U.S. patent application number 14/048777 was filed with the patent office on 2014-01-30 for projection-type display and control thereof.
This patent application is currently assigned to Honeywood Technologies, LLC. Invention is credited to William J. Plut.
Application Number | 20140028986 14/048777 |
Document ID | / |
Family ID | 42200854 |
Filed Date | 2014-01-30 |
United States Patent
Application |
20140028986 |
Kind Code |
A1 |
Plut; William J. |
January 30, 2014 |
PROJECTION-TYPE DISPLAY AND CONTROL THEREOF
Abstract
A projection display device that includes a set of light source
units (e.g., lasers or LEDs) and a control mechanism that monitors
performance of each of the units, as well as external factors,
e.g., time, ambient temperature, etc. is provided. The control
mechanism may dynamically adjust each light source unit, for
example, to maximize longevity. In operation, an optical modulator
is configured to selectively transmit light produced by a subset of
the light source units according to video data included in a video
signal provided to the projection-type display device. A projection
lens system is configured to project light transmitted by the
optical modulator along a projection path. A sensor detects real
time readings related to the performance of the set of light source
units. In accordance with the readings, a control circuitry
dynamically controls the laser set to dynamically vary the
luminance of the set of light source units.
Inventors: |
Plut; William J.; (Los
Altos, CA) |
Assignee: |
Honeywood Technologies, LLC
Los altos
CA
|
Family ID: |
42200854 |
Appl. No.: |
14/048777 |
Filed: |
October 8, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12473704 |
May 28, 2009 |
8585213 |
|
|
14048777 |
|
|
|
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Current U.S.
Class: |
353/85 ;
353/121 |
Current CPC
Class: |
G03B 21/142 20130101;
H04N 9/3161 20130101; H04N 9/3194 20130101; H04N 9/3155
20130101 |
Class at
Publication: |
353/85 ;
353/121 |
International
Class: |
G03B 21/14 20060101
G03B021/14 |
Claims
1. A method, comprising: using an output of a luminance sensor,
detecting, by a device, a luminance of an image projected by the
device onto a receiving surface external to the device, wherein the
luminance sensor is positioned as a function of a difference
between a field of view of the luminance sensor and an area of the
receiving surface on which the image is projected; monitoring at
least one criterion associated with a light source, wherein the at
least one criterion is evaluated relative to the luminance of the
image on the receiving surface; and selectively adjusting at least
a portion of the light source based upon a comparison of the at
least one criterion to at least one value.
2. The method of claim 1, wherein the function minimizes the
difference.
3. The method of claim 1, wherein the luminance sensor is located
on an exterior surface of the device.
4. The method of claim 1, wherein the adjusting comprises toggling
the portion of the light source on or off based upon the comparison
of the at least one criterion to the at least one value.
5. The method of claim 1, further comprising: detecting an ambient
light in an environment external to the device, wherein the at
least one criterion is evaluated relative to the ambient light.
6. The method of claim 1, wherein the light source comprises a set
of lasers.
7. The method of claim 1, wherein the light source comprises a set
of light emitting diodes.
8. A computer-readable storage device comprising
computer-executable instructions that, in response to execution,
cause a device to perform operations, comprising: via an output of
a luminance sensor, detecting a luminance of an image projected by
the device onto a receiving surface external to the device, wherein
the luminance sensor is positioned as a function of a difference
between a field of view of the luminance sensor and an area of the
receiving surface on which the image is projected; monitoring at
least one criterion associated with a light source, wherein the
monitoring the at least one criterion includes evaluating the
luminance of the image projected on the receiving surface; and
selectively adjusting at least a portion of the light source based
on a result of comparing the at least one criterion to at least one
threshold.
9. The computer-readable storage device of claim 8, wherein the
function minimizes the difference.
10. The computer-readable storage device of claim 8, wherein the
luminance sensor is located on an exterior surface of the
device.
11. The computer-readable storage device of claim 8, wherein the
adjusting comprises toggling the portion of the light source on or
off based on the result of comparing the at least one criterion to
the at least one threshold.
12. The computer-readable storage device of claim 8, wherein the
operations further comprise: detecting an ambient light in an
environment external to the device, wherein the monitoring the at
least one criterion further includes evaluating the ambient
light.
13. The computer-readable storage device of claim 8, wherein the
light source comprises a set of lasers.
14. The computer-readable storage device of claim 8, wherein the
light source comprises a set of light emitting diodes.
15. A device, comprising: a luminance component configured to
determine a luminance detected by a luminance sensor of an image
projected by the device directed toward a receiving surface
external to the device, wherein the luminance sensor is positioned
as a function of a difference between a field of view of the
luminance sensor and an area of the receiving surface toward which
the image is projected; a detection component configured to monitor
at least one criterion associated with a light source, wherein the
at least criterion includes the luminance of the image projected on
the receiving surface; and a controller component configured to
selectively adjust at least a portion of the light source based
upon a comparison of the at least one criterion to at least one
threshold.
16. The system of claim 17, wherein the function minimizes the
difference.
17. The system of claim 17, wherein the luminance sensor is located
on an exterior surface of the device.
18. The system of claim 17, wherein the portion of the light source
is turned on or off based upon the comparison of the at least one
criterion to the at least one threshold.
19. The system of claim 17, further comprising: an ambient light
sensor configured to detect an ambient light in an environment
external to the device, wherein the at least one criterion further
includes the ambient light.
20. The system of claim 17, wherein the light source comprises at
least one of a set of lasers or a set of light emitting diodes.
Description
CROSS-REFERENCE TO A RELATED APPLICATION
[0001] This application is a continuation of and claims priority to
U.S. application Ser. No. 12/473,704, filed May 28, 2009, and
entitled "PROJECTION-TYPE DISPLAY AND CONTROL THEREOF," the
entirety of which is incorporated herein by reference.
BACKGROUND
[0002] In general, a projection-type display or video projector
displays an image that corresponds to a video signal upon a
projection screen or other surface. Most modern devices are capable
of correcting distortion, curves, focus, and other inconsistencies
by way of manual controls. Traditionally, these video projection
devices are widely used for business presentations, classroom
training, home theater, etc. For example, projection devices are
widely used in many schools and institutions to project onto an
interactive white board during the course of teaching students.
[0003] Although projection-type display devices were initially
developed to display presentations (e.g., business, education),
today, these projection devices have become commonplace for home
theaters. For example, many households today include home theaters
specifically designed to view motion pictures upon a projection
screen. These theaters are often equipped with a projection-type
display device. Even though the cost of the devices has decreased
to an affordable level, at least one difficulty remains with regard
to consumer acceptance of the projection display device. This one
reservation is that the projection bulbs typically used in
projector are expensive lamps that have huge power consumption and
a generally short life span. Thus, while the cost of the machine is
affordable, maintenance is sometimes too expensive for many
families to justify or afford.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 illustrates an example block diagram of a system that
facilitates dynamic adjustment of a light source of a
projection-type display device.
[0005] FIG. 2 illustrates an example block diagram of a detection
component in accordance with aspects of the innovation.
[0006] FIG. 3 illustrates an example block diagram of a controller
component in accordance with aspects of the innovation.
[0007] FIG. 4 illustrates an example flow chart of procedures that
facilitate dynamic adjustment of a light source in accordance with
aspects of the innovation.
