JP4540298B2 - Image display device and image display method - Google Patents

Description

【００２９】
上記（１）式において、Ｃ_ｎは、光源ＬｎのＲ，Ｇ，Ｂ発光体の発光量（Ｒ_Ｌｎ，Ｇ_Ｌｎ，Ｂ_Ｌｎ）と、光源Ｌｎの三刺激値（Ｘ_Ｌｎ，Ｙ_Ｌｎ，Ｚ_Ｌｎ）との相関を示す３×３の行列である。この相関行列Ｃ_ｎは、光源ごとに固有の行列であって、実際の測定などによってあらかじめ求めることができる。
【００３０】
また、表示部１１の一部のエリアＡｍにおいての光は、４つの光源Ｌ１〜Ｌ４のそれぞれから固有の減衰率でエリアＡｍに到達した光の混合光である。このようなエリアＡｍにおいての光の三刺激値（Ｘ_Ａｎ，Ｙ_Ａｎ，Ｚ_Ａｎ）は、次の（２）式のように表される。
【数２】

【００３１】
上記（２）式において、ｋ_ｍｎは光源Ｌｎからの光がエリアＡｍに到達するまでの減衰率を表す係数である。なお、上記（２）式では、光源ＬｎからのＸ，Ｙ，Ｚ光の減衰率係数を全て同じ値ｋ_ｍｎとしているが、上記Ｘ，Ｙ，Ｚ光の減衰率が異なる場合は、上記減衰率係数ｋ_ｍｎは上記Ｘ，Ｙ，Ｚ光それぞれに固有の値となる。
【００３２】
上記（２）式の第ｎ項は、エリアＡｍにおいての光源Ｌｎの発光量の寄与率を表す。光源Ｌ１〜Ｌ４を全て発光させた場合は、エリアＡｍにおいての光の三刺激値（Ｘ_Ａｍ，Ｙ_Ａｍ，Ｚ_Ａｍ）は、上記（２）式の第１項〜第４項を全て加算したものとなる。また、例えば光源Ｌ１のみを発光させた場合は、エリアＡｍにおいての光の三刺激値（Ｘ_Ａｍ，Ｙ_Ａｍ，Ｚ_Ａｍ）は、上記（２）式の第１項となる。
【００３３】
また、カラーセンサーＳｍは、エリアＡｍにおいての光を検出する。エリアＡｍにおいての光の三刺激値と、カラーセンサーＳｍのＲ，Ｇ，Ｂ検出光量との間には相関がある。エリアＡｍにおいての光の三刺激値を（Ｘ_Ａｍ，Ｙ_Ａｍ，Ｚ_Ａｍ）とすると、カラーセンサーＳｍの分光感度特性がルータ条件を満たすとき、カラーセンサーＳｍのＲ，Ｇ，Ｂ検出光量（Ｒ_Ｓｍ，Ｇ_Ｓｍ，Ｂ_Ｓｍ）は、次の（３）式のように表される。
【数３】

【００３４】
上記（３）式において、Ｄ_ｍは、エリアＡｍにおいての光の三刺激値（Ｘ_Ａｍ，Ｙ_Ａｍ，Ｚ_Ａｍ）と、カラーセンサーＳｍの検出光量（Ｒ_Ｓｍ，Ｇ_Ｓｍ，Ｂ_Ｓｍ）との相関を表す３×３の行列である。この相関行列Ｄ_ｍは、例えばエリアごと（カラーセンサーごと）に固有の行列であって、実際の測定などによってあらかじめ求めることができる。
【００３５】
上記（１）式〜（３）式を組合せることにより、４つの光源Ｌ１〜Ｌ４のＲ，Ｇ，Ｂ色発光体の発光量（Ｒ_Ｌ１，Ｇ_Ｌ１，Ｂ_Ｌ１）〜（Ｒ_Ｌ４，Ｇ_Ｌ４，Ｂ_Ｌ４）と、カラーセンサーＳｍの検出光量（Ｒ_Ｓｍ，Ｇ_Ｓｍ，Ｂ_Ｓｍ）との相関を表す次の（４）式を導出できる。
【数４】

【００３６】
上記（４）式において、Ｅ_ｍｎは、光源ＬｎのＲ，Ｇ，Ｂ発光体の発光量（Ｒ_Ｌｎ，Ｇ_Ｌｎ，Ｂ_Ｌｎ）と、カラーセンサーＳｍの検出光量（Ｒ_Ｓｍ，Ｇ_Ｓｍ，Ｂ_Ｓｍ）との相関を示す３×３の行列であって、Ｅ_ｍｎ＝Ｄ_ｍ×ｋ_ｍｎ×Ｃ_ｎである。
【００３７】
上記（４）式の第ｎ項は、カラーセンサーＳｍの検出光量（Ｒ_Ｓｍ，Ｇ_Ｓｍ，Ｂ_Ｓｍ）においての光源Ｌｎの発光量の寄与率を表す。光源Ｌ１〜Ｌ４を全て発光させた場合は、カラーセンサーＳｍの検出光量（Ｒ_Ｓｍ，Ｇ_Ｓｍ，Ｂ_Ｓｍ）は、上記（４）式の第１項〜第４項を全て加算したものとなる。また、例えば光源Ｌ１のみを発光させた場合は、カラーセンサーＳｍの検出光量（Ｒ_Ｓｍ，Ｇ_Ｓｍ，Ｂ_Ｓｍ）は、上記（４）式の第１項となる。
【００３８】
相関行列Ｅ_１ｍ〜Ｅ_４ｍは、光源Ｌ１〜Ｌ４の内の光源ＬｍのＲ，Ｇ，Ｂ発光体のいずれか１つのみを単独で発光させたときのその発光体の発光量およびカラーセンサーＳ１〜Ｓ４の検出光量（Ｒ_Ｓ１，Ｇ_Ｓ１，Ｂ_Ｓ１）〜（Ｒ_Ｓ４，Ｇ_Ｓ４，Ｂ_Ｓ４）をもって、あらかじめ求めることができる。
【００３９】
例えば、光源Ｌ１のＲ発光体のみを発光させときのその発光体の発光量Ｒ_Ｌ１およびカラーセンサーＳ１〜Ｓ４の検出光量（Ｒ_Ｓ１，Ｇ_Ｓ１，Ｂ_Ｓ１）〜（Ｒ_Ｓ４，Ｇ_Ｓ４，Ｂ_Ｓ４）をもって、相関行列Ｅ_１１〜Ｅ_４１の第１列の３つの値を求めることができ、光源Ｌ１のＧ発光体のみを発光させときのその発光体の発光量Ｇ_Ｌ１およびカラーセンサーＳ１〜Ｓ４の検出光量（Ｒ_Ｓ１，Ｇ_Ｓ１，Ｂ_Ｓ１）〜（Ｒ_Ｓ４，Ｇ_Ｓ４，Ｂ_Ｓ４）をもって、相関行列Ｅ_１１〜Ｅ_４１の第２列の３つの値を求めることができ、光源Ｌ１のＢ発光体のみを発光させときのその発光体の発光量Ｂ_Ｌ１およびカラーセンサーＳ１〜Ｓ４の検出光量（Ｒ_Ｓ１，Ｇ_Ｓ１，Ｂ_Ｓ１）〜（Ｒ_Ｓ４，Ｇ_Ｓ４，Ｂ_Ｓ４）をもって、相関行列Ｅ_１１〜Ｅ_４１の第３列の３つの値を求めることができる。
