JP2539823B2 - Lighting equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an illumination device using an LED array.

2. Description of the Related Art Conventionally, an illuminating device using this type of LED array has been used for scanners and the like. An example thereof will be described with reference to FIG. First, between the document surface 1 and the array-shaped sensor 2 which is long in the width direction of the document surface 1, a self-locking lens 3 which is also long in the width direction of the document surface 1 and formed in an array is provided. ing. This self-locking lens 3
Thus, the optical information on the line of the point O on the document surface 1 is imaged on the reading portion of the sensor 2. in this case,
In order to obtain the brightness of the document surface 1 for reading, an LED array 4 which is long in the width direction of the document surface 1 is provided. This LED array 4 has a large number of light emitting elements 7 arranged in a straight line on a substrate 6 having a heat dissipation plate 5 fixed to the back surface, and a support member 8 is provided on the normal line of the light emitting element 7. A bar lens 9 held at a fixed position is provided.
The light flux from the bar lens 9 is set to form an image at the point O on the document surface 1.

Since the substrate 6 of the LED array 4 has to be patterned on its surface with wiring portions for a large number of light emitting elements 7, its width cannot be set to a predetermined width or less. That is, the width dimension needs to be about 10 mm. Therefore, the distance between the light emitting element 7 and the point O on the document surface 1,
That is, the optical path length L ₁ becomes large, and the light emitting element 7 cannot be brought close to the point O. This optical path length L ₁ is the distance l ₁ from the light emitting element 7 to the surface of the bar lens 9 and the bar lens 9
₁ and the distance l ₃ between the bar lens 9 and the point O are added. To give an example of these dimensions, l ₁ is 1.
5 mm, l ₂ is 4.0 mm, l ₃ is 5.0 mm, optical path length L ₁ is 10.5 mm
Is.

Such an optical path length L ₁ is preferably as short as possible from the viewpoint of increasing the amount of light at the point O on the document surface 1. However, since the width dimension of the substrate 6 cannot be reduced as described above, the optical path length L ₁ is considerably long. Therefore, in order to obtain a sufficient amount of light on the document surface 1, it is necessary to increase the amount of light emitted from the light emitting element 7. However, in this case, the amount of heat generated is inevitably increased, which causes another thermal problem. To do.

Next, although the one shown in FIG. 11 is another example of the related art, the same LED array 4 as that shown in FIG. 10 is used. In this case, a roof mirror lens array (RMLA) 10 is provided between the document surface 1 and the sensor 2. This roof mirror lens array 10
The housing 11 is provided with a roof mirror array (RMA) 12, a lens array (LA) 13, and an optical path separation mirror (SM) 14. Then, the image of the point O on the document surface 1 illuminated by the LED array 4 is reflected by the optical path separation mirror 14 and passes through the lens array 13, the roof mirror lens array 10, the lens array 13, the optical path separation mirror 14 to the sensor 2. Form an image. Therefore, since the height dimension of the roof mirror lens array 10 is small, the LED array 4 has the characteristic that the distance between the document surface 1 and the sensor 2 can be reduced.
Since the structure is similar to that described above, the optical path length between the light emitting element 7 and the point O on the document surface 1 cannot be shortened. Therefore, this type also has the same drawbacks as those shown in FIG.

Purpose The present invention has been made in view of the above points, and LED
An object of the present invention is to obtain an illuminating device capable of significantly increasing the effective illumination light in the original illumination by the array.

Configuration The present invention is an LED array in which a large number of light emitting elements are arranged on a substrate in a straight line, and a reflector provided along the arrangement direction of the light emitting elements while being inclined with respect to the surface of the substrate, The bar lens is located between the reflection plate and the substrate and transmits the reflected light from the reflection plate. With this, even if the width dimension of the substrate on which the light emitting element is provided is large, the direction of the surface of the substrate can be made parallel to the direction of the light that illuminates the document surface because the reflecting plate exists. The light emitting element can be brought close to the position where the original surface should be illuminated without being restricted in space, and the optical path length can be shortened. Therefore, if the LED array has the same emission brightness as the conventional one, The effective illumination light can be greatly increased, and high-speed scanning is possible. If the same effective illumination light as the conventional one is sufficient, the power consumption of the LED array can be significantly reduced and the heat generated can be suppressed.
It is configured so that the life can be increased.