[0008] FIG. 5 illustrates an example schematic of projection-type
display device in accordance with aspects of the innovation.
[0009] FIG. 6 illustrates an example circuitry for use in a laser
set in accordance with aspects of the innovation.
[0010] FIG. 7 illustrates an example DPSS laser in accordance with
aspects of the innovation.
[0011] FIG. 8 illustrates an example multi-laser circuit board in
accordance with aspects of the innovation.
[0012] FIG. 9 illustrates an example block diagram of a
projection-type display device projecting images in accordance with
aspects of the innovation.
[0013] FIG. 10 illustrates an alternative example block diagram of
a projection-type display device projecting images in accordance
with aspects of the innovation.
[0014] FIG. 11 illustrates an alternative example block diagram of
a projection-type display device projecting images in accordance
with aspects of the innovation.
DETAILED DESCRIPTION
[0015] The following terms are used throughout the description, the
definitions of which are provided herein to assist in understanding
various aspects of the subject innovation.
[0016] The innovation is now described with reference to the
drawings, wherein like reference numerals are used to refer to like
elements throughout. In the following description, for purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of the subject innovation. It may
be evident, however, that the innovation may be practiced without
these specific details. In other instances, well-known structures
and devices are shown in block diagram form in order to facilitate
describing the innovation.
[0017] As used in this application, the terms "component," "module"
and "system" are intended to refer to a computer-related entity,
either hardware, a combination of hardware and software, software,
or software in execution. For example, a component may be, but is
not limited to being, a process running on a processor, a
processor, an object, an executable, a thread of execution, a
program, and/or a computer. By way of illustration, both an
application running on a server and the server may be a component.
One or more components may reside within a process and/or thread of
execution, and a component may be localized on one computer and/or
distributed between two or more computers.
[0018] The innovation disclosed and claimed herein, in one aspect
thereof, comprises a projection-type display device capable of real
time (or near real time) dynamic adjustment. A light source
management system may be employed that monitors criteria associated
to the light source of the display device. In accordance with
captured criteria, a controller component or circuitry may
dynamically adjust a subset of the light source.
[0019] In embodiments of the subject innovation, a detection
component (e.g., sensor) may monitor an image projected by a light
source. Luminance of the light source may be compared to a
threshold in order to determine if adjustment is appropriate. For
instance, if the luminance exceeds a threshold, the light source
may be reduced in power. Similarly, if the luminance is below a
predetermined threshold, the power may be increased
accordingly.
[0020] In yet other embodiments of the subject innovation,
temperature of each of the components of a light source may be
monitored. Similar to the above example, the temperature criteria
may be compared to a threshold. Here, if the temperature exceeds a
threshold, the individual light source component may be toggled or
switched off. Similarly, an individual light source may be toggled
or switched on as a function of temperature.
[0021] In accordance with the innovation, performance criteria
(e.g., luminance, temperature) may be captured in real time (or
near real time) enabling dynamic adjustment of the projection light
source. It will be understood that this dynamic adjustment may
increase longevity of the light source thereby decreasing operating
costs associated with a projection-type display device.
[0022] Referring initially to the drawings, FIG. 1 illustrates a
system 100 that facilitates dynamic adjustment of a light source in
accordance with aspects of the innovation. As shown, the system 100
may include a light source management system 102 that is capable of
monitoring and automatically adjusting a light source 104. For
example, based upon the temperature of each laser in a set of red,
green and blue lasers, the light source management system 102 may
dynamically, e.g., in real time or near real time, adjust luminance
of a subset of the lasers in a light source. Alternatively, the
light source management system 102 can dynamically adjust one or
more light emitting diodes (LEDs) of a set of LEDs based upon one
or more parameters being monitored. In this regard, any of the
embodiments described herein in the context of lasers, or diode
lasers, can also be applied to LEDs, or vice versa. Moreover,
embodiments presented in the context of lasers or LEDs are equally
applicable to monitoring and adjusting a combination of lasers and
LEDs as the light source 104. It is noted, however, that parameters
such as temperature drift and longevity tend to be more of an issue
for lasers than for LEDs. Accordingly, selected parameters can be
changed according to whether LEDs and/or lasers are involved in any
given embodiment. Additionally, based upon laser performance
criteria gathered, the light source management component 102 may
toggle lasers or LEDs on or off as appropriate so as to enhance
life or longevity of the laser devices.
[0023] Generally, light source management component 102 may include
a detection component 106 and a controller component 108. Together,
these components (106, 108) are capable of establishing
characteristics related to each of the lasers and comprehensively
making adjustments to the set of lasers employed within the light
source 104. The features, functions and benefits of the light
source management system 102 as well as its sub-components (106,
108) will be described in greater detail infra.
[0024] FIG. 2 illustrates an example detection component 106 in
accordance with aspects of the innovation. Generally, the detection
component 106 may include 1 to N sensor components 202, where N is
an integer. By way of example, the sensor component 202 may detect
luminance of each of the lasers in real time as an image is
projected. In accordance therewith, the controller component 108
may switch lasers on or off as deemed appropriate based upon the
luminance.
[0025] In other aspects, the sensor component 202 may monitor
temperature of each of the lasers (or LEDs). It will be appreciated
that longevity of the lasers (or light sources) may be affected by
extended use at high temperatures. Thus, in accordance with the
temperature reading established, the controller component 108 may
switch appropriate light sources on or off to avoid or minimize
extended use of individual lasers at high temperatures so as to
enhance longevity and performance of the sources within the
projection-type device.
[0026] In yet another aspect, the sensor component 202 may monitor
ambient light with the environment of a projected image. Here, as
appropriate, luminance may be increased or decreased in each of the
lasers of the light source 104 so as to optimize or otherwise
enhance performance. Similarly, lasers may be toggled on or off as
appropriate.
[0027] Turning now to FIG. 3, a block diagram of an example
controller component 108 is shown in accordance with aspects of the
innovation. Generally, the controller component 108 (e.g., control
circuitry) may include an analysis component 302 and an adjustment
component 304. Together, these sub-components (302, 304) may
process real time (or near real time) readings from the detection
component 106 to ultimately manage operation of each of the lasers
(or LEDs) within a light source 104.
[0028] In operation, the analysis component 302 may evaluate the
information and criteria received from the detection component 106.
For instance, the information may be compared against a threshold
or limit. It is to be understood that the threshold or limit may be
based upon predefined criteria established by a user or
manufacturer. In other aspects, the threshold may dynamically shift
based upon environmental factors (e.g., ambient light, temperature)
as well as the scope of use.
[0029] The adjustment component 304 may be used to automatically
regulate use of each of the lasers. Similarly, the adjustment
component 304 may dynamically calibrate luminescence (or other
parameters) of each of the lasers, for example, to optimize visual
representation of an image. In addition to regulating or
calibrating luminance, the adjustment component 304 is also capable
of toggling all or a subset of the lasers on or off as appropriate.
It is to be understood and appreciated that "luminance" may refer
to a measure of the brightness of a surface, equal to the amount of
luminous flux arriving at, passing through, or leaving a unit area
of surface. Further, luminance is most often measured in candelas
per square meter.