【００４０】
あらかじめ求めた相関行列Ｅ_１１〜Ｅ_４４を上記（４）式に代入することにより、カラーセンサーＳ１〜Ｓ４の合計１２の検出光量Ｒ_Ｓ１〜Ｂ_Ｓ４のそれぞれについて、光源Ｌ１〜Ｌ４のＲ，Ｇ，Ｂ発光体の発光量Ｒ_Ｌ１〜Ｂ_Ｌ４との相関式がそれぞれ得られる。
【００４１】
あらかじめ求めた上記合計１２の相関式に、カラーセンサーＳ１〜Ｓ４の合計１２の検出光量Ｒ_Ｓ１〜Ｂ_Ｓ４をそれぞれ代入することにより、光源Ｌ１〜Ｌ４のＲ，Ｇ，Ｂ発光体の合計１２の発光量Ｒ_Ｌ１〜Ｂ_Ｌ４を変数とする１２の式からなる連立方程式が得られ、この連立方程式を解くことにより、光源Ｌ１〜Ｌ４のＲ，Ｇ，Ｂ発光体の発光量（検出発光量）Ｒ_Ｌ１〜Ｂ_Ｌ４のそれぞれを算出することができる。
【００４２】
このように、上記（４）式から得られる合計１２の相関式を用いることにより、カラーセンサーＳ１〜Ｓ４の検出光量Ｒ_Ｓ１〜Ｂ_Ｓ４から、光源Ｌ１〜Ｌ４のＲ，Ｇ，Ｂ発光体の発光量（検出発光量）Ｒ_Ｌ１〜Ｂ_Ｌ４を算出することができる。
【００４３】
図３は本発明の実施の形態の画像表示装置においての光源校正手順を示すフローチャートである。この図３を用いて本実施の形態の光源校正手順について以下に説明する。
【００４４】
相関データメモリ２４には、上記（４）式の相関行列Ｅ_１１〜Ｅ_４４の値があらかじめ記憶されている。これらの相関行列Ｅ_１１〜Ｅ_４４の値は、設計段階や生産段階などにおいて実際の測定値などを用いて設定される。また、上記（４）式から得られた上記合計１２の上記相関式も、上記検出発光量Ｒ_Ｌ１〜Ｂ_Ｌ４の演算アルゴリズムの一部として相関データメモリ２４に記憶されている。
【００４５】
従って、相関データメモリ２４には、上記（４）式から得られた上記合計１２の上記相関式であって、上記（４）式の相関行列Ｅ_１１〜Ｅ_４４の値が判っているものが、相関データとしてあらかじめ記憶されている。なお、上記演算アルゴリズムを光源発光量演算部２３に記憶しておくことも可能である。
【００４６】
また、光源基準発光量データメモリ２５には、それぞれの光源のそれぞれの発光体の基準発光量で構成された光源基準発光量データがあらかじめ記憶されている。この光源基準発光量データは、全域に色ムラや輝度ムラのない画面が得られるときのそれぞれの光源のそれぞれの発光体の発光量データであり、設計段階や生産段階（生産段階においての光源発光量の初期設定時）などにおいて設定される。
【００４７】
さらに、光源基準発光量データメモリ２５には、基準発光量データに対する検出発光量データの許容範囲があらかじめ記憶されている。この許容範囲は、例えば画像表示装置の表示品質や使用目的などに応じて、設計段階や生産段階などにおいて設定される。
【００４８】
図３において、光源校正の開始時に、光源Ｌ１〜Ｌ４が発光していればすぐにステップ１に進み、光源Ｌ１〜Ｌ４が発光していなければ、光源制御部２０の光源制御量演算部２６によって光源駆動部２１を制御し、光源駆動部２１によって光源Ｌ１〜Ｌ４を発光させ、必要に応じて光源が安定するまで待機してからステップ１に進む。この光源校正は、ユーザーが任意のタイミングで開始させることが可能である他、所定の時間間隔や所定の時刻になされるように自動設定しておくことも可能である。
【００４９】
ステップ１では、カラーセンサーＳ１によってエリアＡ１においてのＲ，Ｇ，Ｂ光量を、カラーセンサーＳ２によってエリアＡ２においてのＲ，Ｇ，Ｂ光量を、カラーセンサーＳ３によってエリアＡ３においてのＲ，Ｇ，Ｂ光量を、それぞれ検出する。
【００５０】
そして、これらカラーセンサーＳ１のＲ，Ｇ，Ｂ検出光量（Ｒ_Ｓ１，Ｇ_Ｓ１，Ｂ_Ｓ１）、カラーセンサーＳ２のＲ，Ｇ，Ｂ検出光量（Ｒ_Ｓ２，Ｇ_Ｓ２，Ｂ_Ｓ２）、カラーセンサーＳ３のＲ，Ｇ，Ｂ検出光量（Ｒ_Ｓ３，Ｇ_Ｓ３，Ｂ_Ｓ３）、およびカラーセンサーＳ４のＲ，Ｇ，Ｂ検出光量（Ｒ_Ｓ４，Ｇ_Ｓ４，Ｂ_Ｓ４）をＡ／Ｄ変換部２２に送出し、Ａ／Ｄ変換部２２において、ディジタル値に変換する。
【００５１】
次のステップ２では、Ａ／Ｄ変換部２２でディジタル値に変換された検出光量データを光源制御部２０の光源発光量演算部２３に送出し、光源発光量演算部２３において、相関データメモリ２４に記憶されている上記合計１２の相関式を用いて、合計１２の検出光量Ｒ_Ｓ１〜Ｂ_Ｓ４から、光源Ｌ１のＲ，Ｇ，Ｂ発光体の検出発光量（Ｒ_Ｌ１，Ｇ_Ｌ１，Ｂ_Ｌ１）、光源Ｌ２のＲ，Ｇ，Ｂ発光体の検出発光量（Ｒ_Ｌ２，Ｇ_Ｌ２，Ｂ_Ｌ２）、光源Ｌ３のＲ，Ｇ，Ｂ発光体の検出発光量（Ｒ_Ｌ３，Ｇ_Ｌ３，Ｂ_Ｌ３）、および光源Ｌ４のＲ，Ｇ，Ｂ発光体の検出発光量（Ｒ_Ｌ４，Ｇ_Ｌ４，Ｂ_Ｌ４）を算出する。
【００５２】
次のステップ３では、光源発光量演算部２３で算出された検出発光量データを光源制御量演算部２６に送出し、光源制御量演算部２６において、それぞれの光源のそれぞれの発光体について、検出発光量とメモリ２５に記憶されている基準発光量との差分を求め、その差分をメモリ２５に記憶されている許容範囲と比較する。そして、いずれかの発光体の上記差分が上記許容範囲を超えている場合にはステップ４に進む。