The first embodiment of the present invention will be described below with reference to FIGS. 1 to 4. First, the LED array 15 is provided with a substrate 17 having a predetermined width in which a large number of light emitting elements 16 are arranged in a straight line, and a heat radiating plate 18 is fixed to the back surface of the substrate 17.
On the surface of such a substrate 17, a bright aluminum plate is punched and bent to be electrically insulated from a pattern or the like (not shown), and a reflection plate 19 is fixed. This reflector 19
Is a first reflecting surface inclined at 45 degrees with respect to the surface of the substrate 17.
20 and a second reflecting surface 21 parallel to the surface of the substrate 17. Then, these reflecting surfaces 20 and 21 and the substrate 1
Bar lens 22 with a circular cross section that contacts and fixes the surface 7
Is provided.

Further, a direction A-A 'which is orthogonal to the direction of the surface of the substrate 17
A document surface 23 is provided with a plane inclined by an angle θ with respect to.

The one shown in FIG. 4 corresponds to the above-mentioned FIG. 10 and is used in a reading device in which a self-locking lens 25 is interposed between a document surface 23 and a sensor 24 facing it. is there.

In such a configuration, the luminous flux Φ from the light emitting element 16
₁ is reflected by the anti-slope 20 and then transmitted through the bar lens 22 to be focused on the illuminated point O. The luminous flux Φ ₂ directly passes through the bar lens 22, is reflected by the reflecting surface 21, and is condensed on the illuminated point O.

Therefore, when the reading device is configured as shown in FIG. 4, even if the width of the substrate 17 is large, the direction thereof is parallel to the optical path. Therefore, as described above, the luminous flux Φ ₁ and the luminous flux Φ ₂ Among them, the optical path length L ₂ of the luminous flux Φ ₁ can be shortened.
As an example, the distance l ₄ between the light emitting element 16 and the reflecting surface 20
Is 1.0 mm, the distance l ₅ between the reflecting surface 20 and the surface of the bar lens 22 is 0.5 mm, the diameter l ₆ of the bar lens 22 is 2.0 mm, and from the surface of the bar lens 22 to the illuminated point O. The distance l ₇ is
It is 2.5 mm. However, the sum of these is the optical path length L
₂ is 6.0 mm.

For this reason, even when viewed only for emission flux [Phi _1, when compared with that shown in FIG. 10, the illuminance E? ₁ of the illuminated point O ratio of the optical path length of both the L ₁ / L ₂ To increase. Based on the above-mentioned concrete numerical value, this ratio of L ₁ / L ₂ is about 1.75 (10.5 ÷ 6.0) times.

From this, the improvement of the illuminance of the specific illumination point O by the luminous flux Φ ₁ is Becomes Here, γ is the reflectance and EΦ ₀ is the illuminance at the illuminated point o in the conventional LED array.

Furthermore, since the luminous flux Φ ₂ exists, the effective illumination light is improved. That is, assuming that the divergence characteristic from the light emitting element 16 is close to the perfect diffusion characteristic, the luminous divergence is determined by the light amount in the angular direction according to the Hoot-Lambert's law. Therefore, the light amount distribution at the illuminated point O is synthesized as shown in FIG.

Here, the reason why the luminous flux Φ ₂ has a spread distribution is that the light condensing system of the luminous flux Φ ₂ is a magnifying system having a higher magnification than the condensing system of the luminous flux Φ ₁ . Therefore, if these magnification relationships are properly set, the combined illuminance distribution EΦ _T shown in FIG. 4 can be made into an appropriate profile such as a peak value and a half value width.

Then, if the magnification of the magnifying system of the luminous flux Φ ₂ is m, the improvement in illuminance is Therefore, as a whole, an increase in light amount of η = η ₁ + η ₂ can be obtained. Measured about 1.5 to 1.7
The illuminance was doubled, and a value that almost matched the approximate calculation was obtained.