[0030] FIG. 4 illustrates a methodology of dynamically controlling
lasers and/or LEDs within a projection device in accordance with
aspects of the innovation. While, for purposes of simplicity of
explanation, the one or more methodologies shown herein, e.g., in
the form of a flow chart, are shown and described as a series of
acts, it is to be understood and appreciated that the subject
innovation is not limited by the order of acts, as some acts may,
in accordance with the innovation, occur in a different order
and/or concurrently with other acts from that shown and described
herein. For example, those skilled in the art will understand and
appreciate that a methodology could alternatively be represented as
a series of interrelated states or events, such as in a state
diagram. Moreover, not all illustrated acts may be required to
implement a methodology in accordance with the innovation.
[0031] At 482, light is produced, for example, a set of lasers is
used to generate light. Criteria related to at least either, or
both, the image generated by the set of lasers or to each of the
lasers themselves, at 484. For example, luminance of the image is
captured. Video data may also be captured. In another example, the
temperature of each laser is captured. In still another aspect,
ambient light is measured. Light produced by a laser or set of
lasers (e.g., the red lasers in a set) may also be detected. Once
the criteria are collected, it is compared to a threshold at
486.
[0032] A determination is made to establish if the criteria exceeds
a threshold at 488. As stated above, the threshold may be
predefined or otherwise related to other parameters. For example,
the threshold of an acceptable laser temperature may be a function
of lifecycle testing for the laser. In other words, the laser may
have certain temperature thresholds above which failure is more
likely to occur, or temperature thresholds above which longevity
failures due to prolonged use at the elevated temperature are more
likely. If it is determined that the threshold is not exceeded by
the captured criteria, the methodology returns to 484 to monitor
real time criteria.
[0033] If, on the other hand, it is determined that the threshold
is exceeded, the lasers may be adjusted at 490. In other words, in
aspects, a subset of the lasers may be toggled on or off in
accordance with the comparison. It is to be understood that most
any adjustment of the lasers may be performed in response to the
captured criteria as appropriate or desired.
[0034] FIG. 5 illustrates an example block diagram of a
projection-type display device 10 in accordance with embodiments of
the innovation. Display device 10 is configured to produce and
project a video image for display upon a receiving surface. As
shown, display device 10 comprises light source 110, optical system
120, optical modulator 130, projection lens system 140, control
circuitry 150, luminance sensor 152, housing 20, fans 62, power
supply 66, input/output circuitry 74, and input/output interfaces
78. The light source 110 is capable of producing a desired amount
of light. In embodiments, the light source 110 is a set of lasers,
wherein each laser diode in the set may be individually switched
off or on.
[0035] In the example, the light source 110 uses a red laser set
12, a green laser set 14 and a blue laser set 16, one set for each
primary color, though, as mentioned, alternate embodiments can
substitute LEDs for lasers, and vice versa. The optical system 120
is arranged to receive light produced by the light source before
receipt by the optical modulator 130, and configured to increase
flux area of the light. The optical modulator 130 configured to
selectively transmit light produced by the set of lasers according
to video data included in a video signal provided to the
projection-type display device. Projection lens system 140
comprises prism structure and lens set. As described supra, the
luminance sensor 152 detects a real time (or near real time)
reading measuring an image projected by the projection-type display
device. In response thereto, the control circuitry 150 dynamically
controls the light source 110 based on the real time readings to
dynamically vary the luminance of a subset of the set of
lasers.
[0036] Housing 20 defines outer dimensions of the display device 10
and a chamber 65 within display device 10. Housing 20 also provides
mechanical protection for internal components of display device 10.
As shown, housing 20 comprises four walls 23a-23d, a top wall (not
shown), and a bottom wall (not shown). Walls define a chamber 65
within housing 20. Walls 23a-23d comprise a suitably stiff or rigid
material that grants structural rigidity for display device 10 and
mechanical protection for internal components within housing 20,
such as a metal or molded plastic. One or more walls 23a-d of
housing 20 may also include an air vent that permits airflow
between chamber 65 and an environment external to housing 50. Vents
may also be placed on the top and bottom walls of housing 20.
[0037] Power supply 66 provides electrical power to red laser set
12, green laser set 14, and blue laser set 16 and other components
within display device 10 that consume electrical power. Thus, power
supply 66 may provide electrical energy to control circuitry 150,
input/output circuitry 74, fans and optical modulator 130. A power
cord port 81 receives a power cord, which couples power supply 66
to an AC power source such as a wall power supply. In embodiments,
conversion of AC power to DC power occurs in a transformer included
between ends of the power cord thereby reducing the size of power
supply 66 and display device 10 and increasing the portability of
display device 10.
[0038] In other embodiments, power supply 66 comprises at least one
battery 66a. The battery 66a may be a rechargeable battery and be
recharged using power provided through power cord port 81. Battery
66a allows display device 10 to operate on stored energy and
without reliance on proximity to an AC power source, which further
increases portability of display device 10. For example, inclusion
of a battery in housing 20 extends display device 10 usage to
settings where AC and fixed power outlets are not available or
within reach.
[0039] Lasers as described herein, such as those included in red
laser set 12, green laser set 14 and blue laser set 16, produce
laser light having a wavelength between about 400 nanometers and
about 700 nanometers, which is generally accepted as the visible
spectrum. It is to be understood that more or less lasers of the
same or different color may be employed in alternative aspects.
Laser light refers to light that is generated using a lasing
mechanism, which in some cases may be manipulated after initial
generation to achieve a desired frequency, as will be described in
further detail below. In the example, red laser set 12, green laser
set 14, and blue laser set 16 respectively produces red, green and
blue laser light to be used as light source of the display device
10. In some other embodiments, as mentioned, LEDs are also capable
of being adopted as the light source separate from or in
combination with lasers.
[0040] In embodiments, each laser emits substantially collimated
light. Collimated light differs from radiant light (e.g., from a
lamp or light emitting diode) and is characterized by light that
travels in about the same direction. Laser light emitted from each
laser may also be characterized as coherent. The coherency of laser
light relates to the constancy of the spatial and temporal
variations in the light or radiation wave fronts. A high degree of
coherence implies a substantially constant phase difference between
two points on a series of about equal amplitude wave fronts
(spatial coherence); and a correlation in time between the same
points on differently wave fronts (temporal coherence). If a laser
beam is considered as a plane wave traveling in one direction, it
is spatially coherent due to the perpendicularity of wave fronts in
the direction of propagation. Also, due to the roughly
monochromatic nature of laser light emitted from lasers as
described herein, the beam is generally temporally coherent, that
is, it will display an about fixed phase relation between a portion
of the beam emitted at one time and a portion emitted at
another.
[0041] Control circuitry 150 provides control signals to components
within display device 10, and may route data from input/output
circuitry 74 to appropriate components within display device 10.
Thus, lasers in red laser set 12, green laser set 14 and blue laser
set 16 receive control signals from control circuitry 150 that
regulates each laser when each laser is turned on/off. More
specifically, control circuitry 150 receives video data included in
a signal via one or more input/output interfaces 78 and
input/output circuitry 74, converts the video data to pixel data on
a sequential color frame basis, and delivers the sequential color
pixel data to the optical modulator 130 and to each diode laser. In
a combined light transmission path design between sets of lasers
and optical modulator 130 where light is transmitted along a common
light path that transmits red, green and blue light in a sequential
red, green and blue order, control circuitry 150 synchronizes the
timing of colored data sent to optical modulator 130 and on/off
commands sent to red laser set 12, green laser set 14 and blue
laser set 16 respectively.
