Lighting apparatus

1. A lighting apparatus, comprising:

a light source;

a reflector plate which reflects light;

a diffuser plate which is light transmissive and is disposed to face the reflector plate;

a plate-shaped frame including an opening through which light exiting through the diffuser plate passes;

a light-transmissive plate that covers the opening of the frame,

wherein:

the frame covers an outer periphery of the diffuser plate in a front view of the opening,

a gap between the diffuser plate and the reflector plate gradually decreases from one end side of the diffuser plate and the reflector plate to an other end side of the diffuser plate and the reflector plate,

the light source is disposed on the one end side to emit light toward the diffuser plate and the reflector plate,

the diffuser plate includes a surface which faces the opening and is covered by an antireflection film that prevents reflection of light, and

the light-transmissive plate includes a surface which faces the diffuser plate and is covered by an antireflection film that prevents reflection of light.

2. The lighting apparatus according to claim 1 ,

wherein the frame has an inner surface having a black color that suppresses reflection of light.

3. The lighting apparatus according to claim 1 ,

wherein the opening has an inner circumference surface having a black color that suppresses reflection of light.

4. A lighting apparatus comprising:

a light source;

a reflector plate which reflects light;

a diffuser plate which is light transmissive and is disposed to face the reflector plate; and

eaves disposed on the other end side of the diffuser plate and the reflector plate, on a light-exit side with respect to a surface of the diffuser plate through which light exits,

wherein:

a gap between the diffuser plate and the reflector plate gradually decreases from one end side of the diffuser plate and the reflector plate to another end side of the diffuser plate and the reflector plate,

the light source is disposed on the one end side to emit light toward the diffuser plate and the reflector plate, and

the eaves have a surface on a light source side, the surface having a black color that suppresses reflection of light.

5. The lighting apparatus according to claim 4 ,

wherein the light source emits light of different luminescent colors.

6. The lighting apparatus according to claim 5 ,

wherein the light source includes a white light source which emits white light and a blue light source which emits blue light.

7. The lighting apparatus according to claim 4 ,

wherein the light source further includes an orange light source which emits orange light.

8. The lighting apparatus according to claim 4 ,

wherein the reflector plate is disposed substantially parallel with an optical axis of the light source.

9. The lighting apparatus according to claim 4 ,

wherein the diffuser plate is flat, and is disposed at a predetermined angle to the reflector plate, and

the predetermined angle is in a range from 2 degrees or greater to 10 degrees or less.

10. The lighting apparatus according to claim 4 ,

wherein less than or equal to 50% of light reflected by the reflector plate is diffusely reflected.

11. The lighting apparatus according to claim 4 ,

wherein the reflector plate is a mirror which reflects incident light.

12. The lighting apparatus according to claim 4 ,

wherein the reflector plate has a wavelength-selective property of absorbing light having a wavelength in a range from 610 nm or greater to 750 nm or less, and reflecting light having a wavelength in a range from 435 nm or greater to 495 nm or less.

13. The lighting apparatus according to claim 4 ,

wherein the diffuser plate is a Rayleigh diffuser plate which causes Rayleigh scattering of incident light.