【００５３】
ステップ４では、許容範囲を超えている検出発光量が基準発光量よりも小さい場合はその発光体の発光量を増やす方向にその発光体の制御量を変更し、許容範囲を超えている検出発光量が基準発光量よりも大きい場合はその発光体の発光量を減らす方向にその発光体の制御量を変更し、これらの光源制御データを光源駆動部２１に送出する。
【００５４】
そして、光源駆動部２１において、上記制御量が変更された光源制御データに従って、それぞれの光源のそれぞれの発光体の発光量を再調整したあと、再び上記ステップ１〜３を実施する。
【００５５】
このようにして、それぞれの光源のそれぞれの発光量を調整し、上記ステップ３で、全ての光源の全ての発光体について検出発光量と基準発光量の差分が許容範囲内に収まっていれば、この光源校正手順を終了する。
【００５６】
以上のように本発明の実施の形態によれば、複数のカラーセンサーそれぞれの検出光量と複数の光源それぞれの発光量との間の相関式を用いて、上記検出光量からそれぞれの光源の検出発光量を算出し、これらの検出発光量をもとにそれぞれの光源の発光量を調整することにより、複数の光源からの光によって画面上に画像を表示する非自発光型の構成において画像品質を劣化させずに画面の色度や輝度および画面内の色ムラや輝度ムラを容易に校正することができる。
【００５７】
さらに、上記従来の画像表示装置では、カラーセンサーが１つのためにカラーセンサーを画面の中央に設置する必要があり、カラーセンサーを画像表示の妨げになる位置に設置しなければならないので、光源校正を随時実施することが困難であったが、この実施の形態の画像表示装置では、複数カラーセンサーによって画面上の互いに異なる一部のエリアの光量をそれぞれ検出しているので、それぞれのカラーセンサーを画面の周辺に設けることができ、カラーセンサーを画像表示の妨げにならない位置に設置できるので、光源校正を随時実施することができる。
【００５８】
なお、上記実施の形態では、４つの光源を備えた画像表示装置において４つのカラーセンサーを設けているが、カラーセンサーの個数を光源の個数以上とすれば上記（４）式を用いて光源の発光体の検出発光量を算出することができるので、カラーセンサーの個数は光源の個数と同じかそれよりも多い個数とすることが可能である。
【００５９】
また、上記実施の形態では、階調特性が線形であることを前提としているが、光源あるいはカラーセンサー等の特性によって階調特性が線形でない場合には、あらかじめその階調特性を測定などによって得た上で、上記（４）式の相関式に盛り込むことにより、同様に光源の発光量を算出することができる。
【００６０】
【発明の効果】
以上説明したように本発明によれば、複数の光源からの光によって画面上に画像を表示する非自発光型の構成において画像品質を劣化させずに画面の色度や輝度および画面内の色ムラや輝度ムラを容易に校正することができるという効果がある。
【図面の簡単な説明】
【図１】 本発明の実施の形態の画像表示装置においてのディスプレイパネルの構成図である。
【図２】 本発明の実施の形態の画像表示装置においての光源校正のための構成および光源校正手順を説明する図である。
【図３】 本発明の実施の形態の画像表示装置においての光源校正手順を示すフローチャートである。
【符号の説明】
１１ 表示部、 １２ 導光板、 Ｌ１，Ｌ２，Ｌ３，Ｌ４ 光源、 Ｓ１，Ｓ２，Ｓ３，Ｓ４ カラーセンサー、 ２０ 光源制御部、 ２１ 光源駆動部、 ２２ Ａ／Ｄ変換部、 ２３ 光源発光量演算部、 ２４ 相関データメモリ、 ２５ 光源基準発光量データメモリ、 ２６ 光源制御量演算部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image display device and an image display method, and in particular, in a non-self-luminous configuration in which an image is displayed on a screen by light from a plurality of light sources, chromaticity and brightness of the screen, and color unevenness and brightness unevenness in the screen. The present invention relates to an image display device and an image display method that can easily calibrate the image.