[0042] Controller component or control circuitry 150 may also
include and access memory that stores instructions for the
operation of components within display device 10. For example,
stored heat regulation instructions may specify control signals
sent by control circuitry 150 to fans. As described above, one or
more temperature sensors may also be disposed within housing 20 to
facilitate thermal regulation. For example, a temperature sensor
may be disposed proximate to input/output circuitry 74 and control
circuitry 150 to monitor temperature levels and participate in
closed loop temperature control within display device 10 as
determined by stored logic implemented by control circuitry 150.
Alternately, temperature sensors arranged for each diode laser may
sense temperature levels for each laser and output information that
affects fan usage based on stored instructions for desired laser
temperature levels. Control circuitry 150 may comprise a
commercially available processor, controller or microprocessor such
as one of the Intel or Motorola family of chips, for example.
[0043] Input/output interfaces 78 are configured to receive at
least one cable, wire, or connector, such as a cable for
transmitting a video signal comprising video data from a digital
computing device. Common ports suitable for use with input/output
interfaces 78 may include ports that may receive S video cable,
6-pin mini DIN, VGA 15-pin HDDSUB, an audio cable, component RCA
through an S-Video adaptor, composite video RCA cabling, a
universal serial bus (USB) cable, fire wire, etc. Input/output
interfaces 78 may also include an audio output port for receiving a
wired connection from speakers included in a headphone or speaker
system.
[0044] Input/output circuitry 74 provides an interface between
control circuitry 150 and one or more interfaces from input/output
interfaces 78. Input/output circuitry 74 and input/output
interfaces 78 collectively permit communication between display
device 10 and a device that outputs a video signal carrying video
data. Video data provided to control circuitry 150 may be in a
digital or an analog form (e.g., from a VCR (video cassette
recorder). In some cases, input/output circuitry 74 and control
circuitry 150 convert analog video signals into digital video
signals suitable for digital control of an optical modulator 130
included in display device 10, such as a liquid crystal display
"LCD" device or a digital micro minor "DMD" device.
[0045] Input/output circuitry 74 or control circuitry 150 may also
include support software and stored logic for particular connector
types, such as processing logic required for S-video cabling or a
digital video signal. Control circuitry (or controller) 150
includes or accesses stored logic in memory to facilitate
conversion of incoming data types and enhances video compatibility
of display device 10. Suitable video formats having stored
conversion instructions within memory accessed by control circuitry
150 may include NTSC, PAL, SECAM, EDTV, and HDTV (1080i and 720p
RGBHV), for example.
[0046] Fans 62a and 62b move air through chamber 65 of housing 50
for cooling components of display device 10. In embodiments, fans
draw air in through inlet air vents 24a on one side of housing 20
and exhaust heated air out of air vents 24b after the air has
cooled internal components of projection-type display device 10 and
walls of housing 20. It is to be appreciated that fan and vent
placement will vary with internal component placement within
chamber 65 of light source. Specifically, fan placement, and
airflow patterns affected by fans within chamber 65, is designed
according to individual temperature regulation requirements and
heat generation contributions of components within housing 50.
[0047] Typically, red laser set 12, green laser set 14 and blue
laser set 16 and power supply 66 generate the largest proportion of
heat within housing 20. Correspondingly, inlet air 69 passes
through inlet air vents 24a, initially passes and cools optical
modulator 130, control circuitry 150 and input/output circuitry 74
while the air is relatively cool, passes across power supply 66 and
red laser set 12, green laser set 14 and blue laser set 16, and
exits out exhaust air vents 24b. The exhaust air may also cool fan
motors 63a and 63b, which rotate fans 62a and 62b, respectively. In
embodiments, multiple fans are used to permit a lower profile for
housing 20. As one skilled in the art will appreciate, the number
and size of fans used will depend on heat generation within display
device 10 and a desired airflow to maintain one or more heat
dissipation goals. Chamber 65 may also include one or more airflow
guides 67 those are vertical or horizontal within chamber 65 to
direct and distribute airflow as desired. In embodiments, circuit
boards 430 for red laser set 12, green laser set 14 and blue laser
set 16 are vertically arranged perpendicular to the direction of
airflow within chamber 65 and airflow guides 67 are arranged to
direct cooling air across the surfaces of each circuit board
430.
[0048] In embodiments, light output can be from LEDs or lasers. For
instance, with lasers, light output from the lasers in red laser
set 12, green laser set 14 and blue laser set 16 is provided to
fiber optic cabling 72. Fiber optic cabling 72 includes one or more
fiber optic cables configured to transmit light from lasers in red
laser set 12, green laser set 14 and blue laser set 16 along
multiple or common optical paths to relay optics 80, which is
disposed along a light path between an exit end of fiber optic
cabling 72 and an optical modulator 130. Each fiber optic cable
comprises an inlet end 72a configured to receive light from a laser
in one of the laser sets and an outlet end 72b configured to outlet
the laser light for transmission to relay optics, and subsequent
transmission to optical modulator 130. Since fiber optic cabling 72
may be bent and flexibly positioned, fiber optic cabling 72
advantageously permits light transmission between lasers sets and
relay optics regardless of the positioning and orientation between
the laser sets and relay optics. For example, this allows flexible
arrangement of lasers in different laser sets relay optics and
prism structure, which may be used to improve space conservation
within housing 20, decrease the footprint of housing 20, and
minimize display device 10 size.
[0049] The number of fiber optic cables may vary with design.
Multiple fiber optic cables may be employed in a design where each
cable services one or more lasers. Multiple fiber optic cables may
be employed in a design where each cable is configured to transmit
a primary color. For example, three fiber optic cables may be
employed in which each cable transmits light from a primary color
set along three different optical paths to three primary color
dedicated optical modulators. Alternately, as shown in FIG. 5, a
common fiber optic cable may be used to transmit sequentially
emitted red, green and blue light along a common light path to a
single mirror-based optical modulator 130. Fiber optic cabling 72
may comprise single mode or multimode fibers such as those readily
available from a wide variety of vendors known to those skilled in
the art. In some cases, a converging lens is disposed at outlet end
72b when fiber optic cabling 72 is a single mode fiber to correct
for most any divergence resulting from light transmission within
the single mode fiber optic cabling 72.
[0050] Fiber optic interface 70 is configured to facilitate
transmission of light from each laser into fiber optic cabling 72.
Fiber optic interface 70 may include one or more fixtures that
position and hold an inlet end for each fiber optic cable included
in fiber optic cabling 72 such that light output from each laser
transmits into a fiber optic cable. Fiber optic interface 70 may
also include optics that direct light from the lasers into fiber
optic cabling 72. In embodiments, a single fiber optic cable used
in fiber optic cabling 72 and fiber optic interface 70 includes a
lens system disposed between the outlet of each laser and the inlet
of the single fiber optic cable to direct light from each laser
into the single cable. The lens system may comprise at least two
lenses: a first lens to direct the light towards the fiber entrance
and a second lens that re-collimates light entering the cable.
