Patent Application
20140168611
1. Technical Field
The disclosure generally relates to projection devices and more particularly to a laser projection device.
2. Description of Related Art
Laser projection devices are more and more popular for its projected images having a lager color gamut, a higher brightness, an increased contrast and a better saturation.
A conventional laser projection device includes a red light emitting diode (LED) package, a green LED package, a blue LED package, a spectroscope arranged on light paths of the LED packages and a photoelectric conversion device. Light emitted from the LED packages directly radiates to the spectroscope and then is reflected by the spectroscope to mix. And then, the mixed light can be modulated into images on a screen by the photoelectric conversion device. However, light emitted from the LED packages directly radiating into the spectroscope easily results in a light interference, which may seriously affect the performance of the laser projection device.
What is needed, therefore, is an improved laser projection device which can overcome the above described shortcomings
Embodiments of laser projection device will now be described in detail below and with reference to the drawings.
Referring to
The substrate 10 is flat. The light source 20, the lens 30 and the spectroscope 40 are arranged on a top surface of the substrate 10 in series along a longitudinal direction of the substrate 10. A circuit (not shown) is arranged on the top surface of the substrate 10. In this embodiment, the substrate 10 is made of electrically insulating materials, such as silicone, epoxy.
The light source 20 includes a plurality of laser chips. The laser chips are mounted on the top surface of the substrate 10. The laser chips are spaced from each other, and they are electrically connected to the circuit on the top surface of the substrate 10. A brightness of the laser chips can be controlled by a current flow through the circuit. The light source 20 is used to emit laser beams with colors needed.
In this embodiment, the light source 20 includes a blue laser chip (B) 21, a red laser chip (R) 22 and a green laser chip (G) 23. Each laser chip 21, 22, 23 is a laser diode. The blue laser chip (B) 21, red laser chip (R) 22, and the green laser chip (G) 23 are spaced from each other and arranged in a line along a transverse direction of the substrate 10. Alternatively, the arranged direction and the arranged sequence of the laser chips 21, 22, 23 are not limited.
The lens 30 is spaced from the light source 20, and located on the light paths of the light source 20. The lens 30 is made of materials with a consistent refractive index. The lens 30 is used to refract laser beams emitted from the light source 20 convergently into the spectroscope 40.
The lens 30 includes a main body 31, a plurality of first light concentrating parts 33 and a plurality of second light concentrating parts 35. In the first embodiment, the first light concentrating parts 33 and the second light concentrating parts 35 are integrally formed on opposite sides of the main body 31 and symmetrical relative to a middle line (not shown) of the main body 31 and so that a pair of first and second light concentrating parts 33, 35 is in line with a corresponding laser chip 21 (22, 23).
The main body 31 is cuboid. A longitudinal direction of the main body 31 is parallel to the transverse direction of the substrate 10.
Each of the first light concentrating part 33 is hemispherical. The first light concentrating parts 33 are protruding from a surface of the main body 31 facing the light source 20, and spaced from each other. In this embodiment, the number of the first light concentrating parts 33 is three. Each of first light concentrating parts 33 is aligned with a corresponding laser chip 21 (22, 23) along a longitudinal direction of the substrate 10.
The first light concentrating part 33 is used to refract laser beams emitted from a laser chip 21 (22, 23) corresponding with the first light concentrating part 33. As such, an interference of the laser beams emitted from the blue laser chip 21, the red laser chip 22 and the green laser chip 23 is reduced. Preferably, the laser beams emitted from each of the laser chips 21, 22, 23 are refracted by the corresponding first light concentrating part 33 to form parallel laser beams. The first light concentrating parts 33 are not limited to the shown hemispherical shape, as long as the interference of the laser beams are reduced by the first light concentrating parts 33.
The second light concentrating parts 35 are protruding from an opposite surface of the main body 31 facing the spectroscope 40 and spaced from each other. Each second light concentrating part 35 has a same shape and a same size to the first light concentrating part 33. Each second light concentrating part 35 is corresponding with a first concentrating part 33 along a longitudinal direction of the substrate 10. In the first embodiment, the number of the second light concentrating parts 35 is three.
Each of the second light concentrating parts 35 is hemispherical. The second light concentrating parts 35 are used to concentrate parallel laser beams from the corresponding first light concentrating parts 33 on the spectroscope 40. Alternatively, both of the first light concentrating parts 33 and the second light concentrating parts 35 can be Fresnel lenses, respectively.
The spectroscope 40 includes three beam splitters 41, 43, 45 respectively facing the laser chips 21, 22, 23 to refract the laser beams emitted from the laser chips 21, 22, 23. The beam splitters 41, 43, 45 are aligned with, parallel to and spaced from each other. The beam splitters 41, 43, 45 are slantwise and top ends thereof oriented toward the light source 20. An angle is defined between each of the beam splitters 41, 43, 45 and a top end of the substrate 10. The angle is varied between 10° to 45°. The laser beams emitted from the laser chips 21, 22, 23 are refracted by the beam splitters 41, 43, 45 to be oriented toward the same direction and mixed together to obtain light of a predetermined color which usually is white.
The beam splitter 41 faces the green laser chip 23 and can reflect the green laser beams and laser beams whose wavelength is near the wavelength of green laser beams, but allows laser beams with other wavelength to pass through. The beam splitter 43 may reflect the red laser beams and laser beams whose wavelength is near the wavelength of red laser beams, but allows laser beams with other wavelength to pass through. The beam splitter 45 may reflect the blue laser beams and laser beams whose wavelength is near the wavelength of blue laser beams, but allows laser beams with other wavelength to pass through. In this embodiment, green laser beams and laser beams whose wavelength is near the wavelength of the green laser beams are emitted from the green laser chip 23; red laser beams and laser beams whose wavelength is near the wavelength of the red laser beams are emitted from the red laser chip 22; blue laser beams and laser beams whose wavelength is near the wavelength of the blue laser beams are emitted from the blue laser chip 21.
Referring to
Similarly, the concentrated red laser beams on the beam splitter 43 are reflected by the beam splitter 43 to pass through the beam splitter 41. And the concentrated green laser beams on the beam splitter 41 are reflected by the beam splitter 41 to mix with the reflected blue laser beams passing through the beam splitters 43, 41 sequentially and the reflected red laser beams passing through the beam splitter 41. The mixed laser beams can be modulated into images on a screen by a photoelectric conversion device (not shown).
Referring to
Firstly, according to the laser projection device 100 of this disclosure, the blue laser chip 21, the red laser chip 22 and the green laser chip 23 are directly mounted on the single substrate 10 instead of mounted on three substrates to be packaged as three individual laser LED packages; as such, a bulk of the projection laser device 100 and a cost of manufacturing the projection laser device 100 are reduced. Secondly, the lens 30 is located on light paths of the blue laser chip 21, the red laser chip 22 and the green laser chip 23. As such, the laser beams emitted from the laser chips 21, 22, 23 are refracted by the corresponding first light concentrating parts 33 of the lens 30 to become parallel laser beams, which may reduce an interference of the laser beams. The parallel laser beams concentrated on the spectroscope 40 by the corresponding second light concentrating parts 35 make a brightness of the laser beams concentrated on the spectroscope 40 increased, which also reduces a diffusion of the laser beams. Thirdly, according to the projection laser device 100 of this disclosure, for the blue laser chip 21, the red laser chip 22 and the green laser chip 23 being mounted on the substrate 10 together, only one lens 30 is enough to refract the laser beams emitted from the laser chips 21, 22, 23, which makes the bulk of the laser projection device 100 reduced.
It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 101147265 | Dec 2012 | TW | national |
