JP2003114629A - Led illumination device for emission of light with variable color from formed part in transparent body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the visibility and decorating property of a transparent light emitting display body by allowing a formed part in a transparent body to emit light in variable colors with high luminance and to provide a transparent light emitting display board which emits light in variable colors with high luminance for the industrial field. SOLUTION: The characteristics of the light from an LED to brighten the formed body in a transparent body are defined so as to obtain a monochromatic bright formed part having no irregularity in the luminance. Then LEDs of three primary colors of red, green and blue are used to carry out additive color mixing of the three primary colors in the formed part on the basis of the above technique to emit light of variable colors and high luminance. A new printed wiring board to mount the LEDs necessary for the above method is developed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for display means in all industrial fields that require a visible drawing part and also for crafts, ornaments, etc., and contributes to long life and energy saving. An illumination device using LEDs, which is relatively inexpensive and compact, and which performs high-brightness variable color light emission for improving the visibility of a transparent light-emitting display body having a drawing body inside the transparent body. It is about.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 2000-62247 (hereinafter referred to as "intermediate engraving") already exists as a technique for drawing on a transparent body.

Intermediate carving is in the thickness direction of the plate-shaped acrylic,
This is a processing method of making linear scratches in the optical axis direction by a laser beam on the inside of the transparent body by about 1 mm from the front and back surfaces, respectively.

When the laser beam relatively moves on the surface of acrylic resin, an arbitrary shape is formed in one transparent body as shown by two drawing bodies in FIG. 1 (rectangular lines when viewed from the front). Since continuous linear scratches remain on this, this is the drawing body. Therefore, it is a completely transparent body except the drawing body.
The drawing parts 3 and 4 are the cross-sectional parts of the drawing object. Although 3 is a horizontal cross-sectional part, and 4 is a vertical cross-sectional part, only lines appear in the cross-sections.

The scratch on the drawing body causes irregular reflection when light is applied and emits light, but even if a high-intensity LED is used as a light source, it does not emit high-intensity light, and the drawing object is difficult to recognize and lacks in design. , Was not practical.

[0006]

SUMMARY OF THE INVENTION The present invention has a low cost,
It is an object of the present invention to provide an LED lighting device which is necessary to provide a transparent light-emitting body having an intermediate engraving and capable of emitting high-intensity variable color light under the condition of saving space.

[0007]

According to the present invention, there are three types of L, red, green and blue, and monochromatic bright emission in an intermediate engraving drawing body.
By using the ED, the conditions for high-luminance variable color light emission by additive color mixture of the three primary colors are clarified, and a single-color and mixed-color high-luminance light emission of the drawing object is enabled.

Further, a printed wiring board (hereinafter referred to as a board) having an LED mounting portion for realizing these is developed.

[0009]

DETAILED DESCRIPTION OF THE INVENTION

In the intermediate engraving, the central portion of the transparent body (material is acrylic) is formed by a laser processing machine (the processing method is described in Japanese Patent Laid-Open No. 2000-62247, and therefore omitted). The general process is heating, melting, and resolidification.

The irregular reflection layer of light is formed by the unevenness and voids of the solidified portion which are generated at the time of resolidification. An arbitrary aggregate of the irregular reflection layers serves as a drawing body.

The amount of light consumed per diffuse reflection layer is about 1
%.

When the drawing section is viewed from the front of the drawing section, the irregular reflection surfaces in the thickness direction (perpendicular to the LED light) appear as overlapping lines. This is why the drawing body is expressed as a line drawing. From this, the luminous intensity of the drawing unit is increased by the thickness of the drawing body (the amount of diffused reflection light overlapped). Therefore, the drawing body emits light.

However, if it is only this, it does not emit high brightness light. It is necessary to illuminate the drawing unit with a high density of light, that is, with high illuminance, so that the person who sees the light emitting state feels that the light emission is high brightness.

For that purpose, the characteristics of LED light are utilized,
An LED lighting device is required. The structure is such that the LED is attached to the substrate (hereinafter referred to as an LED unit), and the L
The ED unit is located on the side surface of the transparent body (any of the upper, lower, left, and right sides, or the upper, lower, left, right, arbitrary three, or all four side surfaces). However, it is not attached to the back surface because it loses the designability of being transparent.

Further, if a mirror surface body integrated with a cover that enables total reflection is arranged on the side surface where the LED unit is not mounted, it is natural that the utilization efficiency of the LED light is improved.

