TW201903318A - Light source device - Google Patents

Abstract

The present invention implements a light source device that achieves suppression of luminance degradation and suppression of uneven illuminance using a simple optical system configuration. A light source device is provided with: a light source unit that includes a plurality of LED elements; a first optical system that narrows the divergence angle of light emitted from the light source unit without collimating the light; a second optical system that condenses light emitted from the first optical system; and an integrator optical system that has an incidence surface disposed at a focus position of the second optical system.

Description

Light source device

The present invention relates to a light source device, and more particularly to a light source device having a plurality of LED elements.

Previously, light processing techniques that utilized light were utilized in a wide variety of fields, such as the use of exposure devices using microfabrication of light. In recent years, exposure technology has been developed in various fields, and even in fine processing, it has been used for the production of relatively large patterns and three-dimensional fine processing. More specifically, for example, the production of an electrode pattern of an LED, a manufacturing process of a MEMS (Micro Electro Mechanical Systems) represented by an acceleration sensor, and the like are performed using an exposure technique.

Among these light processing technologies, as a light source, a high-intensity discharge lamp has been used from the past. However, with the advancement of solid-state light source technology in recent years, it has been reviewed as a light source to use a plurality of LEDs.

Patent Document 1 described later discloses an optical system that condenses light that is emitted from a plurality of LED elements into parallel light and that is incident on a cylindrical optical integrator. Patent Document 2, which will be described later, discloses that the light emitted from the enlarged real image is transmitted to the illuminated surface through the collecting lens after the light emitted from the plurality of LED elements passes through the lens array to generate an enlarged real image as the secondary light source. system. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP-A-2014-207300 (Patent Document 2) JP-A-2006-133635

[Problems to be solved by the invention]

The LED element is an element that emits light by circulating an electric current to the semiconductor layer. Then, in the light-emitting surface of the LED element, a region having a high luminance and a region having a low luminance are likely to be present, and luminance unevenness at a place where it is likely to occur is likely to occur. For example, when an electrode for supplying a current to a semiconductor layer is disposed on the light-emitting surface side of the LED element, a place where the electrode is formed becomes a non-light-emitting region, so that brightness is inevitably generated where the electrode is formed and where the electrode is not formed. uneven distribution. Further, even in the case where an electrode for supplying a current to the semiconductor layer is disposed on the surface opposite to the light-emitting surface of the LED element, a difference in current density occurs in a region in the vicinity of the electrode and in a region apart from the region. There is a situation in which the distribution of the brightness is generated. Further, in the case where the electrode for supplying a current to the semiconductor layer is disposed on the surface opposite to the light-emitting surface of the LED element, it is also considered that the electrode on the back side is directly reflected on the light-emitting surface side, and is formed on the light-emitting surface. The condition of an area with low brightness.

In the technique of Patent Document 1, after the emitted light from each of the LED elements is made parallel, the cylindrical optical integrator is placed at the focus position of the condensing lens by condensing the condensing lens. Therefore, in the light incident surface of the cylindrical optical integrator, the emitted light from each of the LED elements is concentrated at a point, so that high luminance can be achieved.

However, on the light incident surface of the cylindrical optical integrator, the light-emitting surface of each LED element appears as an image. Therefore, there is a luminance unevenness as described above on the incident surface. In the cylindrical optical integrator, since the incident light is repeatedly reflected and mixed, it is expected that the illuminance unevenness is suppressed in comparison with the light incident surface on the light exit surface of the cylindrical optical integrator. However, in order to fully realize this effect, it is necessary to sufficiently ensure the number of reflections, and it is necessary to arrange a relatively large cylindrical optical integrator.

According to the technique of Patent Document 2, an enlarged real image of each LED element is disposed by a lens array provided on the front surface of the condensing lens, whereby a secondary light source is substantially generated. Since the secondary light source is disposed in a state where the interval between the adjacent LED elements is narrower, the luminance unevenness due to the presence of the non-light-emitting region in which the adjacent LED elements are spaced apart is alleviated. Then, the light emitted from the condensing lens is formed so as to be concentrated at a position different depending on the divergence angle, so that a smooth illuminance distribution on the irradiation surface can be realized. Thereby, illuminance unevenness due to unevenness in luminance existing on the light-emitting lines of the respective LED elements is alleviated.

However, since the light is concentrated on the optical system at different positions on the irradiation surface, it is inevitable that the average brightness in the effective irradiation area is lower than the highest brightness in the irradiation area. In the method of Patent Document 2, it is considered that the lens array in which a plurality of segments are arranged is used to take measures against the decrease in brightness. However, the optical system is complicated, and the scale of the device is enlarged and the problem of complicated optical axis adjustment is caused.

