# US 10,310,317 B2 · Light modulation element unit having a light modulating element and image projection apparatus for preventing foreign matters from adhering to light modulation element

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- Number: US 10,310,317 B2
- Document ID: US10310317B2
- Status: Granted
- Kind: B2
- Application number: 15/147,433
- Filed: 2016-05-05
- Published: 2016-11-17
- Granted: 2019-06-04
- Earliest claimed: 2015-05-15
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Koichi Yusa; Toshiyuki Noda
- Web page: https://patentgrep.com/patent/US10310317B2

## CPC

- G02F 1/133382: {Heating or cooling of liquid crystal cells other than for activation, e.g. circuits or arrangements for temperature control, stabilisation or uniform distribution over the cell}
- G02F 1/133308: {Support structures for LCD panels, e.g. frames or bezels}
- G02F 1/133385: {with cooling means, e.g. fans}
- G02F 1/1335: Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F 1/133509: {Filters, e.g. light shielding masks}
- G02F 1/133512: {Light shielding layers, e.g. black matrix (G02F1/136209 takes precedence)}
- G03B 21/006: {using LCD's}
- G03B 21/16: Cooling; Preventing overheating
- H04N 5/7441: {the modulator being an array of liquid crystal cells}
- H04N 9/3102: {using two-dimensional electronic spatial light modulators (micromechanical modulators as such G02B26/0833; liquid crystal modulators as such G02F1/13)}
- H04N 9/3141: {Constructional details thereof (details not peculiar to the presence of an electronic spatial light modulator G03B21/14)}
- H04N 9/3144: {Cooling systems (cooling of liquid crystal cells in general G02F1/133382; cooling of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/16)}
- H04N 9/3152: {for shaping the light beam (beam shaping per se G02B27/09)}
- H04N 9/317: {Convergence or focusing systems (electronic adjustment of convergence H04N9/3185; convergence or focusing arrangements for cathode ray tubes H04N9/28; means for automatic focusing of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/53)}
- G02F 1/133388: {with constructional differences between the display region and the peripheral region}
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A light modulation element unit includes a light modulation element having a light modulator configured to modulate incident light and a cover glass that covers a light incident surface of the light modulator, a light shielding member, disposed along a surface of the cover glass, which has an opening in which light going to the light modulator passes and a light shield configured to shield light that does not pass the opening, and a heat radiation member provided in a direction different from a direction of the cover glass with respect to the light modulation element. The light shielding member has an extension that extends to outside of the cover glass and faces the heat radiation member. A first gap between the extension and the heat radiation member is smaller than a second gap between the light shield and the surface of the cover glass.

## Claims

### Claim 1

A light modulation element unit comprising:
a light modulation element having a light modulator configured to modulate incident light and a cover glass that covers a light incident surface of the light modulator and that has a first light incident surface facing the light incident surface of the light modulator and a second light incident surface positioned on an opposite side to the first light incident surface;
a light shielding member, which is disposed along the second light incident surface of the cover glass, and has an opening through which light going toward the light modulator passes and a light shield to shield light that does not pass the opening; and
a heat radiation member that is separate from the light shielding member provided on an opposite side of the cover glass with respect to the light modulation element,
wherein the light shielding member further has an extension that extends to outside of the cover glass and that faces part of the heat radiation member with a first air gap,
wherein the light shield is disposed along part of the second light incident surface of the cover glass with a second air gap,
wherein the part of the second light incident surface of the cover glass is configured to communicate air through the first air gap and the second air gap, and
wherein the first air gap is smaller than the second air gap.

### Claim 2 (depends on 1)

The light modulation element unit according to claim 1, wherein:
the part of the heat radiation member has a convex that projects toward the light shielding member outside the cover glass, and
the first air gap is between the extension and the convex, and the second air gap is between the light shield and the second light incident surface of the cover glass.

### Claim 3 (depends on 1)

The light modulation element unit according to claim 1, wherein:
the light shielding member is made of a first material, and
the light modulation element unit further includes a support member made of a second material having a thermal conductivity higher than that of the first material, and configured to support the light shielding member, and attached to the heat radiation member.

### Claim 4 (depends on 3)

The light modulation unit according to claim 3, wherein the light shielding member and the support member are coupled with each other with spot welding.