[0051] In other embodiments that implement a one-to-one laser to
fiber optic cable 72 relationship, fiber optic interface 70 holds
the inlet end 72a for each fiber optic cabling 72 relatively close
to the outlet of a single laser to receive light therefrom. Each
cable in this case may include a converging lens at its inlet end
that facilitates light capture and transmission into the fiber
optic cable. In one-to-one embodiments, each fiber optic cable in
fiber optic cabling 72 includes a fixture that permits attachment
to a laser. For example, conventionally available fiber optic
cables available from vendors such as Ocean Optics Inc. of Dunedin,
FL include a detachable fixture with a thread that allows screwing
and fixing of the fiber optic cable to a mating thread disposed on
a laser housing. In this case, fiber optic interface 70 comprises
the threaded fixture for each fiber optic cable and a mating thread
is added to the laser housing.
[0052] In common light path transmission embodiments, light from
lasers in each laser set travels along a common path before receipt
by optical modulator 130. In this case, red, green and blue light
is provided to fiber optic cabling 72 in a time synchronous manner
that corresponds to red, green and blue video data provided in a
video signal to optical modulator 130.
[0053] Relay optics 80 converts light received from fiber optic
cabling 72 to light flux suitable for transmission onto optical
modulator 130 via prism structure. This may include shaping and
resizing light flux received from fiber optic cabling 72 using one
or more lenses, and may include homogenizing intensity across the
light flux distribution. To do so, relay optics may comprise one or
more lenses suitably spaced and arranged within housing 20. In
embodiments, first lens 80a is selected and arranged to increase
the area of light flux received from fiber optic cabling 72, while
second lens 80b is selected and arranged to convert the divergent
light transmitted by first lens 80a into substantially collimated
flux for transmission onto optical modulator 130.
[0054] A rotating diffuser 82 is disposed between first lens 80a
and second lens 80b. Rotating diffuser 82 comprises a transparent
glass screen 84 that is rotated by a motor 86. As shown in FIG. 5,
rotating diffuser 82 intercepts an unfocused beam, thereby reducing
both temporal and spatial coherence, and reducing potential speckle
in the output image. In other embodiments, rotating diffuser 82 is
introduced into the light path between the exit the fiber optic
cabling 72 and before receipt by lens 80a.
[0055] One skilled in the art will appreciate that rotating
diffuser 82 may be arranged in other locations along the light path
between generation of laser light in laser sets and output of the
projected image from external projection lens 140h. For example,
rotating diffuser 82 may be arranged proximate to a junction where
light from multiple fiber optic cables is transmitted into a common
fiber optic cable. In this case, rotating diffuser 82 may be
arranged at the focus of a beam to only reduce temporal coherence,
while maintaining the spatial coherence (e.g., the ability for the
beam to be focused to a point).
[0056] Rotating diffuser 82 may also be arranged to intercept light
between a laser and a fiber optic coupling, or between a final
relay lens and prism structure, for example. In embodiments, the
coherence diffuser is arranged to intercept laser light before it
is expanded in flux area by any relay optics. Intercepting a small
flux area light beam reduces the size of the transparent glass
screen 84 and coherence diffuser motor 86.
[0057] In embodiments, relay optics comprise a pair of fly-eye
lenses arranged in the optical path between laser sets and prism
structure, such as between second lens 80b and prism structure.
Cumulatively, the pair of fly-eye lenses re-distributes light
uniformly across the flux transmitted onto optical modulator 130.
The first fly-eye lens includes a plurality of lenses that
spatially divide input light flux (e.g., from second lens 80b) into
a set of blocks or components that each comprise a portion of the
total inlet flux area, and transmits light for each block to a
corresponding block in the second fly-eye lens. The second fly-eye
lens includes a plurality of lenses, the number of which is the
same as the number of lenses in the first fly-eye lens, and outputs
light for each component to an object region to be illuminated in
such a manner that the partial luminance fluxes from each lens are
superimposed on each other at the object region.
[0058] In other embodiments, relay optics comprise an integrator
tunnel disposed in the optical path between lasers sets and prism
structure, such as between lens 80b and prism structure. The
integrator tunnel uses total internal reflection to output luminous
flux with an about uniformly distributed intensity across a shape
determined by an output geometry at output end, which is typically
rectangular. The outlet may also be dimensioned to match the aspect
ratio of the downstream optical modulator 130. The integrator may
comprise a solid glass rod such as those known and used in the art.
If required, one or more lenses may be arranged to re-size flux
output by the integrator tunnel from a size that exists at an
output end to a size that is suitable for reception by optical
modulator 130.
[0059] Prism structure provides light to optical modulator 130 at
predetermined angles, and transmits light from optical modulator
130 to the projection lens set along output path 31. Prism
structure comprises prism components 140a and 140b that are
separated by air space or bonding interface 140c. Bonding interface
140c is disposed at such an angle so as to reflect light provided
from relay optics towards optical modulator 130. In addition,
bonding interface 140c allows light reflected by optical modulator
130 to transmit to projection lens set along output path 31.
[0060] Optical modulator 130 selectively transmits (or reflects)
light to provide an output image along output path 31. To do so,
optical modulator 130 is supplied with video data included in a
video signal and selectively transmits light according to the video
data. The video data is typically provided to optical modulator 130
on a frame-by-frame basis according to individual pixel values. If
the video data is not received by projection-type display device 10
in this format, control circuitry 150 in housing 20 converts the
video data to a suitable format for operation of optical modulator
130. In embodiments, individual light modulation elements within
optical modulator 130, which each correspond to an individual pixel
on the output image, translate received digitized pixel values into
corresponding light output for each pixel.
[0061] In embodiments, optical modulator 130 is a minor based
spatial light modulator, such as a digital micro-minor device (or
DMD, a trademark of Texas instruments Inc.) commercially available
from Texas Instruments, Inc. Most any XGA or SVGA resolution chip
in the SDR or DDR series is suitable for use with embodiments. In
this case, optical modulator 130 comprises a rectangular array of
tiny aluminum micromechanical mirrors, each of which individually
deflects about a hinged axis to selectively reflect output image
light down output path 31, and reflect non-image light away from
output path 31. The deflection state or angle of each mirror is
individually controlled by changing memory contents of an
underlying addressing circuit and minor reset signal. The array of
mirrors is arranged such that each mirror is responsible for light
output of a single pixel in the video image. Control signals
corresponding to pixel output are supplied to control electrodes
disposed in the vicinity of each mirror, thereby selectively
deflecting individual minors by electromagnetic force according to
video data on a pixel by pixel basis. Light reflected by each minor
is then transmitted along output path 31, through prism structure
140a-140e, and out of projection-type display device 10 using
projection lens set.
[0062] The arrangement of relay optics 80 and the faces of prism
structure control the illumination angles for optical modulator
130. After light reflection by individual minors of optical
modulator 130, reflected light exits prism structure towards
projection lens set along output path 31. Output path 31
characterizes a) the direction of image light selectively
transmitted by optical modulator 130 within display device 10, and
b) the direction of light output from display device 10. For light
selectively transmitted by optical modulator 130, output path 31
extends as a straight line from optical modulator 130 for elements
in their `on` state, through prism structure 140a-140e, and out
external projection lens 140h.
