JP2011250028A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device that emits light of desired chromaticities with high chromatic uniformity.SOLUTION: A light source device includes: a cylindrical translucent tube; a circuit board arranged inside the translucent tube so as to extend along length of the translucent tube; and a plurality of LED elements aligned on the circuit board along length of the circuit board. On an outer circumferential surface of the translucent tube, a reflector is provided that has an opening which extends along the length of the translucent tube. A phosphor layer is provided so as to extend either over an entire circumferential region of an inner circumferential surface of the translucent tube, as a whole or excluding part of it, or in between the translucent tube and the reflector. Alternatively, the reflector is provided on the inner circumferential surface of the translucent tube, and the phosphor layer is provided so as to extend over an entire circumferential region, as a whole or excluding part of it, of at least one of an inner circumferential surface of the reflector and an inner circumferential surface of a portion of the translucent tube that faces the opening of the reflector.

Description

  The present invention relates to a light source device used as a light source for reading a document in devices such as a facsimile, a copying machine, and a scanner.

In recent years, for example, in a document reading apparatus such as a facsimile, a copying machine, an image reader, and a barcode reader, a light source device including an LED that emits white light has been used.
As shown in FIG. 9, a certain type of light source device 50 having such LEDs includes a plurality of LEDs 55 arranged at predetermined intervals in the longitudinal direction of the substrate 51, a plurality of LEDs 55, and a document placement. A light guide 58 made of a plate-like transparent material, which is arranged so that one end surface thereof faces the LED 55 between the placement surface 60A and guides the light flux from each LED 55 to the illuminated area. Is incident from one end surface of the light guide 58, is guided while being reflected in the light guide 58, is emitted from the other end surface of the light guide 58, and reads information on the document on the document placement surface 60A. Therefore, a belt-like light irradiation region extending in the main scanning direction is formed (see, for example, Patent Document 1). In FIG. 9, 60 is a document table on which a document is placed, 65 is a CCD (light receiving element), and 61 is a reflection mirror that reflects the reflected light from the document and causes the CCD 65 to receive it.

  As shown in FIG. 10, a certain type of LED 55 used as a light source is, for example, a phosphor layer made of a transparent resin in which a chip-like blue light emitting LED element 56 is mixed with a YAG phosphor (yellow phosphor). The phosphor layer is formed by being excited by the blue light from the blue light-emitting LED element 56 (broken line) and the blue light from the blue light-emitting LED element 56, which is molded by 57 and transmitted through the phosphor layer 57. It is configured that white light is emitted by yellow light (solid line) 57 emitted (see, for example, Patent Document 2).

JP 2006-066751 A JP 2006-121555 A

However, the light emission of the blue light emitting LED element 56 has high directivity, for example, in the normal direction of the light emitting surface of the blue light emitting LED element 56, and the LED 55 having the above configuration has a mold shape by the phosphor layer 57, The light emitted in the normal direction of the light emitting surface of the blue light emitting LED element 56 has a short distance to transmit through the phosphor layer 57 and a small amount of collision with the YAG phosphor particles. The light emitted in the direction inclined with respect to the normal direction of the light emitting surface 56 has a long distance to transmit through the phosphor layer 75 and has many collisions with the particles of the YAG phosphor, so that the yellow component increases. Therefore, there is a problem that the light quantity balance between the blue light and the yellow light differs depending on the direction, and the emitted white light has a different color depending on the direction.
Further, in the LED 55 having the above-described configuration, the relative position between the blue light emitting LED element 56 and the phosphor layer 57 is determined so that the set chromaticity can be obtained at the time of manufacture. Can't get. On the other hand, for example, the CCD 65 in the document reading device has individual differences in sensitivity characteristics. Therefore, when a light source device including the LED 55 having the above-described configuration is mounted on the document reading device, the color of light emitted from the LED 55. However, it is impossible to adjust the degree of light according to the CCD 65 actually mounted on the document reading device, and it is impossible to obtain light of chromaticity according to the sensitivity characteristic of the CCD 65 after all. is there.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a light source device that can emit light of desired chromaticity with high uniformity of chromaticity. To do.

