JP2013093190A - Light source device and lighting device using the light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device with a simple structure and taking little time and efforts for manufacturing, as well as a lighting device using the same.SOLUTION: The light source device 4 has point light sources, a reflection hood consisting of a bottom part on which the point light sources are installed, and a pair of opposed side curved parts which are installed extended to an outside direction from both opposed side parts of the bottom part and of which end parts are open, and in which the face opposed to the inner space surrounded by the bottom part and the pair of side curved parts is formed of a reflecting surface. The light source device 4 further has a light diffusion sheet provided at a position opposed to the point light sources so as to close the opening of the reflection hood formed of the open end parts of the pair of side curved parts.

Description

The present invention relates to a light source device and an illumination device using the light source device.

In recent years, lighting devices using point light sources such as LEDs (= light-emitting diodes) have emerged as light sources for reasons such as low power consumption, low flicker, durability, and long life. However, the LED generally has the maximum luminous intensity in the front optical axis direction, and has directivity characteristics in which the luminous intensity decreases as the angle with respect to the optical axis direction increases. Therefore, when using an LED as a light source for a lighting device such as a billboard that needs to obtain uniform planar illumination light, it is necessary to have a configuration that diffuses the light of the LED and uniformly illuminates the planar display surface. It becomes.

Therefore, for example, in Patent Document 1, a reflection hood having an inner wall surface formed of a reflection surface and a pair of first and second light deflection reflection plates that deflect irradiation light from a point light source in a predetermined direction are provided. The first and second light deflecting reflectors have a predetermined gap between the reflecting surface of the reflection hood and a predetermined gap between each other with an optical axis passing through a zero directivity angle of the point light source, That is, the configuration of the light source device arranged with a predetermined inclination angle α with respect to the optical axis so that the gap closer to the point light source is larger and the gap closer to the point light source is smaller is shown. Has been.
Japanese Patent No. 4528911

However, in the light source device of Patent Document 1, the gap between the pair of first and second light deflection reflectors closer to the point light source is larger and the gap between the first light deflection reflector and the second light deflection reflector is smaller. Thus, since each of the optical axes is arranged at a predetermined inclination angle α, the configuration of the light source device becomes complicated, and the production of the light source device is difficult and troublesome.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a light source device that has a simple configuration and that does not require time and effort to manufacture, and an illumination device that uses the light source device.

In order to achieve the object, in the invention of claim 1, a point light source,
A bottom portion on which the point light source is provided; and a pair of opposed side curved portions that extend outward from opposite sides of the bottom portion and whose ends are open, and the bottom portion and the pair of the side portions A reflective hood in which the surface facing the internal space surrounded by the curved portion is formed of a reflective surface;
The light source device is provided with a light diffusion sheet provided at a position facing the point light source so as to close the opening of the reflective hood formed by the open ends of the pair of side curved portions.

According to a second aspect of the present invention, a light source device according to the first aspect is provided, wherein a spacer is provided between the bottom portion and the light diffusing sheet so as to maintain a distance therebetween.

According to a third aspect of the present invention, the light reflecting device according to the first or second aspect is configured such that the reflective hood has a high reflectance and is formed of a reflective material that diffusely reflects.

According to a fourth aspect of the present invention, there is provided the light source device according to the third aspect, wherein the reflective hood is made of an ultrafine foamed reflective material.

In the invention of claim 5, a substrate having a point light source is attached to the back of the channel of a substantially channel-type attachment member attached to the lighting device, and the light diffusion sheet is closed so as to close the opening near the opening of the channel. It was set as the light source device which attached.

According to a sixth aspect of the present invention, the light diffusing sheet is a light source device according to any one of the first to fifth aspects, wherein a plurality of through holes are provided at substantially the center in the width direction with a space therebetween.

The light source device according to any one of claims 1 to 5, wherein the light diffusion sheet is provided with a slit along a longitudinal direction of the light diffusion sheet at a substantially central portion in the width direction. It was.

According to an eighth aspect of the present invention, the light source device according to any one of the first to seventh aspects, wherein the point light source is one or a plurality of light emitting diodes or laser diodes.

According to a ninth aspect of the present invention, two rectangular first and second light diffusing members are arranged to face each other with a predetermined gap therebetween, and at least one end side of the first and second light diffusing members. The light source device according to any one of claims 1 to 8 is disposed in the gap.