[0063] A projection lens set is disposed along output path 31
configured to project light transmitted by the optical modulator
along output path 31 from display device 10. Projection lens set
manipulates image light transmitted by optical modulator 130 along
output path 31 such that a projected image cast on a receiving
surface enlarges as distance from projection lens 140h to the
receiving surface increases. Projection lens set comprises first
projection lens 140f, second projection lens 140g and external
projection lens 140h, each of which is disposed centrically along
and orthogonal to output path 31. Distances between each projection
lens may vary with a desired splay angle from external projection
lens 140h, as may the number of projection lens set used. In
embodiments, display device 10 is designed for a short throw
distance, such as between about six inches and about 15 feet.
Display device 10 may also include one or more buttons or tools
that allow a user to manually focus and manually zoom output from
projection lens set.
[0064] In operation, light generated by lasers in laser sets is
collected by and transmitted within fiber optic cabling 72. Relay
optics 80 convert light transmitted by fiber optic cabling 72 to a
luminous flux size suitable for transmission onto optical modulator
130 via reflection within prism structure 140a-140e. Light
propagating through prism component 140a reflects off a surface
140d at bonding interface 140c by total internal reflection and
forms a reflected pre-modulated beam directed towards optical
modulator 130. The reflected pre-modulated beam travels through
prism component 140a to reach optical modulator 130, which
selectively transmits light according to video data in a signal
that corresponds to an image to be projected. Light output through
exit face 140e is characterized by output path 31, which propagates
through projection lens set that manipulates image light for
enlarged display onto a screen or suitable receiving surface.
Typically, the image is cast with a splay angle such that the image
enlarges as the distance to a receiving surface increase.
[0065] In embodiments, the luminance sensor 152 may be photodiode
arrays, charge-coupled device (CCD) camera or complementary metal
oxide semiconductor (CMOS) camera. However, any other light sensor
or camera with the desired light sensitivity may be used as a
luminance sensor for the purposes of the light intensity detection.
The luminance sensor 152 may be incorporated with, connected to, or
otherwise associated with the projector a) to detect light directly
emitted from one or more lasers, b) within the projector to detect
light at some point between laser generation and before output from
the projections optics, and/or c) to detect light at a cast image.
In embodiments, the luminance sensor 152 may be mounted on the
receiving surface. Alternatively, the luminance sensor 152 may be
attached to the projection-type display device 10, such as by
either mounting the luminance sensor 152 on the exterior of the
projection-type display device, or by incorporating the luminance
sensor 152 within the projection-type display device itself. In
either scenario, the luminance sensor 152 may be located so as to
minimize differences in the field of view of the sensor and the
area of the projected image.
[0066] In embodiments, the control circuitry 150 updates the
desired amount of light based on the real time readings, and
selectively turns off a subset of lasers when the real time
readings is lower than a predetermined threshold. Alternatively,
the control circuitry updates the desired amount of light based on
the real time readings, and selectively turns on the subset of the
lasers when the real time reading exceeds a predetermined
threshold. The real time reading may relate to video data being
projected, condition of one or more lasers (e.g., temperature or
duration of light projection), or combinations thereof. For
example, when a screen goes black in a movie, the luminance sensor
152 may detect that the luminance of projected image become lower.
The control circuitry 150 updates the desired amount of light, so
that the light source 110 may adjust the output power of the light
source 110.
[0067] In other embodiments, the total number of lasers in the set
of lasers (or LEDs) is greater than a number of lasers needed to
produce a desired amount of light at maximum luminance for an
image. This is referred to as `redundant` laser supply. For
example, a set of six lasers may only need five lasers to generate
and emit the desired amount of light. The sixth laser allows
failure of one laser in the set to not compromise operability of
the entire set--and the display device.
[0068] In addition to having an extra laser, the extra laser(s) in
a laser set also allow the lasers to be cycled for heat dissipation
purposes and to extend longevity of each and all lasers in the set.
More specifically, lasers in a red, green or blue laser set cycle
or other wise toggle on and off to reduce local heat generation for
each laser. This periodic redundant laser cycling keeps sum
temperatures lower for each laser and reduces local heat generation
at each laser--thereby extending longevity of each laser, its
corresponding laser set, and the device.
[0069] The amount of cycling and shut down duration for each laser
(for temperature and heat generation relief) will depend on the
number of extra redundant lasers included in a set, as one of skill
in the art will appreciate. As the number of lasers increases, the
shut down duration for each laser--in terms of frequency and time
spent off--will increase.
[0070] The amount of cycling and shut down duration may also depend
on the intensity of light needed. For example, the number of active
lasers being used can be reduced when the video to be displayed
needs less intensity (e.g., dark scenes).
[0071] Heat removal speeds and dynamics may also affect cycling
durations and times. If heat removal benefits from slightly
elevated temperatures, then cycling may be reduced to elevate
temperatures and drive faster heat dissipation.
[0072] A temperature sensor 154 that detects the temperature of the
set of laser is provided. The control circuitry 150 is configured
to determine the temperature of each laser in the set of lasers.
For example, the control circuitry turns off the laser diode with
the highest temperature among the set of lasers. In other
embodiments, a timer for measuring the time the set of lasers
exceeds a predetermined amount is included in projection-type
display device. The control circuitry 150 operates to turn off a
laser diode which has been ignited a predetermined period of
time.
[0073] It will be understood that temperature based redundant
control increases longevity for individual lasers that benefit from
periodic shutdown and those whose endurance suffers from elevated
heat exposure, thereby also increasing longevity for a display
device on a given redundant laser set.
[0074] In yet other embodiments, the projection-type display device
10 includes an ambient light sensor 156. The ambient light sensor
156 detects the luminance of ambient light of the projection
environment. Accordingly, the control circuitry 150 may increase
the desired amount of light if the luminance of ambient light
exceeds a predetermined level, and decreases the desire amount of
light if the luminance of ambient light is less than the
predetermined level.
[0075] FIG. 6 illustrates an example circuit for use in red laser
set 12 (or as adapted for LEDs in alternate embodiments). In
embodiments, each diode laser in red laser set 12 generates and
emits red light including a wavelength between about 615 and about
690 nanometers. Each diode laser in red laser set 12 may include a
lasing medium and laser cavity configured to generate and emit
light including a wavelength between about 625 and about 645
nanometers. As the term is used herein, a diode laser refers to a
device, system or module that outputs laser light and employs a
semiconductor to generate the laser light. Diode laser 400 is also
commonly referred to as a semiconductor laser, a laser diode or
injection laser. Diode laser 400 comprises lasing medium 402,
output lens 404, lasing chamber 408, monitor photodiode chip 412,
housing 414, leads 416, control circuitry 418, and correction lens
420, all mounted on circuit board 430.
[0076] In embodiments, each laser in green laser set 14 emits light
including a wavelength between about 510 and about 570 nanometers.
Green laser set 14 may comprise green laser light emitting diode
pumped solid state lasers that each emit green light including a
wavelength between about 530 nanometers and about 550 nanometers.
In embodiments, green laser set 14 and/or blue laser set 16
comprises one or more diode pumped solid-state (DPSS) lasers.
Solid-state lasers generally employ a crystal doped with an
impurity within their active lasing medium. A DPSS laser refers to
a device, system or module that outputs laser light.
[0077] FIG. 7 illustrates an example schematic of DPSS laser 450 in
accordance with embodiments. DPSS laser 450 comprises a pumping
light source 451, lasing medium 452, output optics 454, lasing
chamber 458, housing 464, control circuitry 468, and optics 470,
crystal 461, coupler mirror 457, and circuit board 430.