The present invention has been made in view of the above-described problems, and an object of the invention is to provide a light source device that suppresses a decrease in luminance and suppresses illuminance unevenness by a simple optical system structure. [Means to solve the problem]

A light source device according to the present invention includes: a light source unit including a plurality of LED elements; and a first optical system that prevents light rays emitted from the light source unit from being parallel and narrows a divergence angle; and the second optical system is a pair of slaves The light emitted from the first optical system is condensed, and the optical system of the concentrator is disposed at a focal position of the second optical system.

According to the foregoing configuration, the plurality of light beams emitted from the plurality of LED elements are incident in the second optical system and are non-parallel. Therefore, in the focus position of the second optical system, the plurality of light rays are not concentrated at one point, but are concentrated in a region having a predetermined size. Since the incident surface of the optical unit optical system is disposed at the focal position, the image of the LED element itself does not clearly appear on the incident surface of the optical system of the optical device, but the so-called "out of focus" The state of ") appears like an image.

The aforementioned configuration is such that it intentionally directs light into the incident surface of the optical unit of the optical device in a blurred state. At this time, the luminance unevenness that occurs in the light-emitting surface of the LED element accompanying the light-emitting region and the non-light-emitting region formed by the electrode or the like is also present on the incident surface of the optical unit of the optical device in a blurred state. Thereby, a part of the region having a low luminance corresponding to a place where the light emitted from the LED element where the electrode is present (non-light-emitting region) is guided corresponds to a place where the light emitted from the light-emitting region is guided. A part of the region having a high luminance overlaps the entrance surface of the optical unit of the concentrator. As a result, compared with the structure of the patent document 1, the unevenness of the brightness on the incident surface of the optical system of the illuminator is lowered, and the illuminance unevenness on the irradiation surface of the light emitted from the optical system of the illuminator is also lowered. Here, the "irradiation surface" means a region where light rays to be emitted from the light source device of the present invention are intended to be used.

Further, according to the above configuration, it is possible to realize only the light emitted from the plurality of LED elements in a blurred state to be guided to the incident surface of the optical unit of the optical device. Therefore, compared with the structure of Patent Document 2, It is realized with an extremely simple optical system. Further, since the incident surface of the optical unit optical system is at the focus position of the second optical system, the light incident on the incident surface of the optical unit of the optical splicer can ensure high luminance. Then, the high-intensity light is emitted through the optical system of the illuminator to the irradiation surface. That is, compared with the configuration of Patent Document 2, high-intensity light can be guided to the illuminated surface.

Further, according to the above configuration, for example, by adjusting the distance between the first optical system and the second optical system, the focus of the image guided to the incident surface of the optical unit of the optical device can be easily adjusted. When the direction in which the focus of the image is aligned is adjusted, the brightness on the incident surface of the optical unit of the illuminator can be increased, and the unevenness of the brightness on the incident surface is likely to appear. Conversely, if the direction in which the focus of the image is deviated is adjusted, the unevenness in brightness on the incident surface of the optical system of the concentrator can be eliminated, and the brightness on the incident surface is lowered. The response of the random strain can be performed in response to the request of the application using the light emitted from the light source device.

The LED element is a line-shaped electrode provided on a side opposite to the first optical system, and having a light-emitting surface and a light-emitting surface; and a maximum emission of light emitted from a center point of the LED element The angle is θ ₁ , the condensing angle of the light rays emitted from the second optical system is θ ₂ , the width of the electrode is set to d ₁ , and the light ray is emitted from the second optical system and traverses the focus position. when the length of the optical axis L ₁ when it is set to the value of L ₁ satisfies the above formula (1) in such manner as to adjust the position of the first optical system and the second optical system also,

The optical system of the illuminator may be configured by fly spectacles in which a plurality of lenses are arranged in a matrix. [Effects of the Invention]

According to the light source device of the present invention, it is possible to suppress the decrease in luminance and the suppression of illuminance unevenness by a simple optical system.

Hereinafter, the light source device of the present invention will be described with reference to the drawings. Furthermore, the size ratio of each figure does not necessarily coincide with the actual size ratio.

Fig. 1 is a view showing an example of an optical system of a light source device. The light source device 1 includes a light source unit 2, a first optical system 5, a second optical system 7, and an optical unit optical system 8.

The light source unit 2 includes a plurality of LED elements 3. In the present embodiment, as an example, the plurality of LED elements 3 are disposed on a predetermined plane (herein, an X-Y plane). However, in the present invention, the configuration of the plurality of LED elements 3 may be any form. In addition, in FIG. 1, the direction of the optical axis 11 is made into the Z direction.