In the invention of claim 10, the rectangular light diffusing member and the reflecting member having a high reflectance are arranged to face each other with a predetermined gap, and the gap between at least one side of the light diffusing member and the reflecting member is It was set as the illuminating device by which the light source device in any one of Claims 1-8 is arrange | positioned.

In the invention of claim 11, the light diffusing member has a light reflectance that is higher on the side closer to the point light source, and decreases as the distance from the point light source decreases, and the light transmittance is lower on the side closer to the point light source. The lighting device according to claim 8, wherein the lighting device increases as the distance from the light source increases.

According to invention of Claims 1-11, the bottom part in which a point light source is provided, and a pair of opposing side curved part which was extended outward from the both sides which the said bottom part opposes, and the edge part was open | released. A reflective hood having a reflective surface with a surface facing the inner space surrounded by the bottom portion and the pair of side curved portions formed by a reflective surface, and formed by open ends of the pair of side curved portions. From a point light source with strong directivity, such as a light-emitting diode, by using a light source device that covers the opening of the reflective hood and is provided with a light diffusion sheet at a position facing the point light source. The emitted light is reflected a plurality of times between the light diffusion sheet and the reflection surface of the reflection hood, and then passes through the light diffusion sheet and is emitted to the outside. Therefore, even if a point light source is used, the light can be dispersed and emitted from the light source device without concentrating the light on a specific location. In addition, the configuration of the light source device is simple, and it is convenient because it does not take time to manufacture.

In particular, according to the invention of claim 2, since the spacer is provided between the bottom portion where the point light source is disposed and the light diffusion sheet, the distance between the point light source and the light diffusion sheet changes. Therefore, the predetermined interval can be maintained, and the light from the point light source can be appropriately dispersed by the light diffusion sheet.

In particular, according to the invention of claim 3, the light from the point light source can be efficiently reflected, and the light utilization rate can be increased.

In particular, according to the fourth aspect of the present invention, since the reflective hood is made of an ultra-fine foam reflective material, the material is easily obtained and the processing becomes easy.

In particular, according to the invention of claim 5, since the light diffusion sheet is directly attached to the attachment member for attaching the light source device to the illuminating device, it is very easy to manufacture the light source device. Easy to install on.

In particular, according to the inventions of claims 6 and 7, the light diffusing sheet is provided with through holes or slits, so that the light from the highly directional point light source can be dispersed without being concentrated at a specific location. And the amount of light emitted from the light source device can be adjusted.

In particular, according to the invention of claim 8, since the light source diode or the laser diode is used as the point light source, power consumption and flickering are reduced, and the durability of the point light source is enhanced.

In particular, according to the inventions of claims 9 to 11, a light guide plate required in a conventional bulletin board or the like is not necessary, and it is possible to reduce the weight and price of the lighting device. Moreover, uniform planar illumination light can be obtained over the entire display surface of an illumination device such as a bulletin board.

In particular, according to the invention of claim 10, since the light diffusing member is disposed on one surface of the lighting device and the reflecting member is disposed on the other surface, the lighting device is used for a lighting device or the like in which only one surface is a display surface. Can be convenient.

In particular, according to the invention of claim 11, the light reflectance is high on the side close to the point light source, such as by sticking a transmission diffusion film to the inner side surface of the light diffusing member, and decreases as the distance from the point light source increases. In addition, by configuring the light diffusing member so that the light transmittance is low on the side close to the point light source and increases as the distance from the point light source increases, the light transmittance is more uniform over the entire display surface of the lighting device such as a billboard. Planar illumination light can be obtained.

The present invention includes a point light source, a bottom portion on which the point light source is provided, and a pair of opposed side curved portions that are extended outward from opposite sides of the bottom portion and open at the ends. The reflective hood in which the surface facing the inner space surrounded by the bottom portion and the pair of side curved portions is formed by a reflective surface, and the open ends of the pair of side curved portions is formed. Even if a highly directional point light source such as a light-emitting diode is used, a light diffusing sheet is provided at a position facing the point light source so as to block the opening of the reflective hood, so that light can be emitted. The light can be distributed and emitted from the light source device without being concentrated at a specific location.