[0078] Blue laser set 16 is designed or configured to produce blue
light for use in display device 10. In embodiments, each laser in
blue laser set 16 emits blue light including a wavelength between
about 420 and about 500 nanometers. Blue laser set 16 may include
blue diode lasers and each blue diode laser comprises a lasing
medium and laser cavity for generating and emitting light including
a wavelength between about 430 and about 460 nanometers. Blue diode
lasers suitable for use in blue laser set 16 are described in
further detail with respect to FIG. 6. Blue laser set 16 may
include blue laser light emitting diode pumped solid-state lasers,
which are depicted in FIG. 7.
[0079] In general, the combined power of lasers for each color set
may be adapted according to a desired light intensity output for
display device 10 and according to the light sensitivity of a
viewer to each red, green and blue color, as is to be appreciated.
The power of an individual laser in a set may vary with design;
while the number of lasers in each laser set will vary with the
output power of individual lasers used in the set.
[0080] In embodiments, each laser in red laser set 12, green laser
set 14 and blue laser set 16 includes a sensor that provides
feedback regarding laser performance. For example, diode lasers in
red laser set 12 may include a photodiode chip that provides
optical feedback from each diode laser. Information from each
photosensor is then provided to control circuitry 150 to provide an
indication of laser output for each laser set.
[0081] FIG. 8 illustrates one or more lasers are installed on a
circuit board 430, which mounts, and provides electrical
communication for, each laser installed thereon. Five diode lasers
400a-e are installed thereon in accordance with embodiments, though
as noted above, any of the embodiments described herein as applied
to lasers or diode lasers can be adapted for use with LEDs, since
both act as a light source though with differing operating
parameters for the given laser or LED. This configuration of diode
lasers 400a-e reduces space for laser sets within display device
10. Control circuitry 412 on circuit board 430 regulates current
provided to each diode laser 400a-e. Although circuit board 430
shows five diode lasers 400, it is understood that circuit board
430 may include a combination of diode lasers 400 and DPSS lasers
450 as well as a different number of total light sources. In
embodiments, diode lasers 400a-e all output light having a similar
wavelength, such as red. In other embodiments, lasers on a single
board 430 output different colors.
[0082] In other embodiments, the total number of lasers in the set
of lasers, or LEDs as the case may be, is greater than a number of
lasers needed to produce the desired amount of light. Redundant
laser (or LED) supply is advantageous to prevent failure of an
individual laser from compromising output for the entire set, or
output for a given primary color. Correspondingly, each laser set
may continue to output its desired and intended luminous power and
primary color even though an individual laser in the set is no
longer operable. In most cases, this increases display device 10
longevity for a given set of lasers, with only a slight increase in
cost and size.
[0083] Periodic shutdown for each laser in a redundant set may also
be beneficial for heat dissipation. This allows individual lasers
to be heated less over the course of extended usage of display
device 10, such as usage associated with motion picture video
viewing. Shutdown for individual lasers in a set may be cyclical
based on a predetermined shutdown scheme. For example, in a four
laser redundant scheme where three lasers are needed for desired
output power in normal usage, each of the four lasers may take
turns shutting down for a predetermined time. This gives each laser
periodic time to cool, and results in less heat generation for each
laser.
[0084] Alternately, shutdown may be used to protect an individual
laser that is heating to a threshold temperature as sensed by a
temperature sensor disposed in proximity to the laser. Logic stored
in memory and accessible to control circuitry 76 (FIG. 5) then
shuts down the laser (and may turn on fans) to prevent the heating
laser from reaching the threshold temperature. Multiple threshold
temperatures may be established in this manner; and logic may be
implemented that determines which lasers in a redundant set are
used when multiple lasers in the set reach a particular threshold
temperature. It is to be understood that redundant laser supply
also advantageously increases longevity for individual lasers that
benefit from periodic shut-down, thereby also increasing longevity
for display device 10 on a given laser set.
[0085] In embodiments, each laser in sets 16 includes a temperature
sensor that detects the temperature of each laser in the set. As
described supra, control circuitry 76 uses feedback from the
temperature sensors to determine a) if any lasers are heating to
one or more temperature thresholds, and b) the specific temperature
of each diode laser to minimize temperature based wavelength drift.
Based on this information and stored instructions for each
condition, or multiple conditions, control circuitry 76 determines
which of the lasers in the set produce light based on the
temperature of each laser in the set. The stored logic may also
include instructions for special events, such as when multiple
lasers reach a predetermined temperature threshold, or when an
individual laser reaches a higher or dangerous temperature
threshold.
[0086] Some diode lasers 400 include a temperature based frequency
drift that alters the wavelength of output laser light with
temperature of the laser. Drift of 0.3 nanometers/degree Celsius
are common. Typically, a laser manufacturer knows temperature based
frequency drift for a given laser. In this case, redundant laser
supply may decrease any temperature-based drift by decreasing the
average temperature variation for each laser in a redundant set,
thereby increasing light consistency and image quality.
[0087] FIG. 9 shows a block diagram of a projection-type display
device 20 projecting images on a receiving surface 22 in accordance
with embodiments. Display device 20 comprises light source 210,
optical system 220, optical modulator 230, projection lenses 240,
control circuitry 250 and luminance sensor 252, temperature 254
sensor, and ambient light sensor 256. The luminance sensor 252 is a
light-sensitive device capable of capturing the image to be
projected. The luminance sensor 252 may be photodiode arrays,
charge-coupled device (CCD) camera or complementary metal oxide
semiconductor (CMOS) camera. However, any other light sensor or
camera with the desired light sensitivity may be useful as a
luminance sensor for the purposes of the light intensity detection.
The luminance sensor 252 may be incorporated with, connected to, or
otherwise associated with the projector.
[0088] In embodiments, the luminance sensor 252 may be mounted on
the receiving surface 22. Alternatively, the luminance sensor 252
may be attached to the projection-type display device 20, such as
by either mounting the luminance sensor 252 on the exterior of the
projection-type display device, or by incorporating the luminance
sensor 252 within the projection-type display device itself. In
either case, the luminance sensor 252 may be located so as to
minimize differences in the field of view of the sensor and the
area of the projected image.
[0089] In embodiments, the luminance sensor 252 shares at least a
portion of an optical path for both image projection and luminance
sensing. This may be accomplished, for example, by placing a beam
splitter 242 in the optical path of the projection lenses 240.
[0090] FIG. 10 illustrates an alternative example block diagram of
a projection-type display device 30 projecting images on a
receiving surface 32 in accordance with embodiments. Display device
30 is configured to produce and project a video image for display
on a receiving surface. Display device 30 comprises light source
310, optical system 320, optical modulator 330, projection lenses
340, control circuitry 350, luminance sensor 352, temperature
sensor 354, and ambient light sensor 356. Light source 310 includes
light source controller 318, circuit board 430, and laser sets.
Optical modulator 330 may include a plurality of movable minor
elements (not shown). The movable mirror elements move selectively
between a first reflecting position and a second reflecting
position in accordance with the image signal to reflect the
incident light toward the projector lens 340 or in the direction
other than that of the projector lens 340. The light advancing
toward the projector lens 340 forms a projection image on the
receiving surface 32.