The light source device of the present invention includes a cylindrical light-transmitting tube, a substrate disposed inside the light-transmitting tube so as to extend along the longitudinal direction of the light-transmitting tube, and arranged in the longitudinal direction on the substrate. And a plurality of LED elements arranged in
A reflector having an opening extending along the longitudinal direction of the translucent tube is provided on the outer peripheral surface of the translucent tube,
A phosphor layer is provided in a region over the entire circumference in the circumferential direction of the inner circumferential surface of the translucent tube or a region excluding a part in the circumferential direction, or between the translucent tube and the reflector. It is characterized by being.

The light source device of the present invention includes a cylindrical light-transmitting tube, a substrate disposed inside the light-transmitting tube so as to extend along the longitudinal direction of the light-transmitting tube, and arranged in the longitudinal direction on the substrate. And a plurality of LED elements arranged in
A reflector having an opening extending along the longitudinal direction of the translucent tube is provided on the inner peripheral surface of the translucent tube,
At least one of the inner peripheral surface of the reflector and the inner peripheral surface of the region corresponding to the opening of the reflector of the translucent tube, or a region excluding a part in the circumferential direction. A phosphor layer is provided.

  In the light source device of the present invention, each of the LED elements is arranged so that the optical axis of the LED element is displaced from the center in the circumferential direction of the opening of the reflector. It is preferable that the LED element is arranged so that the optical axis of the LED element extends toward the reflector.

  In the light source device of the present invention, it is preferable that the substrate is configured to be held by a substrate holding member in a state where the substrate is rotatable relative to the light transmitting cylinder. .

According to the light source device of the present invention, since the phosphor layer is provided using the inner or outer peripheral surface of the light-transmitting cylinder or the inner peripheral surface of the reflector, the phosphor layer has a uniform thickness. Because the light transmitted in any direction from the LED element has the same distance through the phosphor layer, it can emit light with a high degree of chromaticity uniformity. Each of the LED elements is configured to be separated from the translucent cylinder provided with the reflector having the opening and the phosphor layer and disposed inside the translucent cylinder, so that the optical axis of the LED element is By appropriately adjusting the angle state with respect to the opening of the reflector, it is possible to easily adjust the light quantity balance between the light emitted from the LED element and the light emitted from the phosphor layer in the emitted light. Can get light of chromaticity It can be configured as a thing.
In addition, since the above effect can be obtained by one type of LED element, it is easy to adjust optical characteristics.

  Furthermore, the substrate on which the LED elements are arranged is configured to be held so as to be rotatable relative to the translucent tube, so that the chromaticity of the emitted light can be adjusted appropriately according to the purpose. Therefore, for example, when mounting on a document reading apparatus, light having a desired chromaticity according to the sensitivity characteristic of the light receiving element actually mounted on the document reading apparatus can be reliably emitted.

It is sectional drawing which shows the outline of the structure in an example of the light source device of this invention in the state cut | disconnected along the axial center of a translucent cylinder. It is sectional drawing which shows the outline of a structure of the light source device shown in FIG. 1 in the state cut | disconnected in the orthogonal | vertical direction with respect to the axial center of a translucent cylinder. It is an idea figure which shows roughly the light distribution of the LED element for demonstrating the definition of the optical axis of the LED element in this invention. In the light source device shown in FIG. 2, it is sectional drawing which shows the state by which the angle state with respect to the opening part of a reflector of the optical axis of an LED element was changed. In the light source device shown in FIG. 2, it is sectional drawing which shows the state by which the angle state with respect to the opening part of a reflector of the optical axis of an LED element was changed. It is explanatory drawing which shows the outline of the structure in the other example of the light source device of this invention, Comprising: (A) Left end view, (B) Sectional drawing shown in the state cut | disconnected along the axial center of a translucent cylinder It is. It is sectional drawing which shows the outline of the structure in the other example of the light source device of this invention in the state cut | disconnected in the orthogonal | vertical direction with respect to the axial center of a translucent cylinder. It is sectional drawing which shows the outline of the structure in the further another example of the light source device of this invention in the state cut | disconnected in the orthogonal | vertical direction with respect to the axial center of a translucent cylinder. It is sectional drawing cut | disconnected along the subscanning direction which shows the outline of a structure in an example of the conventional light source device mounted in the original reading apparatus with the illuminance distribution in the subscanning direction of a document mounting surface. It is sectional drawing which shows the outline of a structure in an example of an LED element.