The first optical system 5 is configured such that the optical beams that are emitted from the plurality of LED elements 3 are not paralleled, and the divergence angle is reduced, and the plurality of lenses 6 are disposed corresponding to the respective LED elements 3. In FIG. 1, the configuration in which one lens 6 is disposed corresponding to each of the LED elements 3 is shown. However, the plurality of lenses 6 may be disposed in the direction of the optical axis 11 for each of the LED elements 3.

The second optical system 7 condenses the light emitted from the first optical system 5 to the optical system of the focal point 7f of the second optical system 7.

In the present embodiment, the optical unit optical system 8 is constituted by the fly glasses 10. The fly glasses 10 are arranged such that the incident surface 10a becomes the position of the focus 7f of the second optical system 7. However, in the present specification, the term "arranged to the focus position" includes a position in which the focus distance is shifted by only ±10% in the direction parallel to the optical axis 11 except for the case where the focus position is completely matched. Further, the optical axis 11 of Fig. 1 is an axis orthogonal to the incident surface of the optical unit 8 such as the incident surface 10a of the fly glasses 10.

The light emitted from each of the LED elements 3 travels through the first optical system 5 and the second optical system 7 toward the incident surface 10a of the fly's eyeglasses 10. Since the second optical system 7 is a collecting optical system, each light beam travels toward the focus 7f of the second optical system 7. However, as described above, the light rays emitted from the first optical system 5 are not collimated. Therefore, the light rays incident on the incident surface 10a of the fly spectacles 10 are not concentrated at one point but are concentrated in the region 13 having the width.

At this time, on the incident surface 10a of the fly spectacles 10, the image of the LED element 3 appears in a blurred state. That is, the image is displayed in a state where the focus is not aligned. Further, in Fig. 1, the position where the image of the LED element 3 is imaged when the fly glasses 10 are not present is indicated by reference numeral 15.

2 is a schematic plan view of the LED element 3 viewed from the light extraction surface side, that is, the first optical system 5 side in the Z-axis direction. The LED element 3 has a light-emitting region 22 for taking out light generated in the semiconductor layer, and a linear electrode 21 for supplying a current to the semiconductor layer. Further, in FIG. 2, a lead wire 14 for supplying a current from the outside to the electrode 21 is connected.

The electrode 21 is made of, for example, Ni/Al/Ni/Ti/Au, Cr/Au, Ti/Pt/Au, Ti/Pt/Cr/Au/Cr/Pt/Au or the like. That is, the electrode 21 is made of a material that completely or hardly transmits light generated by the LED element 3, and constitutes a non-light-emitting region. That is, the light emitting surface of the LED element 3 has the light emitting region 22 and a non-light emitting region formed by the electrode 21.

As described above, according to the configuration of the present embodiment, the image of the LED element 3 in a blurred state appears on the incident surface 10a of the fly's eyeglasses 10. Thereby, a part of the image of the non-light-emitting region formed by the electrode 21 is overlapped with a part of the image of the light-emitting region 22. As a result, light rays whose uneven brightness is moderated are incident on the incident surface 10a.

Further, the incident surface 10a of the fly glasses 10 is disposed at a focus position of the second optical system 7. Therefore, on the incident surface 10a, the light emitted from all the LED elements 3 is concentrated in the narrow region 13, and the fly glasses 10 are incident on the high-intensity light. Thereby, it is possible to provide high-intensity light to an application that uses the light emitted from the fly-eye glasses 10.

3A to 3D are diagrams showing the action of the present invention. 3A to 3C are views showing a view of an image on the light incident surface of the fly glasses 10 when the focus of the LED element 3 is aligned with the fly glasses 10. The focus of the LED element 3 is matched to the condition of the fly spectacles 10, and corresponds to, for example, the state in which the light beams emitted from the LED elements 3 are parallel and then incident on the second optical system 7.

Fig. 3A is a view showing the image of the image on the incident surface of the fly spectacles 10, and Fig. 3B is a view showing only the respective regions of the fly spectacles 10 from Fig. 3A. In FIGS. 3A and 3B, the pattern 21b of the electrode 21 and the image 22b of the light-emitting region 22 are visually displayed on the incident surface of each of the fly glasses 10.

As shown in FIG. 3A and FIG. 3B, when the focus of the LED element 3 is aligned with the fly glasses 10, the image 3b of each LED element 3 is overlapped on the illuminated surface of the light emitted from the fly glasses 10 as shown in FIG. 3C. Display on the ground. As a result, in the irradiated surface, in the region where the image 21b of the electrode 21 overlaps and overlaps with the image 22b of the light-emitting region 22, a difference in luminance is likely to occur. In Fig. 3C, the image of the outer peripheral portion of the fly spectacles 10 is indicated by 10b.

