs 37 and 39 have the same winding direction as the return spring 33 and have a role of assisting the return force of the return spring 33.
By setting the respective urging forces of 7 and 39 to be equal and the winding directions to be opposite to each other, the two auxiliary return springs 37 and
The rotational force applied to the movement shaft 7 is offset by 39, and it is not necessary to consider the biasing force of the auxiliary return springs 37, 39.

[0039]

As described above, according to the present invention, the brightness detecting sensor for detecting the brightness of the light emitting pointer and holding the brightness constant by the brightness correction circuit is rotated simultaneously with the light emitting pointer. Since the structure is attached to the position of the pointer cap that faces the light emitting part of the light emitting pointer, the light emitting brightness is accurately detected and the brightness is kept constant even if the light emitting pointer is used on a rotating body such as the pointer. be able to.

Further, by using the inner and outer shafts of the movement shaft having a double structure and the return springs as the electrode lead-out portions, the connection between the light emitting pointer and the respective electrode terminals of the brightness detecting sensor can be simplified and at the same time grounded. Since the electrode can be shared by the light emitting pointer and the brightness detecting sensor as an inner shaft, an outer shaft, or a return spring, the number of electrode extraction portions can be reduced and the structure can be simplified.

By fixing the brightness detecting sensor to the inner surface of the pointer cap using an adhesive,
The inner shaft and the electrode core material of the light emitting pointer and one electrode terminal of the brightness detection sensor can be fixed at the same time, and the inner electrode and the transparent electrode layer of the light emitting pointer or a conductive layer electrically connected to the transparent electrode layer by the adhesive. Part and part can be fixed at the same time, improving workability.

By using the auxiliary return spring attached to each of the inner shaft and the outer shaft as the electrode extracting portion, it is possible to easily draw the lead wire from the rotating movement shaft to the brightness correction circuit. Also, by making the biasing forces of the two auxiliary return springs equal and reversing the winding direction, the rotational force applied to the movement shaft by the auxiliary return springs can be offset, and the biasing force of the auxiliary return springs is especially taken into consideration. There is no need.

[Brief description of drawings]

FIG. 1 is a schematic exploded perspective view showing a connection state of respective electrodes of an EL pointer and a photo sensor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a mounting structure of a pointer cap in FIG.

FIG. 3 is a luminance correction circuit diagram to which an EL pointer and a photo sensor in FIG. 1 are connected.

FIG. 4 is a schematic exploded perspective view showing a connection state of respective electrodes of an EL pointer and a photo sensor according to a second embodiment of the present invention.

FIG. 5 is a schematic exploded perspective view showing a connection state of respective electrodes of an EL pointer and a photo sensor according to a third embodiment of the present invention.

FIG. 6 is a voltage-luminance characteristic diagram of an EL pointer.

FIG. 7 is a frequency-luminance characteristic diagram of an EL pointer.

FIG. 8 is a drive time-luminance characteristic diagram of an EL pointer.

[Explanation of symbols]

 1 EL pointer (light emitting pointer) 3 Photo sensor (luminance detection sensor) 5 Electrode core material 7 Movement shaft 9 Inner shaft 11 Outer shaft 15 Pointer cap 31 Insulating tape (insulating layer) 33 Return spring 37, 39 Auxiliary return spring

Claims (8)

[Claims] 1. A light emitting pointer which emits light when a voltage is applied, a rotatable movement shaft having a base end side of the light emitting pointer fixed to a tip, and a fixed portion of the movement shaft and the light emitting pointer. As described above, a pointer cap fixed to the tip of the movement shaft, and a brightness detection sensor attached to a position facing the light emitting portion of the light emitting pointer in the pointer cap and detecting the brightness of the light emitting pointer, and the brightness detection And a brightness correction circuit that adjusts the brightness of the light emitting pointer according to the detection value of the sensor. 2. The light emitting pointer is provided with an electrode core material in the central part and a transparent electrode layer in the outer peripheral part, and the movement shaft has an insulating layer interposed between an inner shaft and an outer shaft, and The shaft is made of a conductive material having a double structure protruding from the tip of the outer shaft, and the inner core is used as a ground electrode at the protruding end portion of the inner shaft from the outer shaft, and the electrode core material of the light emitting pointer is provided. At the same time as being electrically connected and fixed, one electrode terminal of the brightness detecting sensor is connected, and either one of the transparent electrode layer of the light emitting pointer and the other electrode terminal of the brightness detecting sensor is connected to the outer shaft. The other end is attached to the outer peripheral side of the outer shaft via an insulating layer, and is connected to a return spring made of a conductive material for returning the movement shaft, respectively. Brightness correction device. 3. The brightness detecting sensor is fixed to the inner surface of the pointer cap with an adhesive, and the adhesive causes the inner shaft of the movement shaft, the electrode core of the light emitting pointer and one electrode terminal of the brightness detecting sensor to be fixed. 3. The brightness correction device for the light emitting pointer according to claim 2, wherein and are fixed. 4. The light emitting pointer is provided with an electrode core material in the central portion and a transparent electrode layer in the outer peripheral portion, the movement shaft has an insulating layer interposed between an inner shaft and an outer shaft, and The shaft is made of a conductive material having a double structure protruding from the tip of the outer shaft, and is attached to the outer peripheral side of the outer shaft via an insulating layer and is made of a conductive material for returning the movement shaft. Using the spring as a ground electrode, the lead wire connected to the electrode core material of the light emitting pointer is connected to the return spring, and at the same time, one electrode terminal of the brightness detecting sensor is connected to project the inner shaft from the outer shaft. The transparent electrode layer of the light emitting pointer or a conductive layer portion conducting to the transparent electrode layer is electrically connected and fixed to an end portion, and the other electrode terminal of the brightness detection sensor is connected to the outer shaft. Claim 1 Luminance correction device for the described light emitting pointer. 5. The light emitting pointer is provided with an electrode core material in the central portion and a transparent electrode layer in the outer peripheral portion, and the movement shaft has an insulating layer interposed between the inner shaft and the outer shaft, and The shaft is made of a conductive material having a double structure protruding from the tip of the outer shaft, and the outer shaft is used as a ground electrode, and the electrode core material of the light emitting pointer is connected to the outer shaft through a lead wire at the same time. , Connecting one electrode terminal of the brightness detection sensor,
The transparent electrode layer of the light emitting pointer or a conductive layer portion electrically connected to the transparent electrode layer is electrically connected to and fixed to the end of the inner shaft protruding from the outer shaft, and the other electrode terminal of the brightness detection sensor is fixed. The brightness correction device for a light emitting pointer according to claim 1, wherein the brightness correction device is connected to a return spring made of a conductive material for returning the movement shaft. 6. A brightness detecting sensor is fixed to an inner surface of a pointer cap with an adhesive, and the adhesive is used to electrically connect the inner shaft of the movement shaft to the transparent electrode layer of the light emitting pointer or the transparent electrode layer. 6. The brightness correction device for the light emitting pointer according to claim 4, wherein and are fixed. 7. An auxiliary return spring made of a conductive material for assisting the return force of the return spring is attached to the outer peripheral surfaces of the ends of the inner shaft and the outer shaft opposite to the light emitting pointers,
3. The return spring and the auxiliary return spring are connected to a brightness correction circuit.
4. The brightness correction device for the light emitting pointer according to 4 or 5. 8. The brightness correction device for a light emitting pointer according to claim 7, wherein the auxiliary return springs attached to the inner shaft and the outer shaft respectively have opposite winding directions and have the same biasing force.