1 is a cross-sectional view showing an outline of the configuration of an example of the light source device of the present invention in a state cut along the central axis of the light-transmitting cylinder, and FIG. 2 is a schematic view of the configuration of the light source device shown in FIG. It is sectional drawing shown in the state cut | disconnected in the orthogonal | vertical direction with respect to the axial center of a pipe | tube.
In the light source device 10, a long flat printed circuit board 21 on which a plurality of chip-like LED elements 20 are mounted on one surface includes a shaft of the light-transmitting cylinder 11 inside the cylindrical light-transmitting cylinder 11. Arranged to extend along the center LC.
A substrate holding member (holder) 30 is fixed to each of both ends of the light-transmitting cylinder 11 by, for example, an inorganic adhesive S filled between the inner surface thereof and the outer peripheral surface of the light-transmitting cylinder 11. The both ends of the printed circuit board 21 are inserted into through holes formed in the end wall of the board holding member 30 and are fixed by, for example, the inorganic adhesive S, and are held and fixed thereby.
For example, when mounted on the document reading device, the translucent tube 11 is placed on the document placement surface of the document table 40 at a position below the light-transmissive document table 40 on which the document is placed on the document reading device. An imaginary straight line L that extends in the main scanning direction along a plane parallel to 40A and connects, for example, a central position on the light emitting surface 20A of the LED element 20 and a central position in the circumferential direction of an opening 16 of a reflector 15 described later is an original. The document is arranged in a state inclined at a predetermined angle with respect to the document reading axis Y perpendicular to the placement surface 40A. By irradiating the document placement surface 40A with light from the light source device 10, a strip-like illumination area LA extending in the main scanning direction for reading information on the document is formed on the document placement surface 40A. The “sub-scanning direction” means a moving direction when the light source device is moved relative to the document placement surface 40A, and the “main scanning direction” is a direction perpendicular to the sub-scanning direction. The direction parallel to the document placement surface 40A is assumed.

  Each LED element 20 is, for example, a blue light emitting LED element that emits light having a peak wavelength of 380 nm to 490 nm. On one surface of the printed circuit board 21, the light emitting surface 20 </ b> A is the axis of the light-transmitting cylinder 11. Arranged in the longitudinal direction of the printed circuit board 21 (in an array) while being positioned on the center LC.

  As the translucent tube 11, a material that transmits light emitted from the LED element 20 and light emitted from the phosphor layer 25 described later is used. As such a material, for example, a resin material such as acrylic resin, A glass material such as borosilicate glass can be exemplified.

A substantially cylindrical reflector 15 formed so that the opening 16 extends along the longitudinal direction is provided on the outer peripheral surface of the translucent tube 11, and the opening 16 of the reflector 15 in the translucent tube 11. A light emitting portion 11A is formed by a region corresponding to.
The reflector 15 is configured by winding, for example, an aluminum foil around the outer peripheral surface of the translucent tube 11, and the inner peripheral surface mirror-reflects the light from the LED element 20 and the light emitted from the phosphor layer 25. Or it is set as the reflective surface made to diffusely reflect.
Further, the opening angle α of the opening 16 of the reflector 15 around the axial center LC of the light transmitting cylinder 11 is preferably in the range of 65 ° ± 15 °, for example. When the opening angle α of the opening portion 16 is excessive, unnecessary component light is emitted and affects the CCD output. When the opening angle α of the opening portion 16 is excessively small, the light amount is insufficient and the irradiation width is insufficient. There is an influence.

