Projector with reduced speckle contrast

A projector includes a light source module, a diffuser for diffusing the light beam emitting from the light source module, and a fluorescent plate. The light source module includes a light source capable of emitting a first light beam, a dichroic device for diverging the first light beam into a second light beam and a third light beam, and a reflector with a moving frequency exceeding 20 Hz configured for reflecting the third light beam. The fluorescent plate is configured for converting the light beam passing through the diffuser into at least three kinds colored light beams.

BACKGROUND

1. Technical Field

The present disclosure relates to projectors and, particularly, to a projector with reduced speckle contrast.

2. Description of Related Art

In laser projectors, speckles of an image occur due to the interference of the light emitting from laser light sources. The speckles can mask part or all image display area, negatively affecting the users' viewing experience. Speckles may cause uncomfortable viewing experience for viewers.

What is needed, therefore, is a projector which can overcome or alleviate the above-described problem.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure will now be described in detail below, with reference to the accompanying drawings.

Referring toFIG. 1, a projector10, according to a first exemplary embodiment, is shown. The projector10includes a light source module100, a diffuser200, a fluorescent plate300, a light tunnel400, an illumination system500, a first driver600, and a second driver700. The diffuser200, the fluorescent plate300, the light tunnel400, and the illumination system500are arranged along the light path of the light beam emitting from the light source module100in sequence.

The light source module100includes a light source110, a dichroic device120, and a reflector130. The light source110is a laser light source, such as a laser diode. The dichroic device120is positioned in the light path of a first light beam L emitting from the light source110to diverge the first light beam L into a second light beam L1and a third light beam L2. The intensity ratio of the second light beam L1to the third light beam L2can be preset depending on requirements. The second light beam L1is directed to transmit towards the diffuser200along a first direction, and the third light beam L2is directed to transmit along a second direction, which can be substantially perpendicular to the first direction. The reflector130is arranged to reflect the third light beam L2to the diffuser200.

The first driver600includes a first driving rod610. The first driving rod610is fixed to the reflector130, to drive the reflector130to rotate. The reflector130can be swayed by the first driver600within a range of a predetermined angle θ1, such as 5°, with frequency exceeding 20 Hertz (Hz).

The diffuser200is configured for diffusing the second light beam L1and the third light beam L2emitting from the light source module100. In this embodiment, the diffuser200is a matte glass.

Further referring toFIG. 2, in this embodiment, the fluorescent plate300is disk-shaped, and includes three sectors covered with three kinds of fluorescent powder. It is understood that, in other embodiment, the number of the sectors of the fluorescent plate300can also be four, five, six and so on. The light beam passing through the diffuser200, can be converted into three different colored light beams, such as red, green and blue, by the three sectors of the fluorescent plate300respectively. The three sectors of the fluorescent plate300are inserted into the light path of the light beam passing through the diffuser200in sequence. Because the red, green and blue light beams converted by the fluorescent plate300are usually diffused light, in some embodiments, the diffuser200can also be omitted.

The second driver700includes a second driving rod710. The fluorescent plate300is fixed on the second driving rod710at the center thereof. Such that, the fluorescent plate300can be rotated by the second driver700about a center axis of the fluorescent plate300.

The light tunnel400normalizes the intensity of the light beam emitted from the fluorescent plate300and converted by the fluorescent plate300to provide a light beam with uniform brightness.

The illumination system500can include a plurality of lenses, the illumination system500receives the light beam from the light tunnel400and projects the optical images to a screen (not shown).

The reflector130of the projector10is movable, such as swayed etc. in a range with a frequency exceeding 20 Hz, thus, speckle contrast from the second and third light beams L1, L2is moved more than 20 Hz and cannot be seen by humans. As a result, the speckle contrast is reduced. Furthermore, by using the fluorescent plate300in the projector10, the projector10can project a color image.

Referring toFIGS. 3 and 4, a projector10aaccording to a second embodiment is shown. Differing from the projector10of the first embodiment, the projector10aincludes a first linear driver800instead of the first driver600, a second linear driver900instead of the second driver700, and a fluorescent plate300ainstead of the fluorescent plate300. The first linear driver800is configured for vibrating the reflector130along the light path of the third light beam L2, and the second linear driver900is configured for vibrating the fluorescent plate300aalong a direction substantially perpendicular to the light path of the light beam passing through the diffuser200.

The swing of the reflector130can be designed to be small enough to make sure the light beam reflected by the reflector130can reach the diffuser200and the fluorescent plate300a. In the present embodiment, the swing of the reflector130is in a range from 0 mm to 1 mm. The fluorescent plate300ais rectangular with three sectors covered with three different kinds of fluorescent powder. The three sectors are arranged on the fluorescent plate300aalong the vibrating direction of the fluorescent plate300a, therefore, the three sectors can be inserted into the light path of the light beam passing through the diffuser200in sequence.

Referring toFIGS. 5 and 6, a projector10baccording to a third embodiment is shown. Differing from the projector10of the first embodiment, the projector10bincludes a third driver910instead of the second driver700, and a fluorescent plate300binstead of the fluorescent plate300. The fluorescent plate300bis sector-shaped, and can be swayed by the third driver910along an axis O. In this embodiment, the third driver910includes two electromagnets910a,910b. The fluorescent plate300includes two magnets310corresponding to the two electromagnets910a,910b. By changing the polarity of the electromagnets910a,910b, the fluorescent plate300can be swayed along the axis O.

While certain embodiments have been described and exemplified above, various other embodiments will be apparent to those skilled in the art from the foregoing disclosure. The present invention is not limited to the particular embodiments described and exemplified, and the embodiments are capable of considerable variation and modification without departure from the scope of the appended claims.