[0002]
[Prior art]
As a conventional image display device having a function of correcting variations in chromaticity and luminance of a screen, the chromaticity and luminance of the screen are detected by a single color sensor, and the above chromaticity and luminance are detected based on the detected data. There was a thing which corrects (for example, refer to patent documents 1). In addition, there is one that detects the chromaticity and luminance of the screen by a single color sensor, and corrects and controls the color adjustment of the image processing in accordance with the variation amount of the detected value from the logical value (for example, see Patent Document 2). .
[0003]
On the other hand, as a conventional non-self-luminous image display device that displays an image on a screen by light from a light source, a light source is composed of light emitters of a plurality of colors, and light from different color light emitters is mixed. Accordingly, there is an apparatus that functions as a light source and adjusts the chromaticity and luminance of a display screen by individually controlling the light emission amount of each color light emitter. Furthermore, there are some provided with a plurality of the light sources.
[0004]
For example, in a non-self-luminous flat panel display such as a liquid crystal display that transmits light from a light source such as a backlight and displays an image on a screen, R (Red), G (Green), and B (Blue) 3 There is one in which one or a plurality of light sources are constituted by a plurality of color light emitters each formed by arranging a plurality of color LEDs.
[0005]
In such a non-self-luminous image display device, the amount of light emitted from the light emitter of the light source varies with time, and the amount of variation in the amount of light emitted from the light emitter of each color varies. Since the luminance fluctuates and color unevenness or luminance unevenness occurs in the screen, it is necessary to calibrate chromaticity, luminance, color unevenness, or luminance unevenness.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-281531 (FIG. 1)
[Patent Document 2]
JP 2002-64842 A (FIGS. 1 and 3)
[0007]
[Problems to be solved by the invention]
However, the conventional image display device that corrects the variation in chromaticity and luminance is applied to the non-self-luminous conventional image display device that includes the plurality of light sources, so that adjustment of chromaticity and luminance and color unevenness are applied. When correcting brightness unevenness, there are the following problems.
[0008]
Since the chromaticity and brightness of the screen where light from multiple light sources are mixed are detected by a single color sensor, the correlation between the detected data and each light source is not taken into account, and the adjustment processing of chromaticity and brightness diverges. There was a possibility. In order to prevent such divergence of adjustment processing, it is necessary to detect the chromaticity and luminance by individually emitting light from each light source. Since detection in the area is necessary, it takes time and effort to detect the light amount and adjust the light emission amount.
[0009]
In addition, a conversion error, a bit drop, or the like occurs in image processing depending on the degree of variation, and image quality may be deteriorated separately from correction of color unevenness and brightness unevenness.
[0010]
The present invention has been made to solve such a conventional problem, and in a non-self-luminous configuration in which an image is displayed on the screen by light from a plurality of light sources, the image quality is not deteriorated. It is an object of the present invention to provide an image display apparatus and an image display method capable of easily calibrating the chromaticity and luminance of the image and the color unevenness and luminance unevenness in the screen.
[0011]
[Means for Solving the Problems]
The image display device of the present invention is
In an image display device that displays an image on a screen by a plurality of light sources each capable of adjusting light emission chromaticity and light emission luminance,
A plurality of color sensors that respectively detect chromaticity and luminance for different areas on the screen;
Correlation storage means for storing a correlation equation between the detected chromaticity and detected luminance of each of the color sensors and the emitted chromaticity and emitted luminance of each of the light sources;
An arithmetic means for calculating the detected light emission chromaticity and the detected light emission luminance of each light source from the detected chromaticity and the detected luminance using the correlation equation;
And adjusting means for adjusting the light emission chromaticity and the light emission luminance of each of the light sources based on the detected light emission chromaticity and the detection light emission luminance.
[0012]
The image display method of the present invention includes:
In an image display method for displaying an image on a screen by a plurality of light sources each capable of adjusting light emission chromaticity and light emission brightness,
A first step of detecting chromaticity and luminance by a plurality of color sensors for different areas on the screen;
Using the correlation equation between the detected chromaticity and detected luminance of each of the color sensors and the emitted chromaticity and emitted luminance of each of the light sources, the detected emitted chromaticity of each of the light sources and the detected chromaticity and A second step of calculating the detected emission luminance;
And a third step of adjusting the light emission chromaticity and light emission luminance of each of the light sources based on the detected light emission chromaticity and the detection light emission luminance.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a configuration diagram of a display panel in an image display apparatus according to an embodiment of the present invention. FIG. 2 is a diagram for explaining a configuration for light source calibration and a light source calibration procedure in the image display apparatus according to the embodiment of the present invention.
[0014]
1 and 2, the image display apparatus according to this embodiment is a non-self-luminous image display apparatus such as a liquid crystal display, and includes a display unit 11 of a display panel, a light guide plate 12 of the display panel, and a display. The panel includes four light sources L1, L2, L3, and L4, four color sensors S1, S2, S3, and S4, a light source control unit 20, a light source driving unit 21, and an A / D conversion unit 22. . The light source control unit 20 includes a light source emission amount calculation unit 23, a correlation data memory 24, a light source reference emission amount data memory 25, and a light source control amount calculation unit 26.