In this example, the phosphor layer 25 is provided in a region extending over the entire circumference in the circumferential direction of the inner circumferential surface of the translucent tube 11.
The phosphor layer 25 emits excitation light (yellow light) having a wavelength longer than the peak wavelength of blue light due to light emission from the LED element 20 when the phosphor is excited by light from the LED element 20. A yellow phosphor is mixed in a transparent resin, or a red phosphor and a green phosphor are mixed in a transparent resin.
Examples of the yellow phosphor include (Y, Gd) ₃ Al ₅ O ₁₂ : Ce, Tb ₃ Al ₅ O ₁₂ : Ce, (Sr, Ba) Si ₂ (O, Cl) ₂ N ₂ : Eu, SrSi ₂ (O, Cl) ₂ N ₂ : Eu can be exemplified.
Examples of the red phosphor include CaAlSiN ₃ : Eu, (Ca, Sr) ₂ Si ₅ N ₈ : Eu, CaSiN ₂ : Eu, Sr ₃ SiO ₂ : Eu, Yb, Ba ₃ MgSi ₂ O ₈ : Eu, Mn (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ C ₁₂ : Eu, Mn, etc.
As the green phosphor, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, Sr—SiON: Eu, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, ZnS: Cu, Al, BaMgAl ₁₀ O ₁₇ : Eu, Mn SrAl ₂ O ₄ : Eu and the like can be exemplified.

Thus, in the light source device 10 described above, the imaginary axis connecting the optical axis C of the LED element 20, the central position in the circumferential direction of the opening 16 of the reflector 15, and the central position of the light emitting surface 20 </ b> A of the LED element 20. The angle β (hereinafter referred to as “LED element arrangement angle”) β formed with respect to the straight line L is adjusted so that light having a desired chromaticity corresponding to the purpose is emitted.
The light emission of the LED element 20 has a light distribution as shown in FIG. 3, and has high directivity in the normal direction of the light emitting surface 20 </ b> A of the LED element 20. In the present invention, the direction in which the amount of light in the light distribution is maximized, that is, the axis extending in the normal direction at the center position of the light emitting surface 20A of the LED element 20, is defined as the optical axis C of the LED element 20. .

In this example, each of the LED elements 20 is positioned such that the intersection of the optical axis C of the LED element 20 and the outer peripheral surface of the translucent tube 11 is displaced from the center position in the circumferential direction of the opening 16 of the reflector 15. Specifically, the LED element 20 is arranged so that the optical axis C of the LED element 20 extends toward the reflector 15, and is emitted in a relatively large amount of light including the optical axis direction of the LED element 20. Of the light, the blue light transmitted through the phosphor layer 25 is reflected by the reflector 15 and returned to the LED element 20 side to be used for excitation of the phosphor, which is also shown in the results of experimental examples described later. As shown in FIG. 4, that is, the configuration in which the optical axis C of the LED element 20 is positioned at the center position in the circumferential direction of the opening 16 of the reflector 15 (LED element arrangement angle β = 0 °). White with a small proportion of blue light compared to Color light is emitted.
Further, as shown in FIG. 5, an imaginary straight line L connecting the optical axis C of the LED element 20, the center position in the circumferential direction of the opening 16 of the reflector 15 and the center position of the light emitting surface 20 </ b> A of the LED element 20. As shown in the result of an experimental example to be described later, the angle β (hereinafter referred to as “LED element arrangement angle”) β is made larger than that of the configuration shown in FIG. Further, white light with a small proportion of blue light is emitted.
That is, as the LED element arrangement angle β increases, the ratio of the amount of blue light in the emitted light decreases.