On the other hand, in the present embodiment, when the focus of the LED element 3 is deviated from the fly glasses 10, as shown in FIG. 3D, the image 10b on the outer peripheral portion of the fly glasses 10 is deviated, so that the image 21b of the electrode 21 and the light-emitting area 22 are The 22b overlaps and overlaps, respectively. As a result, the difference in luminance on the illuminated surface is alleviated as compared with the state of FIG. 3C.

Fig. 4 is a view showing a plane of light emitted from an LED element 3. In FIG. 4, θ ₁ is the maximum radiation angle of the light emitted from the center point of the LED element 3, and θ ₂ is the condensing angle after the light emitted from the center point of the LED element 3 is emitted from the second optical system 7. Further, L ₁ is a length orthogonal to the optical axis 11 when the light ray is incident on the second optical system 7 and straddles the focal position 7f of the second optical system 7.

In Figure 2, the electrodes of the LED element 3 is provided with a width D ₁ is set to 21, then after to satisfy the above formula (1) in such manner as to adjust the position of the first optical system and second optical system 5 is preferably 7.

When the size of L ₁ is excessively reduced, the brightness on the incident surface 10a of the fly glasses 10 becomes high, but the light-emitting region 22 on the LED element 3 and the electrode 21 constituting the non-light-emitting region are clearly displayed. As a result, the unevenness in brightness on the incident surface 10a is conspicuous. On the other hand, if the size of L ₁ is excessively increased, the luminance of the light-emitting region 22 and the electrode 21 on the LED element 3 is blurred, and although the brightness on the incident surface 10a of the fly-eye lens 10 is not uniform, the incident surface is The brightness on 10a will decrease.

The size of the non-light emitting region depends on the width of the electrode 21. Therefore, in the LED element 3 having a large width of the electrode 21, uneven brightness on the incident surface 10a easily occurs. In such a situation, the degree of blurring on the incident surface 10a is increased to improve the performance of reducing unevenness in brightness. Conversely, in the LED element 3 having a small width of the electrode 21, the degree of blurring is lowered to enhance the brightness on the incident surface 10a. Thereby, it is possible to provide light for suppressing both the decrease in luminance and the unevenness in illumination for an application using light.

As an example, when θ ₁ =120°, θ ₂ =3°, and d ₁ =15 μm, it is 1.2 mm ≦L ₁ ≦30 mm. As the value obtained, θ ₁ is 60° or more and 150° or less, θ ₂ is 1° or more and 50° or less, and d ₁ is 5 μm or more and 100 μm or less.

[Other Embodiments] Hereinafter, other embodiments will be described.

<1> In the above-described embodiment, it has been described that each of the optical systems is disposed such that the position 15 which is imaged by the image of the LED element 3 becomes a position closer to the rear than the incident surface 10a of the fly glasses 10. However, as shown in FIG. 5, each optical system may be disposed so that the position 15 imaged by the image of the LED element 3 becomes a position closer to the front than the incident surface 10a of the fly glasses 10. Even in this case, in the region 13 on the incident surface 10a of the fly spectacles 10, the image of each LED element 3 appears in a blurred state.

<2> In the above embodiment, the situation in which the fly illuminator 10 is configured with the fly spectacles 10 will be described. However, as shown in FIG. 6, the concentrator optical system 8 may be configured by a cylindrical optical integrator 30.

The cylindrical optical integrator 30 is a light guide that is configured to uniformly illuminate the illuminance distribution of the light of the exit surface 30b while repeatedly reflecting the light incident on the incident surface 30a on the side surface. An example of a member (light guide). Such a light guiding member is configured, for example, by a columnar member made of a light transmissive material such as glass or resin, or a hollow member having a mirror surface on its inner surface. The latter constructor has a condition especially called an optical channel. Further, the light guiding member may be formed in the interior thereof, and may be divided into a plurality of optical paths in a direction parallel to the optical axis.

However, the fly-eye lens 10 is an optical member in which the image of each of the divided lenses is overlapped on the irradiation surface to uniformize the illuminance, whereas the cylindrical optical integrator 30 uses the light emitted from the light-emitting surface. An optical member that repeats reflection inside the cylindrical optical integrator 30 to achieve uniformity of illuminance. Therefore, the fly glasses 10 are easily affected by the difference in luminance on the light-emitting surface of the LED element 3 as compared with the cylindrical optical integrator 30. Therefore, as described in the above embodiment, when the optical organizer optical system 8 is configured by the fly glasses 10, the effect of eliminating luminance unevenness can be further ensured.

