The present application is based on, and claims priority from JP Application Serial Number 2019-171301, filed Sep. 20, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a light source device and a projector.

2. Related Art

As a light source device used in a projector, there is proposed a light source device which is provided with a light emitting element such as a semiconductor laser, and uses fluorescence emitted from a phosphor when irradiating the phosphor with excitation light emitted from the light emitting element.

In JP-A-2017-62294 (Document 1), there is disclosed a light source device provided with a first light split element for splitting the light emitted from a first light emitting section into a first pencil of light and a second pencil of light, a second light split element for splitting the light emitted from a second light emitting section into a third pencil of light and a fourth pencil of light, a phosphor layer which the first pencil of light and the third pencil of light enter, and a rotary diffuser plate which the second pencil of light and the fourth pencil of light enter. In the rotary diffuser plate described above, a first diffused light emitting section which the second pencil of light enters and a second diffused light emitting section which the fourth pencil of light enters are disposed at respective positions different in distance from the rotational axis from each other.

In JP-A-2015-49441 (Document 2), there is disclosed an illumination device provided with a light source device, a phosphor layer of a reflective type for emitting fluorescence due to light from the light source device, a polarization split element for reflecting a part of the light from the light source device, transmitting the rest, and at the same time, transmitting the fluorescence, and a diffusely reflecting element for diffusely reflecting the light transmitted through the polarization split element. The diffusely reflecting element described above is formed of a diffusion element not provided with a motor for driving a diffuser plate, namely a so-called stationary diffusion element.

In the rotary diffuser plate described in Document 1, there is a problem that accessory components such as a driving motor, a power supply, and a control circuit become necessary besides the diffuser plate, and thus, the cost and the size of the light source device increase. This problem can be solved by using the stationary diffusion element described in Document 2. However, as the light source device increases in luminance, the density of the light with which the diffusion element is irradiated locally increases, and thus, the load on the diffusion element increases. As a result, there is a possibility that the reliability of the diffusion element degrades, and in some cases, the diffusion element is damaged.

SUMMARY

A light source device according to an aspect of the present disclosure includes a plurality of light emitting elements, a diffusion element which light beams including a plurality of beams emitted from the plurality of light emitting elements enter, and which diffuses the light beams, and an optical element configured to divide the light beams emitted from the plurality of light emitting elements into a plurality of partial light beams, wherein the diffusion element has a plurality of diffusion areas disposed so as to correspond to the plurality of partial light beams obtained by the optical element dividing the light beams emitted from the plurality of light emitting elements.

In the light source device according to the aspect of the present disclosure, a number of the diffusion areas may be no larger than a number of the light emitting elements.

In the light source device according to the aspect of the present disclosure, the optical element may include a plurality of first lenses disposed so as to correspond to the plurality of diffusion areas.

In the light source device according to the aspect of the present disclosure, outer circumferences having an effective diameter of the first lenses may be partially contiguous with each other.

In the light source device according to the aspect of the present disclosure, the optical element may be formed of a lens array having the plurality of first lenses integrated with each other.

The light source device according to the aspect of the present disclosure may further include a second lens configured to collimate the beams emitted from the plurality of light emitting elements, wherein the effective diameter of the first lens may be no smaller than an effective diameter of the second lens.

The light source device according to the aspect of the present disclosure may further include a polarization split element disposed between the plurality of light emitting elements and the optical element, wherein the polarization split element may split the light beams emitted from the plurality of light emitting elements into a first polarization component and a second polarization component different from the first polarization component.

The light source device according to the aspect of the present disclosure may further include a wavelength conversion element configured to perform wavelength conversion of the beams emitted from the plurality of light emitting elements, wherein the first polarization component may enter the diffusion element, and the second polarization component may enter the wavelength conversion element.

A projector according to another aspect of the present disclosure includes the light source device according to the aspect of the present disclosure, a light modulation device configured to modulate light from the light source device in accordance with image information, and a projection optical device configured to project the light modulated by the light modulation device.