FIG. 2 shows an example in which the device is attached to the lower part as an embodiment, and is housed in a fixing device for the transparent body, but the invention is not limited to this. You can put it in. In either case, LE is attached to the side surface of the transparent body.
When the D unit is installed, a member for accommodating the LED unit is provided with a housing for the LED light emitting device. Therefore,
The illumination system of LED light is a refraction type.

Therefore, the width of the substrate used for the LED unit must be narrowed.

The characteristics of one LED light will be described below.

When light enters from the side of the transparent body, LE
The D light enters almost perpendicularly to the side surface (incident angle 0 degree), but about 7% of the light amount is reflected by the nature of acrylic.
This reflection (loss of light amount) is constant up to an incident angle of about 20 degrees, and as the incident angle increases, the amount of reflection increases,
It becomes total reflection in degrees.

Therefore, the light distribution half-value angle (details described later) of the LED is limited to about 20 degrees or less.

After entering the light, it reaches the cat body while spreading in a conical shape. At this time, the conical LED light emission angle is
Although it depends on the directional characteristic of the LED light, the directional characteristic is generally limited to a numerical value. Therefore, the directional characteristic is generally an angle formed by the light distribution half-value angle line and the optical axis line (hereinafter referred to as a half-value angle). ). In the LED standard table, the half-value angle of light distribution is
It is defined to indicate an angle of 50% with respect to the luminous flux on the optical axis.

The directional characteristics of the LED light used in the present invention are
The elliptical shape of FIG. 3 is preferable. In the directional pattern as shown in FIG. 4,
Even if the LED is selected by the half-value angle, the characteristics of the LED cannot be utilized.

In the embodiment, the transparent body has a thickness of 11 mm. The emission shape of the conical LED light is LE as shown in FIG.
The radial circle spreads away from D (the difference between the 13 small-angle radial circle and the 14 large-angle radial circle in FIG. 5 is 5 degrees, but the spread differs greatly). Usually, the illuminance of LED light is inversely proportional to the square of the distance. However, when it comes into contact with the surface of the transparent body, it is totally reflected and returns to the transparent body. This total reflection is repeated. Therefore, after the total reflection occurs, the radiation circle does not spread in the thickness direction, so the illuminance is inversely proportional to the distance. This means that the amount of light reaching the drawing body decreases as the distance from the LED increases. Therefore, the smaller the half-value angle, the greater the amount of light that reaches a farther drawing object.

FIG. 6 shows the shape change of the radial circle at that time.
This figure shows that adjacent light does not overlap and a bright and dark portion occurs on the LED side from the minimum radiation circle point. Adjacent light overlaps if it is far from the minimum radiation circle point. When the half-value angle is large, the minimum radial circle points are close to each other.

The matters described in paragraphs 0024 and 0025 conflict with each other in setting the half-value angle of the LED. From these, the half-value angle setting is greatly influenced by the thickness of the transparent body. Considering the thickness of the transparent body used in this example, an ideal angle is about 5 degrees to 7 degrees. In this example, an LED with a half-value angle of 5 degrees was used.

It is possible to increase or decrease the diffused reflection amount of the LED light on the drawing object to some extent by the laser processing method, or the drawing object is expressed by a plurality of lines such as a double line and a triple line. By constructing one diffuse reflection layer, a drawing body with higher brightness can be obtained.

However, it is not preferable to easily increase the amount of irregular reflection per drawing line. In the irregular reflection on the drawing line, comparing the amount of light to be visually observed with the amount of wasted light often results in wasted due to the characteristic of irregular reflection. For this reason, if the amount of diffused reflection is increased, a larger amount of light will be wasted when passing through one layer. Furthermore, depending on the shape of the drawing body, a number of irregular reflection layers may overlap. In this case, the amount of light sharply decreases each time it passes through the irregular reflection layer, causing a sharp decrease in brightness.
As a result, a bright portion and a dark portion occur on the drawing body.

From the above, a drawing body comprising a diffused reflection layer that consumes more light than is necessary is not preferable. But,
The amount of light to be visually observed is proportional to the amount of diffused reflection light of the diffuse reflection layer. In order to efficiently increase the diffused light reflected by the eyes, the illuminance of the LED light that is the incident light may be increased.

However, if the brightness of the drawing body is increased more than necessary, it is too bright and the lines are blurred, resulting in poor design. In the present invention, this measure is taken by controlling the LED luminous intensity described in the three-primary color additive composition.