<3> The present invention does not exclude the fact that the reflective optical system is appropriately disposed between the light source unit 2 and the first optical system 5, and the traveling direction of the light is changed. Further, the present invention does not exclude that each of the LED elements 3 included in the light source unit 2 is disposed substantially on the XY plane, and a plurality of LED elements 3 are arranged in the Z direction. The reflective optical system is disposed between the light source unit 2 and the first optical system 5 as appropriate, and the same is true in the case where the plane of each of the LED elements 3 is substantially different from the plane of the XY plane.

<4> In the above-described embodiment, the LED element 3 has been described as forming the electrode 21 on the same side as the light-emitting region 22. However, the electrode may be formed on the surface opposite to the light-emitting region 22. Even in this case, it is possible to generate a distribution of luminance in the plane of the light-emitting region 22 in response to the position of the electrode and the distance from the electrode. Such a distribution of luminance is similar to that of the LED elements 3 as long as the LED elements 3 are manufactured in the same design. Therefore, the same problem occurs when the light beams emitted from the respective LED elements 3 are arranged in parallel and then collected.

Therefore, even when the light source unit 2 has the LED element 3 in which a plurality of electrodes are formed on the surface opposite to the light-emitting region 22, the light emitted from the light source unit 2 can be utilized without being made by the first optical system 5. After the divergence angle is reduced in parallel, the light is collected by the second optical system and incident on the optical device optical system 8 disposed at the position of the focal point 7f of the second optical system 7 to be emitted by the optical system 8 of the optical device. On the entry surface, the image of the LED element 3 is visualized in a "blurred" state, so that the effect of mitigating unevenness in brightness on the incident surface of the optical unit 8 of the illuminator can be obtained.

1‧‧‧Light source device

2‧‧‧Light source department

3‧‧‧LED components

3a, 3b‧‧‧ image of LED components

5‧‧‧First Optical System

6‧‧‧ lens

7‧‧‧Second Optics

7f‧‧‧The focus of the second optical system

8‧‧‧Enlightrator optical system

10‧‧‧fly glasses

10a‧‧‧Injection surface of fly glasses

10b‧‧‧The image of the outer surface of the fly glasses

11‧‧‧ optical axis

13‧‧‧Injection area of light

14‧‧‧ lead

15‧‧‧The location of the image of the LED

21‧‧‧Electrode (non-illuminated area)

21b‧‧‧Image of electrode (non-lighting area)

22‧‧‧Lighting area

22b‧‧‧Image of the illuminated area

30‧‧‧Cylindrical optical integrator

30a‧‧‧Injection surface of cylindrical optical integrator

30b‧‧‧The exit surface of the cylindrical optical integrator

Fig. 1 is a view showing an example of an optical system of a light source device. [Fig. 2] A schematic plan view of an LED element. FIG. 3A is a view showing a view of an image of a light incident surface of a fly spectacles when the focus of the LED element is applied to the fly glasses. [Fig. 3B] Only the regions of the fly glasses are extracted from Fig. 3A to reveal the drawings. [Fig. 3C] The mode reveals a view of the image of the image on the illuminated surface when the focus of the LED element is matched to the fly glasses. [Fig. 3D] The mode reveals a picture of the image on the illuminated surface when the focus of the LED element deviates from the fly glasses. [Fig. 4] The mode reveals a plane of light emitted from one LED element. Fig. 5 is a view showing a view of an optical system of a light source device according to another embodiment. Fig. 6 is a view showing a view of an optical system of a light source device according to another embodiment.

Claims (3)

A light source device comprising: a light source unit including a plurality of LED elements; and a first optical system that prevents light rays emitted from the light source unit from collimating and narrowing a divergence angle; and the second optical system is configured to be from the first The light emitted from the optical system is condensed; and the optical system of the concentrator is disposed at a focal position of the second optical system. The light source device according to claim 1, wherein the LED element has a light-emitting surface and a linear electrode provided to face the light-emitting surface on a side opposite to the first optical system The maximum radiation angle of the light emitted from the center point of the LED element is θ ₁ , the light collecting angle after the light is emitted from the second optical system is θ ₂ , and the width of the electrode is set to d ₁ , When the length of the optical axis orthogonal to the optical axis after the light beam is emitted from the second optical system is L ₁ , the first optical system is adjusted so that the value of L ₁ satisfies the formula (1) described later. The position of the aforementioned second optical system, The light source device according to the first or second aspect of the invention, wherein the optical system of the concentrator is configured by fly spectacles in which a plurality of lenses are arranged in a matrix.