[0015]
The light source Ln (n is an arbitrary value of 1, 2, 3 and 4) is composed of an R (Red) light emitter, a G (Green) light emitter, and a B (Blue) light emitter. For example, an R light emitter is an array of R LEDs, a G light emitter is a G LED, and a B light emitter is a B LED. The light source Ln can individually adjust the light emission amounts of the R light emitter, the G light emitter, and the B light emitter (R channel, G channel, B channel) independently.
[0016]
R, G, B light from the three color light emitters of the light source Ln is controlled for each pixel, mixed by the light guide plate 12 and diffused to the display unit 11, whereby a color image is displayed on the display unit 11. Is displayed.
[0017]
The color sensor Sm (m is an arbitrary value of 1, 2, 3, and 4) is disposed around the display unit 11 and in the vicinity of a part of the area Am on the display unit 11. Light amounts of R, G, B3 colors (R, G, B3 channels) in the area Am of light from the light sources L1 to L4 mixed by the light guide plate 12 are detected, and the detected light amounts of these R, G, B3 channels are detected. The data is output to the A / D converter 22. Since the chromaticity and luminance in the area Am are known from the detected light amounts of the three channels, the color sensor Sm detects the chromaticity and luminance in the area Am, and A / D converts the detected chromaticity and detected luminance. In other words, the data is output to the unit 22.
[0018]
Here, each of the partial areas A1, A2, A3, and A4 on the display unit 11 is expressed as being clearly divided by a dotted line in FIG. 1, but this is only the position of the area. The range actually detected by each color sensor is not clearly divided in this way.
[0019]
Further, when installing the color sensors S1 to S4, in order to eliminate detection errors other than light from the light sources L1 to L4, it is desirable to have a structure that blocks incident light other than light from the light sources L1 to L4. .
[0020]
The light source drive unit 21 individually drives each light emitter of each light source, and individually determines the light emission amount of each light emitter according to the light source control data from the light source control amount calculation unit 26 of the light source control unit 20. Control.
[0021]
The A / D conversion unit 22 converts the analog value of the detected light amount output from each color sensor into a digital value, and outputs the detected light amount data to the light source emission amount calculation unit 23 of the light source control unit 20.
[0022]
In the light source control unit 20, the correlation data memory 24 stores between the detected light amounts of the R, G, and B channels of the respective color sensors and the light emission amounts of the R, G, and B channels of the respective light sources L 1 to L 4. The correlation data is stored in advance. The correlation data is also correlation data between the detection chromaticity and detection luminance of each color sensor and the emission chromaticity and emission luminance of each light source.
[0023]
The light source emission amount calculation unit 23 uses the correlation data stored in the correlation data memory 24 to calculate the detected emission amounts of the R, G, and B channels of the respective light sources from the detected light amounts of the respective color sensors. The detected light emission amount data is output to the light source control amount calculation unit 26. In other words, the light source emission amount calculation unit 23 may calculate the detected emission chromaticity and the detected emission luminance of each light source from the detected chromaticity and the detected luminance of each of the color sensors.
[0024]
The light source reference light emission amount data memory 25 stores light source reference light emission amount data composed of reference light emission amounts of the respective light emitters of the respective light sources in advance. The light source reference light emission amount data is data composed of the reference light emission chromaticity and the reference light emission luminance of each light source.
[0025]
The light source control amount calculation unit 26 compares the detected light emission amount data for each light emitter of each light source with the light source reference light emission amount data for that light emitter stored in the memory 25, and the light emission. Light source control data for controlling the light emission amount of the light emitter is output to the light source drive unit 21 so that the light emission amount of the body matches the reference light emission amount.
[0026]
The light emission amounts of the respective light emitters of the respective light sources are initially set so that the chromaticity and the luminance are uniform over the entire screen of the display unit 11 and there is no color unevenness or luminance unevenness. However, due to the variation with time of the light emission luminance of each light emitter and the variation with time of the light emitter, the uniformity of chromaticity and luminance within the screen is lost, resulting in color unevenness and luminance unevenness. In particular, if there is a variation in the temporal change among the R, G, and B light emitters, a change in chromaticity appears remarkably, and the visibility decreases. For this reason, it is necessary to calibrate the amount of light emitted from each illuminant of each light source to maintain the uniformity of chromaticity and luminance within the screen as in the initial setting.
[0027]
The procedure for light source calibration in the image display apparatus of this embodiment will be described below. The light source calibration procedure of this embodiment is characterized by using a correlation between the detected light amount of each channel of each color sensor and the emitted light amount of each light emitter of each light source. First, the correlation between the amount of light detected by the color sensor and the amount of light emitted from the light source will be described.
[0028]
First, there is a correlation between the light emission amounts of the R, G, and B light emitters of the light source Ln and the chromaticity and luminance of the light source Ln. The light emission amount of the R light emitter of the light source Ln is R _Ln , the light emission amount of the G light emitter of the light source Ln is G _Ln , the light emission amount of the B light emitter of the light source Ln is B _Ln, and the tristimulus value of the light emission amount R _Ln is ( _{X RLn, Y RLn, Z RLn} ), the tristimulus values of the light emission quantity _{G Ln (X GLn, Y GLn} , Z GLn), the tristimulus values of the light emission quantity _{B Ln (X BLn, Y BLn} , Z BLn) and Then, the tristimulus values (X _Ln , Y _Ln , Z _Ln ) of the light source Ln are expressed as the following equation (1).
[Expression 1]

[0029]
In the above equation (1), C _n is the light emission amount (R _Ln , G _Ln , B _Ln ) of the R, G, and B light emitters of the light source Ln and the tristimulus values (X _Ln , Y _Ln , Z) of the light source Ln. _Ln ) is a 3 × 3 matrix showing the correlation. This correlation matrix C _n is a matrix unique to each light source, and can be obtained in advance by actual measurement or the like.