The light source device 10 can be manufactured as follows.
That is, first, the phosphor layer 25 is formed with a predetermined thickness by applying a turbid liquid in which the phosphor is turbid in the resin material to the inner peripheral surface of the light-transmitting cylinder 11 provided with the reflector 15 on the outer peripheral surface. Thereafter, a printed circuit board 21 on which a plurality of LED elements 20 are mounted is inserted into the translucent tube 11, and the light emitting surface 20 </ b> A of each LED element 20 is positioned on the axial center LC of the translucent tube 11. In this state, the light transmission tube 11 is temporarily fixed by being held by appropriate jigs that are rotatably provided to the light transmission tube 11 at both ends.
Next, each LED element 20 is turned on, and a photometric operation is performed in which the emitted light is detected by a spectroscope disposed at a position 3 cm away from the outer peripheral surface of the light emitting portion 11A of the light transmitting tube 11 to measure chromaticity. Based on this result, the photometric operation for measuring the chromaticity again by adjusting the angle state of the optical axis C of the LED element 20 with respect to the opening 16 of the reflector 15 by rotating the jig is performed as necessary. The angle state (LED element) for obtaining emitted light of desired chromaticity, for example, when it is mounted on a document reading device, to obtain emitted light of chromaticity corresponding to the sensitivity characteristic of the light receiving element (CCD) A setting condition for the arrangement angle β) is acquired.
Thereafter, both ends of the printed circuit board 21 are inserted into through holes formed in the end wall of the board holding member 30, and fixed to the end wall of the board holding member 30 by the inorganic adhesive S, and held on this. The substrate holding member 30 is filled with the inorganic adhesive S between the inner peripheral surface of the substrate holding member 30 and the outer peripheral surface of the translucent tube 11 with the printed circuit board 21 disposed under the setting conditions acquired above. Is fixed to the light-transmitting tube 11, the light source device 10 having the configuration shown in FIGS. 1 and 2 can be obtained.

Thus, according to the light source device 10 configured as described above, since the phosphor layer 25 is provided on the inner peripheral surface of the light-transmitting cylinder 11, the phosphor layer 25 is highly uniform in thickness. The light emitted from the LED element in any direction has the same distance through the phosphor layer, so that light having a high degree of chromaticity can be emitted, and each LED element 20 can be emitted. Is separated from the translucent tube 11 provided with the reflector 15 having the opening 16 and the phosphor layer 25, and is disposed inside the translucent tube 11. By appropriately adjusting the angle state of the axis C with respect to the opening 16 of the reflector 15, the light quantity balance between the light emitted from the LED element 20 and the light emitted from the phosphor layer 25 in the emitted light can be easily adjusted. So you can It may be configured as being capable of obtaining a light Nozomu chromaticity.
In addition, since the above effect can be obtained by one type of LED element 20, adjustment of optical characteristics is easy.

  Furthermore, since the optical axis C of the LED element 20 is arranged so as to extend toward the reflector 15, fluorescence of light emitted in a relatively large amount of light including the direction of the optical axis C of the LED element 20. The blue light transmitted through the body layer 25 is reflected by the reflector 15 and returned again to the LED element 20 side to be used for excitation of the phosphor, so that light emitted from the light emitting portion 11A (white light) ) Has a low direction dependency due to the light distribution of the LED element 20 itself, and the chromaticity uniformity in the light irradiation region can be further increased. Therefore, for example, when used as a light source of a document reading apparatus, it is possible to reliably prevent a reading failure due to the light receiving element.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.

  In the above example, the chromaticity is adjusted by appropriately adjusting the angle state of the optical axis C of the LED element 20 with respect to the opening of the reflector 15 when the light source device 10 is manufactured, and the LED element 20 is mounted. Although the board holding member 30 that holds the circuit board 21 is fixed to the light-transmitting cylinder 11, the printed circuit board 21 can rotate relative to the light-transmitting cylinder 11 as shown in FIG. 6. It is preferable to have a held configuration. In the light source device 10 of this example, the holding structure of the printed circuit board 21 at the left end and the right end is the same.

The holding structure of the printed circuit board 21 will be described in detail. The printed circuit board 21 has rod-like portions 22 that extend continuously outward at both ends in the longitudinal direction, and this rod-like portion. 22 is inserted into a through-hole 31 formed in the end wall of the substrate holding member 30 and is pivotally supported by the substrate holding member 30 so as to protrude outwardly from the outer end surface of the substrate holding member 30 and extend. Further, a cylindrical angle adjusting rotator (rotary knob) 35 is provided at the center axis (rotary knob) 35 at the outer end of the rod-shaped portion 22 of the printed circuit board 21 that protrudes outward from the outer end surface of the board holding member 30. The rotation center axis R) is fitted and mounted, for example, in a state of being coaxial with the axis center LC of the light-transmitting cylinder 11.
A fixing screw 36 is provided on the outer peripheral edge of the angle adjusting rotator 35 so as to extend through the angle adjusting rotator 35 in the thickness direction. By tightening the fixing screw 36, the angle adjusting rotator 35 is tightened. A lock mechanism that prohibits the rotation of the rotating body 35 and fixes the angle state (LED element arrangement angle β) of the printed circuit board 21 is configured.