[0091] The structure, in which the light intensity, or the outputs
of the laser sets is measured, allows the projection-type display
device 30 to respond to the physical change of the laser set to
control the light intensity. In some cases, the waste light, which
is not used for image formation, is used to measure the light
intensity. Alternatively, the sensor detects the amount of light
reflected by optical modulator 330. As described above, the light
intensity of the light source 310 may be controlled by the control
circuitry 350 in response to the sensor output.
[0092] FIG. 11 illustrates another example block diagram of a
projection-type display device 40 in accordance with embodiments.
Display device 40 comprises light source 410, optical system 420,
optical modulator 430, projection lenses 440, control circuitry
450, luminance sensor 452, temperature sensor 454 and ambient light
sensor 456. The light source 410 produces a desired amount of
light. The optical modulation 420 is configured to increase flux
area of the light. The optical modulator 430 is and light valve
with 3 LCDs. The luminance sensor 452 detects a real time reading
to measure an image projected by the projection-type display
device. The control circuitry 450 dynamically controls the light
source 410 based on the real time readings to dynamically vary the
luminance of the set of laser.
[0093] The ambient light sensor 456 detects the luminance of
ambient light of the projection environment. In accordance
therewith, the control circuitry 450 may increase the desired
amount of light if the luminance of ambient light exceeds a
predetermined lever, and/or decrease the desire amount of light if
the luminance of ambient light is less than the predetermined
level.
[0094] In other embodiments, the total number of lasers in the set
of lasers is greater than a number of lasers needed to produce the
desired amount of light. A temperature sensor 454 that detects the
temperature of the set of laser may be provided as shown. The
control circuitry 450 is configured to determine the subset of
lasers based on a temperature of each laser in the set of lasers.
For example, the control circuitry turns off the diode laser with
the highest temperature among the set of lasers. In other
embodiments, a timer for measuring the time the set of lasers
exceeds said predetermined amount is included in projection-type
display device. The control circuitry 450 operates to turn off from
a laser diode which has been ignited a predetermined period of
time.
[0095] Laser based systems described herein advantageously provide
a light generation option for projection-type display devices that
requires low voltage and consumes low power. Diode lasers are often
considered more efficient in terms of light generation per input
energy, particularly relative to white light lamps. Laser light
sources also generate less heat than a white light lamp, thereby
easing heat dissipation requirements. This allows for smaller
cooling fans that consume less power and require less space.
Another advantage of diode lasers is that diode lasers emit
relatively monochromatic colored light, thereby reduce (or
eliminate) a need for a color wheel and its spatial requirements.
It will be understood that eliminating the color wheel motor is
advantageous since it also occupies space, consumes power and
generates heat. Cumulatively, these factors each contribute to
significantly reduced power consumption for a display device and
enable battery-powered projection-type display devices.
[0096] Laser based designs described herein are also lighter and
require less space than white light lamp sources, which enables
projection-type display devices that are smaller, less weight, and
increasingly portable. In addition, the collimated light output
from lasers is significantly smaller in cross-sectional flux area
and therefore requires less space for optical manipulation, such as
smaller lenses, further saving space and reducing display device
size. In embodiments, display device 10 is less than 4 pounds. As
mentioned above, walls of housing 20 may comprise a lightweight and
stiff or rigid molded plastic, composite, alloy or metal that
reduces overall weight of display device 10. In other embodiments,
display device 10 is less than 2 pounds.
[0097] Display devices described herein also benefit from highly
collimated and substantially coherent light output. This permits
increased depth of focus for a projected image; and permits an
increased range of focus. For some display device designs, this may
eliminate a need for manual focusing tools and thereby further
reduce the size and cost of display device.
[0098] With respect to usage, a display device may receive analog
or digital video signals and data from a range of systems and
devices. In addition to personal computers such as desktop
computers and laptop computers, a variety of other computer systems
and digital devices may output video data to the display device.
Handheld computers, portable digital assistants (PDAs) and portable
digital devices are increasingly integrating video functionality,
including the ability to communicate with an external display
device. Other portable digital devices such as video games,
portable video games, portable digital video recorders and digital
cameras may also provide video output to display device described
herein.
[0099] One current trend is hybrid entertainment devices that
integrate the functionality of computer systems, stereos, and
televisions. In addition, set-top boxes associated with cable and
satellite television services are becoming much more sophisticated
user interfaces as interactive services become available to cable
customers. Any of these devices may employ and benefit from video
output using a display device as disclosed and claimed herein. The
scope of digital computer systems is expanding hurriedly and
creating many systems and devices that may employ some of the
embodiments. A merging of television, video, and computer functions
into a single device also adds value to the embodiments since the
sensitivity to image quality and size is high in applications such
as motion picture viewing. Moreover, it is to be appreciated that
the other embodiments may be practiced with other computer system
configurations, multiprocessor systems, microprocessor-based or
programmable consumer electronics, minicomputers, mainframe
computers, and the like.
[0100] Display devices may provide projected images having an image
size ranging from inches to many feet, as determined by a user and
environment. Image size for a projector typically depends on
mechanical factors such as the distance from the projector to the
receiving surface and a splay angle for the projection lens system
140 (FIG. 5). Display device 10 is well-suited for display of
motion pictures and still photographs onto screens. In addition,
display device 10 is also useful for conducting sales
demonstrations, playing video games, general computer usage,
business meetings, and classroom instruction, for example.
[0101] Although the foregoing paragraphs described some detail for
purposes of clarity of understanding, those skilled in the art will
recognize that various modifications may be made within the scope
of the appended claims. For example, although diode lasers
described herein have primarily been described with respect to side
emitting Fabry-Perot diode laser designs, it is understood that
other designs such as vertical cavity surface emitting diode
lasers, other vertical emitting and distributed feedback laser
designs may be used. Moreover, as was emphasized above, any of the
embodiments described in the context of lasers, or diode lasers,
are equally applicable to alternate embodiments that instead use
LEDs as the light source. In addition, optics may also be employed
to alter other unwanted laser beam characteristics not specifically
described above. For example, one or more wedge shaped prisms may
be used to alter or correct for any elliptical beam shape in a
laser beam, if present. By manipulating the relative orientations
of the prisms, the prisms may be used to shape or extend the beam
profile in one more directions.
[0102] Further, although some embodiments has been described with
respect to fiber-optic cabling for transmission of light between
sets of lasers and relay optics that deliver the light to the
optical modulator, it is understood that fiber-optic cabling is not
always necessary. In embodiments, sets of lasers are arranged to
emit light towards optics system, which converts incoming light to
a light flux suitable for transmission onto optical modulator and
transmits the light to an optical modulator without the use of
fiber-optic cabling. For example, the lasers may be arranged to
emit light towards a first lens that spans the laser light from
each laser onto a first fly-eye lens.
[0103] What has been described above includes examples of the
innovation. It is, of course, not possible to describe every
conceivable combination of components or methodologies for purposes
of describing the subject innovation, but one of ordinary skill in
the art may recognize that many further combinations and
permutations of the innovation are possible. Accordingly, the
innovation is intended to embrace all such alterations,
modifications and variations that fall within the spirit and scope
of the appended claims. Furthermore, to the extent that the term
"includes" is used in either the detailed description or the
claims, such term is intended to be inclusive in a manner similar
to the term "comprising" as "comprising" is interpreted when
employed as a transitional word in a claim.
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