### Claim 5 (depends on 1)

The light modulation unit according to claim 1, wherein:
the light modulation element has a wiring connected to a side surface when a surface where the cover glass is provided is set to a front surface, and the wiring is configured to transmit a signal to the light modulation element, and
the extension is provided opposite to the wiring with respect to the light modulation element.

### Claim 6 (depends on 1)

The light modulation unit according to claim 1, wherein a temperature gradient in the first air gap is larger than that in the second air gap.

### Claim 7 (depends on 1)

The light modulation element unit according to claim 1, wherein:
the extension is disposed closer to the heat radiation member than the light shield, and
the first air gap is between the extension and a surface of the heat radiation member, and the second air gap is between the light shield and the second light incident surface of the cover glass.

### Claim 8 (depends on 1)

The light modulation element unit according to claim 1, wherein the first air gap and the second air gap permit cooling air to flow.

### Claim 9

An image projection apparatus comprising:
a light modulation element unit comprising:
a light modulation element having a light modulator configured to modulate incident light and a cover glass that covers a light incident surface of the light modulator and that has a first light incident surface facing the light incident surface of the light modulator and a second light incident surface positioned on an opposite side to the first light incident surface;
a light shielding member disposed along the second light incident surface of the cover glass and has an opening through which light going toward the light modulator passes and a light shield to shield light that does not pass the opening; and
a heat radiation member that is separate from the light shielding member provided on an opposite side of the cover glass with respect to the light modulation element,
wherein the light shielding member further has an extension that extends to outside of the cover glass and that faces part of the heat radiation member with a first air gap,
wherein the light shield is disposed along part of the second light incident surface of the cover glass with a second air gap,
wherein the part of the second light incident surface of the cover glass is configured to communicate air through the first air gap and the second air gap, and
wherein the first air gap is smaller than the second air gap; and
an optical system configured to introduce light from a light source to the light modulation element, and project the light that is modulated by the light modulation element onto a target plane.

### Claim 10 (depends on 9)

The image projection apparatus according to claim 9, further comprising:
a cooler configured to flow air to the light modulation element unit,
wherein the extension is provided upstream of the cover glass in a flow of the air.

### Claim 11

A light modulation element unit comprising:
a light modulation element having a light modulator configured to modulate incident light and a cover glass that covers a light incident surface of the light modulator and that has a first light incident surface facing the light incident surface of the light modulator and a second light incident surface positioned on an opposite side to the first light incident surface;
a light shielding member, which is disposed along the second light incident surface of the cover glass, and has an opening through which light going toward the light modulator passes and a light shield to shield light that does not pass the opening; and
a heat radiation member that is separate from the light shielding member provided on an opposite side of the cover glass with respect to the light modulation element,
wherein the light shielding member further has an extension that extends to outside of the cover glass and that faces part of the heat radiation member with a first air gap,
wherein the light shield is disposed along part of the second light incident surface of the cover glass with a second air gap,
wherein the part of the second light incident surface of the cover glass is configured to communicate air through the first air gap and the second air gap, and
wherein a temperature gradient of the first air gap is larger than a temperature gradient of the second air gap.

### Claim 12

An image projection apparatus comprising:
a light modulation element unit comprising:
a light modulation element having a light modulator configured to modulate incident light and a cover glass that covers a light incident surface of the light modulator and that has a first light incident surface facing the light incident surface of the light modulator and a second light incident surface positioned on an opposite side to the first light incident surface;
a light shielding member disposed along the second light incident surface of the cover glass and has an opening through which light going toward the light modulator passes and a light shield to shield light that does not pass the opening; and
a heat radiation member that is separate from the light shielding member provided on an opposite side of the cover glass with respect to the light modulation element,
wherein the light shielding member further has an extension that extends to outside of the cover glass and that faces part of the heat radiation member with a first air gap,
wherein the light shield is disposed along part of the second light incident surface of the cover glass with a second air gap,
wherein the part of the second light incident surface of the cover glass is configured to communicate air through the first air gap and the second air gap, and
wherein a temperature gradient of the first air gap is larger than a temperature gradient of the second air gap; and
an optical system configured to introduce light from a light source to the light modulation element, and to project the light that is modulated by the light modulation element onto a target plane.

### Claim 13 (depends on 12)

The image projection apparatus according to claim 12, further comprising:
a cooler configured to flow air to the light modulation element unit,
wherein the extension is provided upstream of the cover glass in a flow direction of air.