  In the light source device 10, first, in a state where the printed circuit board 21 is fixed at a predetermined angle with respect to the translucent tube 11, each LED element 20 is turned on, and the light emitting portion 11 </ b> A of the translucent tube 11 is turned on. A photometric operation is performed in which the emitted light is detected by a spectroscope disposed at a position 3 cm away from the outer peripheral surface of the lens and the chromaticity is measured. Based on the detection result, the left end side fixing screw 36 and the right end side fixing are fixed. The printed circuit board 21 is rotated about the rotation center axis R by loosening the screws and rotating the angle adjusting rotator 35 in the same direction, and the opening 15 of the reflector 15 on the optical axis C of the LED element 20. The photometric operation for adjusting the angle state and measuring the chromaticity again is performed as necessary, and when the emitted light of the desired chromaticity is obtained, the fixing screw 36 on the left end side and the fixing on the right end side are fixed. Screw for both Shimete by fixing the angular position of the printed circuit board 21 (LED element arrangement angle beta), it is possible to adjust the chromaticity of the emitted light.

  According to the light source device 10 having such a configuration, the angle state of the optical axis C of the LED element 20 with respect to the opening 16 of the reflector 15 is adjusted to appropriately adjust the chromaticity of the emitted light according to the purpose. Therefore, for example, when mounting on a document reading apparatus, light having a desired chromaticity according to the sensitivity characteristic of the light receiving element actually mounted on the document reading apparatus can be reliably emitted.

Furthermore, in the present invention, the phosphor layer is not limited to a configuration in which the phosphor layer is provided in a region extending over the entire circumference in the circumferential direction of the inner peripheral surface of the translucent tube. For example, as shown in FIG. 25 is provided in a region excluding a part in the circumferential direction of the inner peripheral surface of the translucent tube 11, specifically, for example, in a region excluding the central portion in the circumferential direction of the region corresponding to the opening of the reflector 15. It may be configured. According to such a configuration, the amount of light emitted from the light source device 10 can be increased.
Furthermore, in the configuration in which the reflector is provided on the outer peripheral surface of the light-transmitting cylinder, the phosphor layer may be provided between the light-transmitting cylinder and the reflector.
Furthermore, as shown in FIG. 8, the reflector 15 may be configured to be provided on the inner peripheral surface of the translucent tube 11, and in such a configuration, the phosphor layer 25 includes at least A region excluding a region over the entire circumference in the circumferential direction or a portion in the circumferential direction of at least one of the inner circumferential surface of the reflector 15 and the inner circumferential surface of the region corresponding to the opening 16 of the reflector 15 of the light transmitting tube 11. In addition, it may be formed. In this example, the phosphor layer 25 is provided in a region over the entire circumference in the circumferential direction of the inner peripheral surface of the reflector 15 and the inner peripheral surface of the region corresponding to the opening 16 of the reflector 15 in the light transmitting tube 11. It has been.

  Furthermore, when a high input type LED element 20 is used, for example, a configuration in which the printed circuit board 21 is provided with a heat sink function by configuring the printed circuit board 21 with a member having good heat conduction. Alternatively, the heat sink may be provided on the other surface side of the printed circuit board 21.