Then, the one shown in FIG. 5 has been described in the above embodiment.
The roof mirror lens array 10 described in FIG. 11 is a combination of the LED array 15, the reflector 19 and the bar lens 22.
It was used for. Also in this case, since the direction of the substrate 17 is parallel to the light flux, there is no restriction in space, and high illumination efficiency is obtained as in the above-mentioned embodiment.

Next, a second embodiment of the present invention will be described based on FIG. In this embodiment, the reflection plate 24 is different from the reflection plate 19 of the above-mentioned embodiment, and is formed by plastics, and the first reflection surface 25 and the second reflection surface 26 are formed by the reflection film. It is a thing.

When the reflector 24 is molded by plastic in this way, as shown in FIG. 7, a partition 27 having a reflective film formed on the surface is formed in accordance with the pitch of the light emitting element 16, and the partition 27 is formed.
If the bar lens 22 is brought into contact with 27 and installed, the bar lens
The light inclined in the longitudinal direction of 22 as shown by the broken line is reflected by the partition wall 27 and enters the bar lens 22 at a large angle. As a result, in the state where the partition wall 27 is absent as shown by a broken line, the light that cannot be effectively used due to the surface reflection on the surface of the bar lens 22 is reflected by the partition wall 27 as shown by a solid line to be effectively used. Therefore, the lighting efficiency can be improved.

A third embodiment of the present invention will be described with reference to FIG.
This embodiment is different from the first embodiment in that the shape of the reflection plate 28 is only the first reflection surface 29. Therefore, of the luminous flux Φ ₁ and the luminous flux Φ ₂ shown in FIG.
29 uses only the luminous flux Φ ₁ . In this case as well, a sufficient increase in the amount of light is obtained as shown in the equation.

The LED array 15 having such a structure is used in the roof mirror lens array 10 shown in FIG. 11 as shown in FIG. In this case also, the direction of the substrate 17 is parallel to the light flux, so there is no space restriction,
Similar to the first embodiment, high illumination efficiency is obtained.

Effect As described above, the present invention provides an LED array in which a large number of light emitting elements are linearly arranged on a substrate, and a reflection provided along the arrangement direction of the light emitting elements while being inclined with respect to the surface of the substrate. Since the plate and the bar lens that is located between the reflector and the substrate and transmits the reflected light from the reflector are used, the light is reflected even if the width of the substrate on which the light emitting element is provided is large. Since there is a plate, the direction of the surface of the substrate can be made parallel to the direction of the light that illuminates the document surface, which allows the light emitting element to be positioned at the position where the document surface should be illuminated without being restricted by space. Since they can be brought close to each other and the optical path length can be shortened, therefore, if the LED array has the same emission brightness as the conventional one, the effective illumination light can be greatly increased and high-speed scanning can be performed. The same as the conventional If the effective illumination light is sufficient, the power consumption of the LED array can be significantly reduced, its heat generation can be suppressed, and the life can be increased.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment of the present invention, FIG. 2 is an enlarged side view showing the state of the luminous flux, and FIG. 3 is a graph showing the light quantity distribution at an illuminated point, FIG. Is a side view of a reading device using a self-locking lens, FIG. 5 is a side view of a reading device using a roof mirror lens array, and FIG. 6 is a second embodiment of the present invention. A side view, FIG. 7 is a vertical sectional front view showing a modification thereof, FIG. 8 is a side view showing a third embodiment of the present invention, and FIG. 9 is a state in which it is used in a reading apparatus using a roof mirror lens array. FIG. 10 is a side view showing a conventional example, and FIG. 11 is a side view showing another conventional example. 15 ... LED array, 16 ... Light emitting element, 17 ... Substrate, 19 ...
… Reflector, 22 …… Bar lens, 24 …… Reflector, 28 …… Reflector

Claims (1)

(57) [Claims] 1. An LED array in which a large number of light emitting elements are arranged on a substrate in a straight line, a reflector which is inclined with respect to the surface of the substrate and is provided along the arrangement direction of the light emitting elements, An illuminating device comprising a bar lens, which is located between a reflector and the substrate and transmits reflected light from the reflector.