[0030]
In addition, the light in the partial area Am of the display unit 11 is a mixed light of the light that has reached the area Am with a specific attenuation factor from each of the four light sources L1 to L4. The tristimulus values (X _An , Y _An , Z _An ) of light in such an area Am are expressed as the following equation (2).
[Expression 2]

[0031]
In the above equation (2), k _mn is a coefficient representing the attenuation rate until the light from the light source Ln reaches the area Am. In the above equation (2), the attenuation factors of the X, Y, and Z light from the light source Ln are all the same value _kmn . However, when the attenuation factors of the X, Y, and Z light are different, the attenuation is performed. The rate coefficient _kmn is a value unique to each of the X, Y, and Z lights.
[0032]
The n-th term in the above expression (2) represents the contribution ratio of the light emission amount of the light source Ln in the area Am. When all of the light sources L1 to L4 are caused to emit light, the tristimulus values (X _Am , Y _Am , Z _Am ) of light in the area Am are obtained by adding all the first to fourth terms of the formula (2). It will be a thing. For example, when only the light source L1 is caused to emit light, the tristimulus values (X _Am , Y _Am , Z _Am ) of light in the area Am are the first term of the above equation (2).
[0033]
The color sensor Sm detects light in the area Am. There is a correlation between the tristimulus values of light in the area Am and the R, G, B detected light amounts of the color sensor Sm. If the tristimulus values of light in the area Am are (X _Am , Y _Am , Z _Am ), when the spectral sensitivity characteristics of the color sensor Sm satisfy the router condition, the R, G, B detected light amounts (R _Sm , G _Sm , B _Sm ) are expressed as the following equation (3).
[Equation 3]

[0034]
In the above equation (3), D _m is the tristimulus value (X _Am , Y _Am , Z _Am ) of light in the area Am and the detected light amount (R _Sm , G _Sm , B _Sm ) of the color sensor Sm. 3 × 3 matrix representing correlation. The correlation matrix _Dm is a matrix unique to each area (each color sensor), for example, and can be obtained in advance by actual measurement or the like.
[0035]
By combining the above formulas (1) to (3), the light emission amounts (R _L1 , G _L1 , B _L1 ) to (R _L4 , G) of the R, G, B color light emitters of the four light sources L1 to L4 are combined. _L4 , B _L4 ) and the following equation (4) representing the correlation between the light amount detected by the color sensor Sm (R _Sm , G _Sm , B _Sm ) can be derived.
[Expression 4]

[0036]
In the above equation (4), E _mn represents the light emission amounts (R _Ln , G _Ln , B _Ln ) of the R, G, and B light emitters of the light source Ln and the detected light amounts (R _Sm , G _Sm , B) of the color sensor Sm. _Sm ) is a 3 × 3 matrix and E _mn = D _m × k _mn × C _n .
[0037]
The n-th term in the above expression (4) represents the contribution rate of the light emission amount of the light source Ln in the detected light amount (R _Sm , G _Sm , B _Sm ) of the color sensor Sm. When all of the light sources L1 to L4 are caused to emit light, the detected light amount (R _Sm , G _Sm , B _Sm ) of the color sensor Sm is obtained by adding all the first to fourth terms of the above formula (4). . For example, when only the light source L1 is caused to emit light, the detected light amount (R _Sm , G _Sm , B _Sm ) of the color sensor Sm is the first term of the above equation (4).
[0038]
Correlation matrices E _{1m to} E _4m indicate the amount of light emitted from only one of the R, G, and B light emitters of light source Lm among light sources L1 to L4 and the color sensor S1. ˜S4 detected light amounts (R _S1 , G _S1 , B _S1 ) to (R _S4 , G _S4 , B _S4 ) can be obtained in advance.
[0039]
For example, when only the R light emitter of the light source L1 emits light, the light emission amount R _L1 of the light emitter and the detected light amounts (R _S1 , G _S1 , B _S1 ) to (R _S4 , G _S4 , B) of the color sensors S1 to _S4 . _S4) with, it is possible to obtain the three values of the first column of the correlation matrix _E 11 _{to E 41,} the light emission amount _{G L1} and color sensor S1~ the emitters when light is emitted only G light emitter of the light source L1 With the detected light amounts (R _S1 , G _S1 , B _S1 ) to (R _S4 , G _S4 , B _S4 ) of _S4 , three values in the second column of the correlation matrices E _{11 to} E ₄₁ can be obtained, and the light source L1 The light emission amount B _L1 of the light emitter when emitting only the B light emitter and the detected light amounts (R _S1 , G _S1 , B _S1 ) to (R _S4 , G _S4 , B _S4 ) of the color sensors, Correlation matrix E Three values in the third column of _{11 to} E ₄₁ can be obtained.
[0040]
By substituting previously obtained correlation matrices E _{11 to} E ₄₄ into the above equation (4), R, G of the light sources L _{1 to} L ₄ for each of the total 12 detected light amounts R _{S1 to} B _S4 of the color sensors _{S 1 to S 4.} , Correlation equations with the light emission amounts R _{L1 to} B _{L4 of} the B light emitters are obtained.
[0041]
By substituting a total of twelve detected light amounts R _{S1 to} B _S4 of the color sensors S1 to S4 into the total of twelve correlation equations obtained in advance, a total of twelve R, G, and B light emitters of the light sources L1 to L4 are obtained. Simultaneous equations consisting of 12 equations with the light emission amounts R _{L1 to} B _L4 as variables are obtained, and the light emission amounts (detected light emission amounts) of the R, G and B light emitters of the light sources L1 to L4 are obtained by solving these simultaneous equations. Each of R _{L1 to} B _L4 can be calculated.