FIG. 1 is a perspective view illustrating the entire lighting device 1 as an example, and FIG. 2 is a cross-sectional view of the lighting device 1 taken along line AA in FIG. The illuminating device 1 is an illuminating device that is used as, for example, a bulletin board at a railway platform, and is a frame-shaped frame mainly composed of a pair of opposed long side frames 2a and 2b and short side frames 2c and 2d. 2 and a rectangular display panel 3 having long sides and short sides facing each other and fitted into the front and rear opening surfaces of the frame body 2 are formed into a thin box shape.

The illumination device 1 is provided with a light source device 4 along a long side frame 2a inside the box shape. A transmission diffusion film 5 is attached to the inner side surface of each display panel 3.

The frame 2 is made of metal such as aluminum. The display panel 3 has a guide display printed on the outer surface, and is made of, for example, a translucent glass plate or a synthetic resin that transmits light emitted from the inside of the lighting device 1 and constitutes a light diffusion member.

As shown in FIGS. 3 to 6, the light source device 4 includes a substrate 7 provided with a plurality of point light sources 6, a reflective hood 8, a spacer 9, a light diffusion sheet 10, and a screw 11 nut 24. 3 is a cross-sectional view showing the location of the point light source 6 in the light source device 4, and FIG. 4 is a cross-sectional view showing the location of the spacer 9 in the light source device 4. FIG. 5 is an exploded view showing components of the light source device 4, and FIG. 6 is a bottom view of the light source device 4. FIG. 7 is a plan view of the light source device 4.

The point light source 6 is, for example, one or a plurality of light emitting diodes or laser diodes that emit light upon receiving power supply, and is placed on the substrate 7 in accordance with a fitting hole (described later) of the reflective hood 8. They are arranged in a line at substantially equal intervals. Thus, if the light source diode or the laser diode is used as the point light source 6, power consumption and flickering are reduced, and the durability of the point light source 6 is enhanced.

Furthermore, it is good also as a structure which attaches the lens for collecting light to the light emitting diode used as the point light source 6, or the light emission part of a laser diode. Note that light emitting diodes and laser diodes generally have a directional characteristic in which the luminous intensity in the front optical axis direction is maximum and the luminous intensity decreases as the angle with respect to the optical axis direction increases. As shown in FIG. 2, the substrate 7 is fixed under the long side frame 2 a of the frame 2 using a substantially channel-type attachment member 15.

The reflective hood 8 has a bottom portion 12 provided with a plurality of fitting holes (not shown), and a pair of opposing lateral sides that extend outward from opposite sides of the bottom portion 12 and are open at the ends. It has a curved portion 13 and has a substantially semicircular cross section. Further, a surface facing the internal space surrounded by the bottom portion 12 and the pair of side curved portions 13 is formed by the reflective surface 14. Further, the point light sources 6 are fitted into the fitting holes of the reflective hood 8 so that the light emitting portions are exposed.

The reflection hood 8 plays a role of reflecting the irradiation light from the point light source 6 in a predetermined direction. Therefore, it is desirable that the reflection surface 14 of the reflection hood 8 has a low light absorption rate, a high reflection rate, and a material that reflects irregularly as well as total reflection. Thus, by setting it as the structure which uses the reflective hood 8, the light from the point light source 6 can be reflected efficiently, and the utilization factor of light can be raised.

Specifically, for example, the reflective hood 8 is formed of an ultrafine foamed light reflecting material, and is formed of an ultrafine foamed light reflecting material having characteristics of a light transmittance of 1%, a reflectance of 98%, and an absorbance of 1%. It is desirable. If a configuration using an ultrafine foamed light reflecting material is used, it is easy to obtain the material and the processing is easy.

The spacer 9 is for maintaining the space | interval of the point light source 6 and the light-diffusion sheet 10, for example, is metal, such as aluminum.

The light diffusion sheet 10 has high light diffusibility without impairing light transmittance. For example, it is desirable that the light diffusion rate of the light diffusion sheet 10 is 90% or more. When the light diffusing sheet 10 is irradiated with light from the point light source 6, the light diffusing sheet 10 reflects a part of the light and transmits the other part, diffuses the light and irradiates the outside. The term “sheet” of the light diffusing sheet 10 is a concept including paper and plate-like ones, and the light diffusing sheet 10 may be composed of either of them.