Hereinafter, experimental examples performed for confirming the effects of the present invention will be described.
<Experimental example 1>
According to the configuration shown in FIG. 1 and FIG. 2, the reflector is provided on the outer peripheral surface of the light-transmitting tube and the phosphor layer is provided over the entire inner peripheral surface of the light-transmitting tube, and the LED element arrangement angle (β) 7 types of light source devices (A) to (G) according to the present invention were prepared according to Table 1 below. Specific configurations of the light source devices (A) to (G) are as follows.
A chip-like blue light-emitting LED element was used as the LED element (20). The number of LED elements (20) is 13, and the arrangement pitch of LED elements (20) (a separation distance between adjacent LED (20) elements) is 20 mm.
The translucent tube (11) is made of borosilicate glass, has a total length of 100 mm, an inner diameter of 8.8 mm, and a wall thickness of 0.5 mm.
The reflector (15) is formed by winding an aluminum foil so that the opening (16) is formed on the outer peripheral surface of the light transmitting cylinder (11), and the opening angle (α) of the opening (16). Is 65 °. A YAG phosphor (yellow phosphor) was used as the phosphor constituting the phosphor layer (25), and the thickness of the phosphor layer (25) was 20 μm.

  About each of light source device (A)-(G), the center position in the light-projection surface (20A) of a LED element (20) from the outer peripheral surface of the opening part area | region of a reflector (15) of a translucent cylinder (11). And a light receiving unit of the chromaticity measuring device at a position separated by 30 mm in a virtual straight line (L) direction connecting the central portion in the circumferential direction of the opening (16) of the reflector (15). ) To (G), the x-coordinate value and the y-coordinate value of the chromaticity of the emitted light were obtained. The results are shown in Table 1 below. In the case of an achromatic color (white light), the x coordinate value and the y coordinate value are x = 0.33 and y = 0.33, respectively.

  As is clear from the results shown in Table 1, it was confirmed that the blue component of the emitted light from the light source device decreases as the LED element arrangement angle (β) increases.

DESCRIPTION OF SYMBOLS 10 Light source device 11 Translucent cylinder 11A Light emission part 15 Reflector 16 Opening part 20 LED element 20A Light emission surface 21 Printed circuit board 22 Rod-shaped part 25 Phosphor layer 30 Substrate holding member (holder)
31 Through hole 35 Rotating body for angle adjustment (rotary knob)
36 Fixing screw 40 Document table 40A Document placement surface C Optical axis of LED element L Virtual straight line LA Illumination area LC Center of axis of translucent tube R Rotation center axis S Inorganic adhesive Y Document reading axis α Reflector opening Opening angle β LED element arrangement angle 50 Light source device 51 Substrate 55 LED
56 Blue light-emitting LED element 57 Phosphor layer 58 Light guide body 60 Document table 60A Document placement surface 61 Reflecting mirror 65 CCD (light receiving element)

Claims (5)

A cylindrical translucent tube, a substrate disposed inside the translucent tube along the longitudinal direction of the translucent tube, and a plurality of LEDs arranged side by side in the longitudinal direction on the substrate With elements,
A reflector having an opening extending along the longitudinal direction of the translucent tube is provided on the outer peripheral surface of the translucent tube,
A phosphor layer is provided in a region over the entire circumference in the circumferential direction of the inner circumferential surface of the translucent tube or a region excluding a part in the circumferential direction, or between the translucent tube and the reflector. A light source device characterized by comprising: A cylindrical translucent tube, a substrate disposed inside the translucent tube along the longitudinal direction of the translucent tube, and a plurality of LEDs arranged side by side in the longitudinal direction on the substrate With elements,
A reflector having an opening extending along the longitudinal direction of the translucent tube is provided on the inner peripheral surface of the translucent tube,
At least one of the inner peripheral surface of the reflector and the inner peripheral surface of the region corresponding to the opening of the reflector of the translucent tube, or a region excluding a part in the circumferential direction. A light source device provided with a phosphor layer.   3. Each of the LED elements is disposed so that the optical axis of the LED element is displaced from the center in the circumferential direction of the opening of the reflector. The light source device according to 1.   Each of the said LED element is arrange | positioned so that the optical axis of the said LED element may extend toward the said reflector, The light source device of Claim 3 characterized by the above-mentioned.   The said board | substrate is hold | maintained by the board | substrate holding member in the state by which the said board | substrate was able to rotate relatively with respect to the said translucent cylinder, The Claim 1 thru | or 4 characterized by the above-mentioned. Light source device.

Images