[0042]
Thus, by using a total of 12 correlation equations obtained from the above equation (4), from the detected light amounts R _{S1 to} B _S4 of the color sensors S1 to _S4 , the R, G, and B light emitters of the light sources L1 to L4 The light emission amount (detected light emission amount) R _{L1 to} B _L4 can be calculated.
[0043]
FIG. 3 is a flowchart showing a light source calibration procedure in the image display apparatus according to the embodiment of the present invention. The light source calibration procedure of the present embodiment will be described below with reference to FIG.
[0044]
In the correlation data memory 24, the values of the correlation matrices E _{11 to} E ₄₄ of the above equation (4) are stored in advance. The values of these correlation matrices E _{11 to} E ₄₄ are set using actual measured values and the like in the design stage and the production stage. In addition, the total of twelve correlation equations obtained from the equation (4) are also stored in the correlation data memory 24 as part of the calculation algorithm for the detected light emission amounts R _{L1 to} B _L4 .
[0045]
Accordingly, in the correlation data memory 24, there are a total of twelve correlation equations obtained from the equation (4), in which the values of the correlation matrices E _{11 to} E _{44 in} the equation (4) are known. Are stored in advance as correlation data. Note that the above calculation algorithm may be stored in the light source emission amount calculation unit 23.
[0046]
The light source reference light emission amount data memory 25 stores light source reference light emission amount data composed of reference light emission amounts of the respective light emitters of the respective light sources in advance. This light source reference light emission amount data is the light emission amount data of each light emitter of each light source when a screen having no color unevenness or brightness unevenness is obtained in the entire area, and is designed and produced (the light source emission in the production stage). This is set at the time of initial setting of the quantity).
[0047]
Further, the light source reference emission amount data memory 25 stores in advance an allowable range of detected emission amount data with respect to the reference emission amount data. This allowable range is set in a design stage, a production stage, or the like according to the display quality or purpose of use of the image display device, for example.
[0048]
3, at the start of light source calibration, if the light sources L1 to L4 are emitting light, the process immediately proceeds to step 1. If the light sources L1 to L4 are not emitting light, the light source control amount calculation unit 26 of the light source control unit 20 performs. The light source driving unit 21 is controlled, the light sources L1 to L4 are caused to emit light by the light source driving unit 21, and the process proceeds to step 1 after waiting until the light source is stabilized as necessary. The light source calibration can be started at an arbitrary timing by the user, and can be automatically set to be performed at a predetermined time interval or a predetermined time.
[0049]
In Step 1, the R, G, B light amounts in the area A1 are obtained by the color sensor S1, the R, G, B light amounts in the area A2 are obtained by the color sensor S2, and the R, G, B light amounts in the area A3 are obtained by the color sensor S3. Are detected respectively.
[0050]
Then, the R, G, B detected light amounts (R _S1 , G _S1 , B _S1 ) of the color sensor S1, the R, G, B detected light amounts (R _S2 , G _S2 , B _S2 ) of the color sensor _S2 , and the color sensor S3. R, G, B detected light amounts (R _S3 , G _S3 , B _S3 ) and R, G, B detected light amounts (R _S4 , G _S4 , B _S4 ) of the color sensor S 4 are sent to the A / D converter 22. The A / D converter 22 converts the digital value.
[0051]
In the next step 2, the detected light amount data converted into a digital value by the A / D conversion unit 22 is sent to the light source emission amount calculation unit 23 of the light source control unit 20, and the light source emission amount calculation unit 23 uses the correlation data memory 24. The total 12 detected light quantities R _{S1 to} B _S4 are used to calculate the detected light emission amounts (R _L1 , G _L1 , B _L1 ) of the R, G, and B light emitters of the light source L1 from the total 12 detected light amounts R _{S1 to} B _S4. ), Detected light emission amounts of the R, G, and B light emitters of the light source L2 (R _L2 , G _L2 , B _L2 ), detected light amounts of the R, G, and B light emitters of the light source L3 (R _L3 , G _L3 , and B _L3). ), And the detected light emission amounts (R _L4 , G _L4 , B _L4 ) of the R, G, and B light emitters of the light source L4.
[0052]
In the next step 3, the detected light emission amount data calculated by the light source light emission amount calculation unit 23 is sent to the light source control amount calculation unit 26, and the light source control amount calculation unit 26 detects each light emitter of each light source. A difference between the light emission amount and the reference light emission amount stored in the memory 25 is obtained, and the difference is compared with an allowable range stored in the memory 25. And when the said difference of any light-emitting body exceeds the said tolerance | permissible_range, it progresses to step 4.
[0053]
In step 4, when the detected light emission amount exceeding the allowable range is smaller than the reference light emission amount, the control amount of the light emitter is changed in a direction to increase the light emission amount of the light emitter, and the detected light emission exceeding the allowable range is detected. When the amount is larger than the reference light emission amount, the control amount of the light emitter is changed so as to reduce the light emission amount of the light emitter, and the light source control data is sent to the light source drive unit 21.
[0054]
Then, after the light source driving unit 21 re-adjusts the light emission amount of each light emitter of each light source according to the light source control data in which the control amount is changed, the above steps 1 to 3 are performed again.
[0055]
In this way, the respective light emission amounts of the respective light sources are adjusted, and if the difference between the detected light emission amount and the reference light emission amount is within the allowable range for all the light emitters of all the light sources in step 3 above, This light source calibration procedure is terminated.
[0056]
As described above, according to the embodiment of the present invention, the detected light emission of each light source from the detected light amount using the correlation equation between the detected light amounts of the plurality of color sensors and the light emission amounts of the plurality of light sources. By calculating the amount of light and adjusting the light emission amount of each light source based on these detected light emission amounts, the image quality can be improved in a non-self-luminous configuration in which images are displayed on the screen by light from a plurality of light sources. It is possible to easily calibrate the chromaticity and brightness of the screen and the color unevenness and brightness unevenness in the screen without deteriorating.