Next, a method for assembling the light source device 4 will be described with reference to FIG. The spacer 9 is screwed with a nut 24 while the reflective hood 8 is sandwiched through the through holes 28 of the substrate 7 in which the point light sources 6 are arranged in a row. Then, the screw 11 is screwed into the screw hole 25 provided at the lower end of the spacer 9 while the light diffusion sheet 10 is sandwiched through the through hole 26. And as above-mentioned, the board | substrate 7 of the assembled light source device 4 is fixed under the long side frame 2a of the frame 2 using the attachment member 15 (refer FIG. 2). Thus, since the spacer 9 is provided between the point light source 6 and the light diffusion sheet 10, the predetermined distance is maintained without changing the distance between the point light source 6 and the light diffusion sheet 10. The light from the point light source 6 can be appropriately dispersed by the light diffusion sheet 10. Further, the configuration of the light source device 4 is simple and convenient because it does not take time to manufacture.

The transmission diffusion film 5 has the same shape as the display panel 3 as shown in FIG. 8, and is attached to the inner surface of the display panel 3 of the lighting device 1 as shown in FIG. The transmissive diffusion film 5 is formed of a member having a diffusivity for irregularly reflecting received light, a predetermined light transmittance / light reflectance, and a low light absorption rate. The transmissive diffusion film 5 is configured such that the light reflectance and the light transmittance are different depending on the distance from the point light source 6 of the light source device 4. Specifically, as shown in FIG. 9, the transmissive diffusion film 5 includes a light transmissive film 16 and a plurality of reflective dots 17 disposed on the film 16 with a predetermined regularity. ing. Each reflective dot 17 is made of a reflective material having a high reflectance, and has a predetermined shape. The reflective dots 17 are formed so that the area close to the point light source 6 has a large area, the intermediate area has a medium area, and the area far from the point light source 6 has a small area. For this reason, the light reflectance is high at locations close to the point light source 6 of the light source device 4, and gradually decreases as the distance from the point light source 6 increases. On the other hand, the light transmittance is low at locations close to the point light source 6 and gradually increases as the distance from the point light source 6 increases.

Thus, if it is set as the structure using the display panel 3 and the permeation | transmission diffusion film 5, the light-guide plate required by the conventional bulletin board etc. becomes unnecessary, and it can aim at the weight reduction and price reduction of the illuminating device 1. FIG. It becomes. Further, more uniform planar illumination light can be obtained over the entire display surface of the lighting device 1 such as a bulletin board.

In the present embodiment, the configuration in which the area of the reflective dot 17 is changed depending on the distance from the point light source 6 is shown, but the present invention is not limited to this configuration. For example, as shown in FIG. 10, the transmissive diffusion film 5 has a predetermined regularity on the reflective film 18 in which a reflective surface having a high reflectance is formed by printing or the like on a transparent synthetic resin film, A plurality of openings 19 having a predetermined shape may be provided. The opening 19 is provided by etching or the like and plays a role of transmitting light. The opening 19 has a small area in a region close to the point light source 6, a medium area in the intermediate region, and a large area in a region far from the point light source 6.

Next, the effect | action of the illuminating device 1 is demonstrated using FIG. Although the point light source 6 is omitted in FIG. 2, the point light source 6 is provided on the bottom 12 of the reflection hood 8. When the point light source 6 receives light from the power supply and irradiates light, the light emitted from the point light source 6 irradiates the light diffusion sheet 10 including the light reflected by the reflection surface 14 of the reflection hood 8. The light applied to the light diffusion sheet 10 is diffused by the light diffusion sheet 10 and passes through the light diffusion sheet 10. As described above, since the light from the point light source 6 is transmitted through the light diffusion sheet 10 and emitted from the light source device 4, even if a light source with strong directivity such as a light emitting diode is used as the point light source 6, the light is emitted. The light can be dispersed and emitted from the light source device 4 without being concentrated at a specific location.

And the light radiate | emitted from the light source device 4 irradiates the permeation | transmission diffusion film 5 stuck on the inner surface of each display panel 3. FIG. The light diffusing film 5 has a high light reflectance at a location near the point light source 6 of the light source device 4 and gradually decreases as the distance from the point light source 6 increases. Since the location at a short distance is low and gradually increases as the distance from the point light source 6 increases, the entire surface of each display panel 3 of the illumination device 1 can be uniformly irradiated from the inside.

In the present embodiment, the display panel 3 is provided on the front and rear opening surfaces of the frame body 2, that is, the configuration of the illumination device 1 in which the display panel 3 is provided on the front and rear is shown. However, the present invention is limited to this configuration. It is good also as a structure which is not what was provided and the display panel 3 is provided only in either one before and behind the illuminating device 1. FIG. In that case, instead of the transmissive diffusion film 5, a reflective film having a high reflectance is affixed to the inner surface facing the display panel 3 of the lighting device 1.