From the above, the specifications of the LED can be limited as follows. Half-value angle is 5 to 20 degrees. The brightness is 1 to 5 candela. LEDs corresponding to this are all listed in the standard table for red, green, and blue.
There is no need to develop new. Therefore, the cost can be reduced.

In paragraph 0032, the brightness of the LED is shown in luminous intensity rather than luminance. Never express it in brightness.

This is because the brightness is a value obtained by dividing the luminous intensity by the unit area. No matter how high the brightness is, the luminous intensity is small if the area of the light emitting portion is small. An LED with a low luminous intensity does not emit light with high brightness because the illuminance on the drawing object is low.

The reason why the brightness of the drawing object is expressed is that the visual recognition of the drawing object is performed by comparing the brightness with the transparent portion. Further, since the area of the drawing body is determined by each drawing body, the area of each drawing body does not change. Therefore, there is no problem in expressing brightness.

In paragraph 0032, the numerical value of the half-value angle of the LED is wide, from 5 degrees to 20 degrees. This is L
The characteristics have been described on the basis of one ED, and it is the case of monochromatic light. When a large number of monochromatic lights are arranged in 1 to 3 rows, diffuse reflection light illuminates the diffuse reflection layer. This indicates that the irregular reflection layer has an element that smoothes the light energy. Due to this, the part that received the LED light overlappingly,
The brightness difference from the other part is reduced, but the LED
If the illuminance from is low, this effect cannot be used.

If the reflection at the time of light incident on the transparent body (the amount of useless light that does not enter the transparent body) is relatively small and the luminous intensity of the LED is sufficiently high, there is no problem even if the half-value angle is increased a little. . However, such LEDs are rare.

The above has described the monochromatic light emission of the LED. In the case of monochromatic light emission, it can be said that the LED setting is correct if the bright and dark parts cannot be visually recognized on the drawing body and the brightness is high.

However, when the additive color mixture of the three primary colors of red, green, and blue (hereinafter referred to as the three primary colors) is performed, even if the bright and dark parts of the drawing body which cannot be visually recognized as a single light color, the other parts are darkly colored. If there is a bright part, it becomes a color spot.

Therefore, when additive color mixing (hereinafter referred to as color mixing) using LEDs of the three primary colors is performed, luminance unevenness of the drawing portion in each single light color is not allowed. Some products have described that they change to rainbow colors by utilizing luminance unevenness, but if the entire drawing cannot be made an arbitrary color, additive color mixing is not possible. Being able to perform additive mixed food means that white light emission is also possible as a final color mixture.

Under the above conditions, it is necessary to make it possible to change the brightness of the drawing body of each color (hereinafter, referred to as brightness) in a unit of color without any unevenness (mixing of colors is a factor of color matching such as matching brightness of each color and size). I won't. If this is not possible, any intermediate color cannot be emitted.

The luminosity decreases in the order of red, green and blue. Therefore, when the reference color is considered by comparing the brightness of the three colors, blue is the reference color.

On the other hand, since the luminance unevenness is not allowed, it is necessary to use LEDs of the same model number (which are affected by the change in illuminance depending on the distance from the LEDs unless the directional characteristics of the LED light are equal). In the case of the same model number, since the brightness of the blue LED is lower than that of the other colors, the blue LED is also the reference.

Therefore, one having a small half-value angle is selected, and L
It is necessary to reduce the mounting pitch of the ED as much as possible and perform high-intensity blue light emission in the drawing body.

Further, although the mounting pitches of the LEDs of the respective colors are the same and it is necessary to align them, since the luminous intensities of the LEDs of the respective colors of red, green and blue are different, it is necessary to be able to control the luminous intensity electrically.

These conditions are solved by a substrate satisfying the following conditions.

The LED mounting pitches of the three primary colors are the same and small, and it is possible to cope with the difference in electrical specifications (usually green and blue are the same), and all the LED light can enter into the thickness of the transparent body. , A substrate, and a substrate whose width is within 16 mm in order to save space.

FIG. 7 shows a substrate satisfying the conditions.
15. The width of the board is 24 by providing 24 insulating parts with a width of 2 mm on both sides.
It became 5 mm. The width of the conductive part of 19, 20, 21, 22, 23 (the reference character is an electrode) is the width of the lead (terminal line of the LED)
Except for holes, at least 1 mm, width of insulating band between conductive parts is 0.5
mm provided. The diameter of the lead hole was 1 mm, and the LED mounting pitch was 11 mm. The LED lead pitch is 2.5 mm.

LEDs of the three primary colors are arranged on the substrate at the same pitch for each row. Blue LED is attached to the center, and blue and green L
The ED has its positive side connected to a common conductor portion. Red LED
Considering that the applied voltage is different, a separate positive and negative conductor part is provided. Further, in order to electrically control the three colors individually, one of the colors must be made independent.

The LEDs on both sides are tilted red about 5 degrees and green about 2 degrees toward the blue side. Therefore, although the illuminances of the two colors on the drawing portion are slightly lowered, they are close to the blue illuminance, and there is no problem.

The number of LEDs is the same for each color, and is the number obtained by dividing the length of the drawing body by the LED mounting pitch and adding 1. However, since both ends of the drawing body become darker at that number, both ends of the drawing body are darkened. One or more extra LEDs are arranged in each. Extra LE
The number of D is set to 1 or more because the shape of both ends of the drawing object and LE
This is because the required number changes depending on the position from D. Therefore, it is not necessary to have five or more. Further, the number of each LED color does not necessarily have to match in this part.

The length of one board is determined by the permissible current of the board, and the permissible current with respect to the conductor width of the board is determined by the operating current, the ambient temperature and the manufacturing technique. Generally, the thickness of the conductor portion is 0.035 mm, the width is 1 mm, and the length is 100 mm or less, so that the length of one LED lighting unit is ideally 300 mm or less. Factors that determine the length of one unit are the thickness of the board, the area occupied by the mounted parts, the processing method,
There are also warpage, twisting, tolerance, utilization efficiency with respect to the size of the fixed-size plate, etc., but even considering them, it is around 300 mm.

When a printed circuit board longer than that is required, it is connected by a coated conductive wire. As a connecting method, a connecting component may be interposed between the covered electric wire and the substrate, but a space for that is required. Therefore, it is desirable to directly connect the covered electric wire. However, when the conductor portion of the printed circuit board is inserted between the covered electric wire and the covered electric wire, it is necessary not to exceed the allowable current.

The greatest feature of the substrate in the present invention is that the lines at both ends in the width direction of the substrate have zero potential (expressed as negative in DC electricity), and no compensation resistor for the LED is provided in the substrate. The thing is. The experimental contents of the influence of the compensation resistance are described in paragraph 0061 and the results are described in paragraph 0062.

Since the maximum applied voltage to the LED is 5 V or less, there is no electric shock accident, but setting the lines at both ends to 0 potential is advantageous when considering the insulation between both ends and the holding part of the transparent body. , More space saving is possible.

The reason why the compensation resistor is not provided in the substrate is to prevent light and dark in the drawing portion.

Generally, a person skilled in the art would like to use an LED for LED protection.
One resistor is provided for each unit, or one compensation resistor is provided for each unit number of LEDs 3 to 5. However, use of such a large number of resistors not only increases power consumption, but also tends to cause a luminous intensity error of the LED (details will be described later), which causes color spots.

However, it is a fact that a compensating resistor or its substitute component is required. In the present invention, those L
An integrated ED compensation circuit and brightness adjustment circuit was provided outside the substrate.

Monochromatic LE is used for all conductive parts of the three primary color mixed substrate.
When D is attached, it is natural that the illuminance on the drawing body is tripled, and a space-saving light-brightness transparent light-emitting body can be realized. If it is not a variable color, combination of LEDs (for example, one row for red, two rows for blue to purple) makes it unprecedented.
Can emit high-luminance mixed colors. This is true for all visible light colors.

The LED compensating circuit is composed of LEs arranged in parallel.
If for some reason, some of the D's lose power,
The voltage on the LED rises. This is a system in which a voltage rise is sensed, a signal is sent to the inverter circuit, and voltage application to the LED is stopped, and it is not a special circuit.

The configuration of the light intensity adjusting circuit is a simple amplifying circuit in which a volume and a fixed resistor are connected in series, and the current flowing therethrough is used as the base current of the transistor. The fixed resistance is added to the volume because the resistance value of the volume is 0.
This is to prevent an excessive current from flowing to the LED even if it becomes ohmic. If the current consumption of the LED is small, no transistor is needed. From the experiment of paragraph 0061 described later and the result of 0062, a complicated control circuit is no longer necessary.

The outline of the experiment is as follows: 20 blue LEDs are arranged side by side, a DC power supply voltage of 5 V is applied, and a compensation fixed resistance of 1/8 W, 90 ohm is individually provided.
2W, 200 ohm variable resistor (LE
(In order to confirm the difference due to the fluctuation of the applied voltage with respect to D), a comparison was made in the case where a concentrated compensation resistor (a resistor was installed only in the power supply section) was used.