[0057]
Furthermore, since the conventional image display apparatus has one color sensor, it is necessary to install the color sensor in the center of the screen, and the color sensor must be installed at a position that hinders image display. However, in the image display device according to this embodiment, the light amounts of different areas on the screen are detected by a plurality of color sensors, respectively. Since it can be provided around the screen and the color sensor can be installed at a position that does not interfere with image display, light source calibration can be performed as needed.
[0058]
In the above embodiment, four color sensors are provided in an image display device having four light sources. However, if the number of color sensors is equal to or greater than the number of light sources, the above formula (4) is used to determine the light source. Since the detected light emission amount of the illuminant can be calculated, the number of color sensors can be the same as or more than the number of light sources.
[0059]
In the above embodiment, it is assumed that the gradation characteristic is linear. However, if the gradation characteristic is not linear due to the characteristics of the light source or the color sensor, the gradation characteristic is obtained in advance by measurement or the like. In addition, the amount of light emitted from the light source can be calculated in the same manner by incorporating it into the correlation equation (4).
[0060]
【The invention's effect】
As described above, according to the present invention, the chromaticity and brightness of the screen and the color in the screen without degrading the image quality in the non-self-luminous configuration in which the image is displayed on the screen by light from a plurality of light sources. There is an effect that unevenness and unevenness in brightness can be easily calibrated.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a display panel in an image display device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration for light source calibration and a light source calibration procedure in the image display apparatus according to the embodiment of the present invention.
FIG. 3 is a flowchart showing a light source calibration procedure in the image display apparatus according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Display part, 12 Light-guide plate, L1, L2, L3, L4 Light source, S1, S2, S3, S4 Color sensor, 20 Light source control part, 21 Light source drive part, 22 A / D conversion part, 23 Light source light emission amount calculating part 24 correlation data memory, 25 light source reference light emission amount data memory, 26 light source control amount calculation unit.

Claims (10)

In an image display device that displays an image on a screen by light from a plurality of light sources each capable of adjusting light emission chromaticity and light emission luminance,
A plurality of color sensors that respectively detect chromaticity and brightness for different areas of the screen;
Correlation storage means for storing a correlation equation between the detected chromaticity and detected luminance of each of the color sensors and the emitted chromaticity and emitted luminance of each of the light sources;
An arithmetic means for calculating the detected light emission chromaticity and the detected light emission luminance of each light source from the detected chromaticity and the detected luminance using the correlation equation;
An image display device comprising: adjusting means for adjusting the light emission chromaticity and light emission luminance of each of the light sources based on the detected light emission chromaticity and the detection light emission luminance. Each of the light sources described above is adjusted for light emission chromaticity and light emission brightness by individually adjusting the light emission amounts of the light emitters of a plurality of colors.
Each of the color sensors detects the light amounts of a plurality of colors and outputs the detected light amounts as data of a plurality of channels.
The correlation equation is a correlation equation between the respective detected light amounts of the respective color sensors and the light emission amounts of the respective light emitters of the respective light sources,
The calculation means calculates the detected light emission amount of the respective light emitters of the respective light sources from the detected light amount,
The image display apparatus according to claim 1, wherein the adjusting unit adjusts the light emission amount of each of the light emitters of each of the light sources. The light emitters of the plurality of colors are R, G, and B3 light emitters,
The image display apparatus according to claim 2, wherein the plurality of channels are three channels of R, G, and B. Reference data storage means for storing light source reference emission data to be the reference emission chromaticity and reference emission luminance of each of the light sources is further provided,
The image display device according to claim 1, wherein the adjustment unit adjusts the light emission chromaticity and light emission luminance of each light source so as to coincide with the light source reference light emission data of the light source.   2. The image display device according to claim 1, wherein the number of the color sensors is equal to or greater than the number of the light sources. In an image display method for displaying an image on a screen by light from a plurality of light sources each capable of adjusting light emission chromaticity and light emission luminance,
A first step of detecting chromaticity and brightness by a plurality of color sensors for different areas of the screen;
Using the correlation equation between the detected chromaticity and detected luminance of each of the color sensors and the emitted chromaticity and emitted luminance of each of the light sources, the detected emitted chromaticity of each of the light sources and the detected chromaticity and A second step of calculating the detected emission luminance;
And a third step of adjusting the light emission chromaticity and light emission luminance of each of the light sources based on the detected light emission chromaticity and the detection light emission luminance. Each of the light sources described above is adjusted for light emission chromaticity and light emission brightness by individually adjusting the light emission amounts of the light emitters of a plurality of colors.
In the first step, each of the color sensors detects light amounts of a plurality of colors, and outputs the detected light amounts as data of a plurality of channels.
The second step uses the correlation equation between the respective detected light amounts of the respective color sensors and the emitted light amounts of the respective light emitters of the respective light sources to calculate the above-mentioned values of the respective light sources from the detected light amounts. Calculate the detected luminescence of each illuminant,
The image display method according to claim 6, wherein the third step adjusts a light emission amount of each of the light emitters of each of the light sources. The light emitters of the plurality of colors are R, G, and B3 light emitters,
The image display method according to claim 7, wherein the plurality of channels are three channels of R, G, and B. In the correlation storage means, as the correlation equation, the correlation between the light emission amount of each of the light emitters of each of the light sources and the tristimulus value of the emitted light, and the tristimulus value of light in each of the areas, 3. The image display device according to claim 2, wherein a correlation formula determined based on a correlation between the detected light amounts of the color sensors is stored. In the second step, as the correlation equation, the correlation between the light emission amount of each of the light emitters of each of the light sources and the tristimulus value of the emitted light, and the tristimulus value of light in each of the areas, 8. The image display method according to claim 7, wherein a correlation equation determined based on a correlation between the detected light amounts of the color sensors is used.

Images