In the present embodiment, the configuration in which the light source device 4 is provided along the long side frame 2a is shown. However, the present invention is not limited to this configuration, and the light source device 4 is arranged in the long side frame 2b and the short side frame 2c. It is good also as a structure provided along either of 2d. For example, when the light source device 4 is provided along the short side frame 2c, the light reflectance is high at a location near the point light source 6 of the light source device 4 as shown in FIG. The transmissive diffusion film 5 is disposed so that the light transmittance gradually decreases with increasing distance, while the light transmittance is low at locations close to the point light source 6 and gradually increases with distance from the point light source 6. That is, the transmissive diffusion film 5 includes a light transmissive film 21 and a plurality of reflective dots 22 arranged on the film 21 with a predetermined regularity. The reflective dots 22 are made of a reflective material having a high reflectance and have a predetermined shape. The reflective dots 22 are formed such that the area close to the point light source 6 has a large area, the intermediate area has a medium area, and the area far from the point light source 6 has a small area.

In the present embodiment, the configuration in which the reflective hood 8 is concavely curved is shown. However, the reflective hood 8 is not necessarily curved, and may be configured to be polygonally bent to provide a concave portion.

In the present embodiment, the configuration in which the light diffusing sheet 10 is convexly curved with respect to the reflective hood 8 is shown. However, the configuration is not limited to this configuration, and the open end of the side curved portion 13 is used. What is necessary is just the structure provided in the position facing the point light source 6 so that the opening part of the reflective hood 8 formed may be plugged up. Therefore, for example, as shown in FIG. Further, for example, as shown in FIG. 13, the light diffusion sheet 10 may be configured to be flat and not curved.

Furthermore, as shown in FIGS. 14 and 15, a plurality of through holes may be provided at a substantially central portion in the width direction of the light diffusion sheet 10 at intervals. Or as shown in FIG. 16, it is good also as a structure by which the slit along the longitudinal direction of the light-diffusion sheet 10 is provided in the approximate center part of the width direction of the light-diffusion sheet 10. As shown in FIG. In this way, by providing the light diffusing sheet 10 with through holes or slits, the light from the highly directional point light source 6 can be dispersed and emitted from the light source device 4 without being concentrated at a specific location. In addition, the amount of light emitted from the light source device 4 can be adjusted.

Moreover, as shown in FIG. 17, it is good also as a structure which provides the prism-shaped reflective member 27 of a cross-sectional triangle prism shape or a semicircle in cross section along the long side frame 2b so that the light source device 4 may be opposed. With such a configuration, the light emitted from the light source device 4 and reaching the long side frame 2 b is reflected by the reflecting member 27. Therefore, the light to the display panels 3 on both sides increases, and the light utilization rate can be increased.

Further, in this embodiment, the light source device 4 including the substrate 7 provided with a plurality of point light sources 6, the reflective hood 8, the spacer 9, the light diffusion sheet 10, the screw 11, and the nut 24 is assembled and used. Although the configuration is shown, the present invention is not limited to this configuration. For example, a point light source 6 is disposed along the long side frame 2a, and light is emitted at a predetermined interval so as to face the point light source 6. It is good also as a structure which fixes the diffusion sheet 10 in the illuminating device 1. FIG. In this case, the reflective hood 8 is not provided.

As an example in which the reflective hood 8 is not provided, as shown in FIG. 18, a substrate 7 having a point light source 6 is attached to the cross-section channel type attachment member 15 in the same manner as in the first embodiment. The light diffusing sheet 10 may be attached to the lower step portion 15a near the channel opening of the mounting member 15 so as to close the channel opening.

Thereby, the light of the point light source 6 is diffused by the light diffusion sheet 10 and irradiated from the light source device 4 and reaches the display panels 3 on both sides. Further, in this case, the configuration of the light source device 4 is simple, the number of parts is small, and the attachment to the illumination device is easy.