When a compensation resistor is added to each LED, LE
LED forward voltage is 3.51 for D forward voltage 3.5V
A voltage error between individual LED terminals of 3.41V from V and a maximum of 0.1V was produced. As for this voltage difference, the brightness difference in the drawing body was visually recognized. On the other hand, in the concentrated compensation resistance circuit,
The error between the D terminal voltage of 3.51V to 3.52V (any applied voltage because it is a variable resistor) is 0.01V,
The brightness difference on the drawn body was not visible.

When confirming the presence or absence of an error in the electrical performance of each LED with the manufacturer, it was found that there was an error that could not be visually recognized. As a result of the above, it was determined that the error was visually recognizable due to the synergistic effect of this error and the error of the fixed resistance, and the present invention adopted the concentrated compensation resistance method.

The number of LEDs of each color of the three primary color mixed color LED unit is set to 3 to 5 to form an independent block.
When eight pieces are arranged side by side, any color can be emitted in each independent block, so that the drawing body can be expressed in rainbow colors. A smooth color change can be made between blocks because the color is an intermediate color between the blocks. Of course, since the color of each block can be changed by the signal from the control circuit, the color can be changed in a flowing manner.

In this case, a program sequencer or personal computer is used as the control device. Since the program sequencer and personal computer have extra functions, it is natural that a new circuit can be manufactured without unnecessary functional parts. In this example, a program sequencer was used.

[0066]

【The invention's effect】

By analyzing the LED light characteristics and adopting the concentrated compensation resistance method, all visible light colors can be emitted at high brightness without color spots in the drawing portion, and white light can also be emitted.

By adopting the concentrated compensation resistance system,
Since no resistance is added to the ED, power saving and heat generation in the LED unit can be minimized.

Since the three colors of red, green, and blue are divided for each column in the LED mounting circuit of the substrate, it is possible to combine the two types of LED colors and perform limited variable color high brightness light emission.

By combining a high luminous intensity, low half-value angle LED and a substrate without a resistor, a high-brightness transparent illuminant can be obtained.

[Brief description of drawings]

FIG. 1 is a transparent body, a transparent body drawing portion, and L in the present invention.
The partially broken external view which shows the structure of an ED illumination device.

FIG. 2 is a longitudinal sectional view showing an example of an LED illumination device, a transparent body fixing device, a transparent body, and a drawing body when the LED illumination device has the minimum width in the present invention.

FIG. 3 is a diagram showing a relationship between a directional characteristic diagram of an LED and a light distribution half-value angle.

FIG. 4 is an example of a directional characteristic diagram of an LED unsuitable for an LED according to the present invention.

FIG. 5 is a diagram showing a relationship between a radiation circle of LED light and a radiation angle.

FIG. 6 is a comparison diagram of shapes before and after total reflection in a radiation circle of LED light.

FIG. 7 is a printed wiring diagram of the present invention.

[Explanation of symbols]

1 Transparent part of transparent body 2 Drawing body inside transparent body 5 LED 6 specular reflection cover 7 LED lead 8 Transparent body fixing device 9 substrates 10 Light distribution half-value angle line showing the directivity of LED 19 Green LED cathode conductive part 20 Common anode conductive part of green and blue LEDs 21 Blue LED cathode conductive part 22 Anode conductive part of red LED 23 Cathode conductive part of red LED 24 Lead passing hole for soldering LED lead 25 Insulation band between board and outside 26 wiring space 27 Green LED 28 blue LED 29 Red LED

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Claims (4)

[Claims] 1. A single printed circuit board is provided with three types of LEDs of red, green and blue closely arranged for each color to form an LED.
2. An LED illumination device, characterized in that the luminous intensity of each of the columns is controlled by an electric means for each column, and additive color mixing is performed by a drawing body inside the transparent body so that the drawing body emits light with high brightness variable color. 2. The LED according to claim 1, wherein the luminous intensity is 1 candela or more and 5 candela or less, and half-value angle is 5 degrees or more and 20 degrees or less.
An LED illuminating device using an ED. 3. An LED lighting device, wherein the LED compensation resistor is not provided in the printed circuit board according to claim 1. 4. The substrate according to claim 1 or 3 and the LED according to claim 2 are used, and one type of LED emission color, or
An LED illuminating device characterized in that a drawing portion inside a transparent body is made to emit high-luminance light of an arbitrary color by limiting to two types.