It is a perspective view which shows the whole illuminating device of Example 1 which concerns on this invention exemplarily. It is sectional drawing which cut | disconnected the illuminating device of Example 1 which concerns on this invention by the AA line. It is sectional drawing which shows the arrangement | positioning location of the point light source in the light source device of Example 1 which concerns on this invention. It is sectional drawing which shows the arrangement | positioning location of the spacer of the light source device of Example 1 which concerns on this invention. It is the exploded view which showed the component of the light source device of Example 1 which concerns on this invention. It is a bottom view of the light source device 4 of Example 1 which concerns on this invention. It is a top view of the light source device 4 of Example 1 which concerns on this invention. It is explanatory drawing which shows the display panel and transmission diffusion film of Example 1 which concern on this invention. It is explanatory drawing which shows the structure of the permeation | transmission diffusion film of Example 1 which concerns on this invention. It is explanatory drawing which shows the structure of the transmission diffusion film of another Example which concerns on this invention. It is explanatory drawing which shows the structure of the transmission diffusion film of another Example which concerns on this invention. It is sectional drawing which shows the structure of the reflective hood of the light source device of another Example which concerns on this invention. It is sectional drawing which shows the structure of the reflective hood of the light source device of another Example which concerns on this invention. It is a top view which shows the structure of the light-diffusion sheet | seat of another Example which concerns on this invention, (a) A figure shows that each through-hole is a rectangular shape, (b) A figure shows that each through-hole is a circular shape. . It is sectional drawing which shows the structure of the light source device of another Example which concerns on this invention. It is a top view which shows the structure of the light-diffusion sheet | seat of another Example which concerns on this invention. It is sectional drawing which shows the structure of the illuminating device of another Example which concerns on this invention, (a) A figure has a prism shape in which a reflecting member is a cross-sectional triangle, (b) A figure is a circular shape in which a reflecting member is a semicircular cross section. The thing is shown. It is sectional drawing which shows the structure of the illuminating device of another Example which concerns on this invention.

1: Lighting device, 2: Frame body, 3: Display panel, 4: Light source device, 5: Transmission diffusion film, 6: Point light source, 7: Substrate, 8: Reflective hood, 9: Spacer, 10: Light diffusion sheet, 11: Screw, 12: Bottom part, 13: Side curved part, 14: Reflecting surface, 15: Mounting member, 16: Film, 17: Reflecting dot, 18: Reflecting film, 19: Opening part, 21: Film, 22: Reflective dot, 23: through hole, 24: nut, 25: screw hole, 26: through hole, 27: reflective member, 28: through hole

Claims (11)

A point light source,
A bottom portion on which the point light source is provided; and a pair of opposed side curved portions that extend outward from opposite sides of the bottom portion and whose ends are open, and the bottom portion and the pair of the side portions A reflective hood in which the surface facing the internal space surrounded by the curved portion is formed of a reflective surface;
A light diffusing sheet is provided at a position facing the point light source so as to close the opening of the reflective hood formed by the open ends of the pair of side curved portions. , Light source device. The light source device according to claim 1, wherein a spacer is provided between the bottom portion and the light diffusion sheet to maintain a distance between them. The light source device according to claim 1, wherein the reflective hood is formed of a reflective material that has high reflectivity and reflects irregularly. The light source device according to claim 3, wherein the reflective hood is made of an ultrafine foam reflective material. A substrate having a point light source is attached to the back of the channel of a substantially channel-type attachment member attached to the illumination device, and a light diffusion sheet is attached in the vicinity of the opening of the channel so as to close the opening. A light source device. The light source device according to claim 1, wherein the light diffusion sheet is provided with a plurality of through holes at a substantially central portion in the width direction with a space therebetween. The light source device according to claim 1, wherein the light diffusing sheet is provided with a slit along a longitudinal direction of the light diffusing sheet at a substantially central portion in a width direction. The light source device according to claim 1, wherein the point light source is one or a plurality of light emitting diodes or laser diodes. The two rectangular first and second light diffusing members are arranged to face each other with a predetermined gap, and the gap between at least one side of the first and second light diffusing members is defined in claim 1. A light source device according to any one of 8 to 8 is provided. A rectangular light diffusing member and a reflective film having a high reflectance are arranged to face each other with a predetermined gap, and at least one end side gap of the light diffusing member and the reflecting member is disposed in any one of claims 1 to 8. A light source device according to claim 1 is provided. The light diffusing member has a light reflectance higher on the side closer to the point light source and decreases as the distance from the point light source decreases, and a light transmittance is lower on the side closer to the point light source and increases as the distance from the point light source increases. The lighting device according to claim 9 or 10, characterized in that: